[Docs] (MG_Remote): record R-15 and split the emit table's 71 slots into answered-locally, emitted and Fatal, with the forty-one null checks that are really capability probes

.github/workflows/test.yml

@@ -601,7 +601,26 @@ jobs:
       # only in the pull `integration` job, where a MOBILEGL_PIPE_PUSH value steers nothing
       # (Config.h declares the field inside the push guard) and both arms are the same legacy path.
       # A lane that cannot go red where it is installed is not a gate (ROADMAP.md:7).
-      - name: The handle-ABA, CSO and P3a subsystem controls (G8, G10, G12)
+      # P4a ADDS THREE ALTERNATIVES, and each one is here because this is the only CI job that
+      # unpacks a push build:
+      #   * `ObjectSubsystem` reaches the three DirectGLES.ObjectSubsystemControl. entries - the
+      #     0x1fff-vs-0x1ff A/B and the 0x9ff dependency refusal (G12). `ResourceSubsystem` does
+      #     NOT match it: the two families are named apart on purpose, because they are different
+      #     phases' switches and a filter that merged them would hide one behind the other.
+      #   * `TextureParamsWithoutASamplerView` reaches G9's four cases, the scenario ROADMAP.md:20
+      #     names by hand. It runs in the ambient lanes, which the label already selects - but this
+      #     step is where those cases run against a PUSH library, and G9's whole claim is about the
+      #     push path. All four cases are green on the contract commit - including the one D-E3
+      #     expected to be red, for the reason the scenario's header records - so this row is green
+      #     from the day it lands and goes red only if a reachability path stops syncing texture
+      #     parameters at all, which is the coupling ARCHITECTURE.md:100 exists to remove.
+      #   * `TextureUploadShape` is RECORDED, not gated (D-D4): it asserts that the two upload-shape
+      #     counters could be read and that they agree, and prints the shape for MEASUREMENTS.md. It
+      #     is in the filter so that the number is actually collected on every run - an unmeasured
+      #     shape is not a recorded one - and because its own assertions can go red.
+      # As with the four before them, each alternative is the SHORTEST string that selects only what
+      # it means to.
+      - name: The handle-ABA, CSO, subsystem and texture-parameter controls (G8, G8b, G9, G10, G12)
         working-directory: build-verify
         env:
           MOBILEGL_ITEST_REQUIRE_GPU: "1"
@@ -612,7 +631,7 @@ jobs:
           ulimit -c unlimited
           sudo sysctl -w kernel.core_pattern='/tmp/core.%e.%p'
           ctest --output-on-failure -L integration-gpu \
-            -R 'HandleRecycle|CsoContentAddressing|ResourceSubsystem|MapPersistentRoundtrip' \
+            -R 'HandleRecycle|CsoContentAddressing|ResourceSubsystem|MapPersistentRoundtrip|ObjectSubsystem|TextureParamsWithoutASamplerView|TextureUploadShape' \
             --no-tests=error -j 4
 
       # The arming lanes' logs, and ONLY those. Each lane shares one MOBILEGL_LOG_FILE_PATH and the
@@ -771,7 +790,16 @@ jobs:
         run: sudo apt-get update && sudo apt-get install -y clang-20 libx11-dev
 
       - name: Include-closure assertions and negative control
-        run: python3 scripts/check_include_closure.py --mode both --compiler clang++-20 --self-test --require-all
+        # --expect-probes 4 (contract-v2.md 7.6): an exit code cannot tell four probes from none,
+        # so a --probe typo or a manifest edit that selected nothing would run zero probes and
+        # exit 0 - the second half of the finding that added the flag. The count is the length of
+        # scripts/check_include_closure.py's PROBES list and changing one means changing the other.
+        #
+        # --compiler stays clang++-20, which is what the step above installs (Debian's clang-20
+        # package ships /usr/bin/clang++-20). It is deliberately NOT the bare `clang++` the local
+        # campaign gate spells: that spelling exists because the WSL box has no clang++-20, and
+        # copying it here would trade a version-pinned compiler for whatever the runner has.
+        run: python3 scripts/check_include_closure.py --mode both --compiler clang++-20 --self-test --require-all --expect-probes 4
 
   benchmark:
     runs-on: ubuntu-latest
@@ -1557,12 +1585,18 @@ jobs:
     # Deliberately independent of build-linux: these are source-level gates, they take
     # seconds, and a broken build must not hide a drifted interface.
     env:
-      # P3a's base ref, for the G5 region gate below. It is 44c2b5cf and NOT the workflow's
-      # baseline_sha input: that input is the SYMBOL baseline (087685d1, P1's G1 reading) and it
-      # is empty on a push, whereas this gate asks "did the buffer pool, the deferred-release
-      # drain and the three rings move since the phase started". INTEGRATOR-DECISIONS ID-1 is
-      # where the ref comes from.
-      BASELINE: "44c2b5cf"
+      # THE CURRENT PHASE's base ref, for the two G5 region gates below. It is 37da3c3a - P4a's
+      # base ref, INTEGRATOR-DECISIONS ID-1 - and NOT the workflow's baseline_sha input: that input
+      # is the SYMBOL baseline (087685d1, P1's G1 reading) and it is empty on a push, whereas these
+      # gates ask "did the do-not-touch list move since the phase started".
+      #
+      # IT MOVED FROM P3a's 44c2b5cf TO P4a's 37da3c3a WITH THE PHASE, and that is a deliberate
+      # narrowing rather than a loss: P3a's eleven functions were compared against 44c2b5cf at P3a's
+      # own exit and were byte-identical there, so 37da3c3a carries the same bodies (measured: the
+      # eleven shas at 37da3c3a are the eleven shas at 44c2b5cf, and FlushPendingRangesFrom's is
+      # still the sha pinned in the script at 3e298c9a). What the two gates now both answer is "did
+      # anything on the list move during P4a", which is the question this phase can act on.
+      BASELINE: "37da3c3a"
 
     steps:
       - name: Checkout repo
@@ -1664,6 +1698,39 @@ jobs:
         if: ${{ github.ref == 'refs/heads/feat/disaggregated' || github.event_name == 'workflow_dispatch' }}
         run: bash scripts/p3a_untouched_regions.sh --self-test
 
+      # A GATE AS OF P4a (G5), and a SECOND script rather than an edit to the one above. P4a extends
+      # the same claim to the rest of ARCHITECTURE.md:318's do-not-touch list - the unpack PBO ring's
+      # staging repack and its two helpers, the attachment permutation, the D24S8 sampling-emulation
+      # core and the format-caveat handler - which is SEVENTEEN regions across THREE files
+      # (BRIEF-P4A.md D-N: P3a's eleven, which P4a must not touch either, plus P4a's six). The
+      # parent's SOURCE_PATH is a single file, so the extension needed a per-region source path and
+      # a region KIND (DepthStencilSamplingReadImpl is a namespace, not a function); everything else
+      # about the extraction is its parent's, verbatim.
+      #
+      # Both scripts run. The parent keeps answering its own question against its own eleven, so a
+      # regression in either half names itself, and neither gate can be silenced by editing the
+      # other's list.
+      #
+      # Same feat/disaggregated-or-dispatch guard as the P3a step, for the same reason: the question
+      # is "did these move since the phase started", and on dev - where unrelated buffer and texture
+      # fixes land on their own schedule - it would be a question nobody posed. It belongs with the
+      # TEMPORARY trigger lines at the top of this file and retires with them.
+      #
+      # --self-test is the half that keeps it honest and is not optional: a comparison that silently
+      # stopped comparing produces exactly the same green as seventeen untouched regions. It runs
+      # three positive controls (seventeen regions extracted, an untouched copy compared equal, an
+      # edit OUTSIDE them invisible in all three files) and FOUR negative ones - ClearBufferPool,
+      # FlushPendingRangesNow, RecomputeBackendColorSlots and StageBlocksIntoUnpackRing, each
+      # perturbed on its own and each required to be named BY NAME - and fails if any of them does
+      # not answer.
+      - name: The unpack ring, the attachment permutation, the D24S8 core and the format caveat did not move (G5)
+        if: ${{ github.ref == 'refs/heads/feat/disaggregated' || github.event_name == 'workflow_dispatch' }}
+        run: bash scripts/p4a_untouched_regions.sh "${BASELINE}" HEAD
+
+      - name: The P4a untouched-region gate can still fail (G5)
+        if: ${{ github.ref == 'refs/heads/feat/disaggregated' || github.event_name == 'workflow_dispatch' }}
+        run: bash scripts/p4a_untouched_regions.sh --self-test
+
       # Warning only for now: the disaggregation documents are still being written, and a
       # lint that fails a rewrite in progress teaches people to ignore it. It becomes
       # --strict when the documents settle.

CMakeLists.txt

@@ -21,6 +21,13 @@ option(MOBILEGL_IOS               "Build MobileGL for iOS instead of macOS when
 # That emptiness is one of the two byte-level equalities the plan's validation
 # gates keep (section 10.3).
 option(MOBILEGL_BUILD_DISAGGREGATED "Build the MG_Remote transport layer (two-process shape)" OFF)
+# The CI / debugging shape (ARCHITECTURE.md:581): both roles in ONE process, talking over the
+# same SEG_CMD ring and the same G3 codec a spawned server would use. It IMPLIES
+# MOBILEGL_BUILD_DISAGGREGATED (below) and additionally admits the role-isolation shims that
+# only make sense when the two roles share an address space. It is a SUPERSET, never a
+# substitute: MOBILEGL_TRANSPORT=inproc is what selects the shape at run time, and this option
+# only decides whether the shims are compiled in.
+option(MOBILEGL_BUILD_DISAGGREGATED_INPROC "Compile the in-process (one-process, two-role) split shims; implies MOBILEGL_BUILD_DISAGGREGATED" OFF)
 option(MOBILEGL_BUILD_SERVER_SPIKE "Build the P0 spike-A MobileGLServer delivery-chain executable (Android only)" OFF)
 # The PipeInputs strangler (ARCHITECTURE.md 9.2). OFF is the pull build and must stay
 # byte-identical to a tree without either option: MGB_CTX is the live GLContext, no
@@ -445,6 +452,17 @@ set(SOURCE_FILES
 # option OFF not one file here is compiled and no include path is added.
 # ---------------------------------------------------------------------------
 
+# MOBILEGL_BUILD_DISAGGREGATED_INPROC implies MOBILEGL_BUILD_DISAGGREGATED. A normal
+# variable, not a forced cache write, for the reason the two implications below give: an
+# operator's cache entry stays theirs and only this configure is shadowed. Ordered BEFORE the
+# flatbuffers guard so that a missing submodule turns BOTH off together - an INPROC build
+# with the transport shadowed off would compile a role-isolation shim over no roles.
+if (MOBILEGL_BUILD_DISAGGREGATED_INPROC AND NOT MOBILEGL_BUILD_DISAGGREGATED)
+    message(STATUS "MobileGL: MOBILEGL_BUILD_DISAGGREGATED_INPROC=ON forces "
+                   "MOBILEGL_BUILD_DISAGGREGATED ON for this configure")
+    set(MOBILEGL_BUILD_DISAGGREGATED ON)
+endif()
+
 # FlatBuffers is a submodule and its runtime is header-only. Guard both ways:
 # a checkout without the submodule must configure and build, just without the
 # disaggregated shape, rather than fail with a missing-header error a hundred
@@ -462,6 +480,24 @@ if (MOBILEGL_BUILD_DISAGGREGATED AND
     # all. Shadowing the cache entry for this configure only keeps the operator's ON where it
     # was, so the next configure - with the submodule there - honours it.
     set(MOBILEGL_BUILD_DISAGGREGATED OFF)
+    # And with it the shim option, or the `-DMOBILEGL_BUILD_DISAGGREGATED_INPROC=1` below
+    # would still be defined over a build with no MG_Remote in it at all.
+    set(MOBILEGL_BUILD_DISAGGREGATED_INPROC OFF)
+endif()
+
+# MOBILEGL_BUILD_DISAGGREGATED implies MOBILEGL_PIPE_PUSH (P5 c0). The split path IS the
+# pushed path: MG_Remote's server decodes records into the MGPipeApply* entry points, which
+# live in MG_Pipe/PipeApply.cpp, which the PIPE_PUSH block below is what compiles. Without
+# this, `-DMOBILEGL_BUILD_DISAGGREGATED=ON` alone configures and then fails to link the
+# applier - and the shape it fails in (MG_Remote compiled, no applier) is indistinguishable
+# at the CMake level from a legitimate transport-only build, which is why it is stated here
+# rather than left to whoever hits the link error. Same normal-variable form as the two
+# implications above.
+if (MOBILEGL_BUILD_DISAGGREGATED AND NOT MOBILEGL_PIPE_PUSH)
+    message(STATUS "MobileGL: MOBILEGL_BUILD_DISAGGREGATED=ON forces MOBILEGL_PIPE_PUSH ON for "
+                   "this configure: the split path decodes into the MGPipe applier, and the "
+                   "applier is what MOBILEGL_PIPE_PUSH compiles")
+    set(MOBILEGL_PIPE_PUSH ON)
 endif()
 
 # MOBILEGL_PIPE_VERIFY implies MOBILEGL_PIPE_PUSH: the comparator compares the pushed block
@@ -491,6 +527,12 @@ if (MOBILEGL_PIPE_PUSH)
         MobileGL/MG_Pipe/MGPipeRenderStateSpans.cpp
         MobileGL/MG_Pipe/PipeApply.cpp
         MobileGL/MG_Impl/Pipe/SlotAllocator.cpp
+        # P4a's contract: the reflection-archive serializer over ProgramArtifacts.h's
+        # VisitFields tables. Push-only for the same G1 reason as the three above - in
+        # monolith the archive never crosses (create_shader_state hands the two structs over
+        # by pointer beside the record), so the codec is live code only in the VERIFY lane,
+        # where the applier serialises, deserialises and field-compares before storing.
+        MobileGL/MG_State/GLState/ProgramState/ProgramArtifactsCodec.cpp
     )
 endif()
 
@@ -510,6 +552,28 @@ if (MOBILEGL_BUILD_DISAGGREGATED)
         # Keeps MG_Util/Debug/Log.h - and through it the GL frontend's
         # umbrella header - out of the header-only wire code (WireLog.h).
         MobileGL/MG_Remote/Transport/WireLog.cpp
+        # ---- P5: the three new directories ------------------------------
+        # Wire/   the G3 codec: MGPWireRec_* in and out of SEG_CMD, blobs and
+        #         var-tails in and out of SEG_STAGE.                    [w1]
+        # Client/ the emitting role: session, the 69-slot emit table, the
+        #         caps mirror.                                          [c1]
+        # Server/ the applying role: session, the applier bridge onto the
+        #         existing MGPipeApply* free functions, the apply thread. [v1]
+        #
+        # Every file below lands in P5 as a HEADER plus a .cpp of named
+        # Fatal stubs, so that all seven P5 packages compile and link on day
+        # one against signatures that cannot then move under them. A stub is
+        # MGLOG_F + std::abort, never a silent no-op: an unimplemented
+        # emitter that returns quietly is how a split lane runs monolith and
+        # goes green (ARCHITECTURE.md 10.3).
+        MobileGL/MG_Remote/CapsCodec.cpp
+        MobileGL/MG_Remote/Wire/PipeWireCodec.cpp
+        MobileGL/MG_Remote/Client/ClientSession.cpp
+        MobileGL/MG_Remote/Client/EmitTables.cpp
+        MobileGL/MG_Remote/Client/CapsMirror.cpp
+        MobileGL/MG_Remote/Server/ServerSession.cpp
+        MobileGL/MG_Remote/Server/PipeApplier.cpp
+        MobileGL/MG_Remote/Server/ServerLoop.cpp
     )
 endif()
 

MobileGL/Config.h

@@ -322,16 +322,28 @@ namespace MobileGL::MG_Config {
         // 0 - the only shipped value until the migration lands - is "pull everything",
         // i.e. exactly today's behaviour, and is the default of a PULL build, where the
         // knob is meaningless anyway. A PUSH build defaults to every subsystem migrated so
-        // far (MG_Pipe::kMGPipeSubsystemsMigratedAtP3a), so MOBILEGL_PIPE_PUSH=0 in the
-        // environment is the all-pull control and 0x7f (kMGPipeSubsystemsMigratedAtP2) is
-        // the "P2 only" control P3a's A/B is run against. Accepts decimal or 0x-prefixed
-        // hex, and operators pass it as hex, so the bits are listed here (MG_Pipe/MGPipe.h
-        // owns them):
+        // far (MG_Pipe::kMGPipeSubsystemsMigratedAtP4a), so MOBILEGL_PIPE_PUSH=0 in the
+        // environment is the all-pull control and 0x1ff (kMGPipeSubsystemsMigratedAtP3a) is
+        // the "everything before P4a" control P4a's A/B is run against - each phase's
+        // constant survives as the next phase's control, which is why none of them is ever
+        // edited. Accepts decimal or 0x-prefixed hex, and operators pass it as hex, so the
+        // bits are listed here (MG_Pipe/MGPipe.h owns them):
         //   0x01 render state (create/bind_render_state + set_dynamic_state)
         //   0x02 pixel pack        0x04 patch state      0x08 vertex attrib defaults
         //   0x10 residual values   0x20 Espryt slots     0x40 Magma vertex input
         //   0x80 resources (the resource_* family: the seven BufferBackendOps hooks)
         //   0x100 vertex input (vertex elements / vertex buffers / index buffer)
+        //   0x200 framebuffer (set_framebuffer_state)              - requires 0x400
+        //   0x400 texture resources (texture + renderbuffer resource_*,
+        //         set_texture_params)                              - requires 0x80 AND 0x800
+        //         (the built-in sampler CSO a set_texture_params record names is minted by
+        //         the sampler family alone, ID-15; the four rows are MG_Impl/Pipe/PipeFill.cpp's
+        //         kMGPipeP4aFamilyDependencies, mirrored bit for bit by Espryt's resolvers)
+        //   0x800 samplers (sampler CSO, sampler view, set_sampler_views /
+        //         bind_sampler_states / set_shader_images)         - requires 0x400
+        //   0x1000 programs (shader CSO, set_draw/dispatch_program, global constants)
+        //   A dependency that is not met is REFUSED with one ERROR naming both bits and the
+        //   family runs its legacy arm; it is never half-run.
         //   1<<63 NOT a subsystem, a BEHAVIOUR: turn OFF client-side content addressing of
         //         CSOs, so every pipeline-version change mints a fresh CSO and the map is
         //         never probed. The negative control the CSO design is measured against.
@@ -402,4 +414,103 @@ namespace MobileGL::MG_Config {
         String PipeStatsFile;
     };
     extern FeaturesTable Features;
+
+    // ---------------------------------------------------------------------------------
+    // P5: the transport selector and the MOBILEGL_IPC_* family (ARCHITECTURE.md 16, 附 A)
+    // ---------------------------------------------------------------------------------
+    //
+    // MOBILEGL_TRANSPORT = monolith | inproc | spawn | unix:<path> | pipe:<name>.
+    //
+    // WHY `Transport` IS NOT A FeaturesTable MEMBER. ARCHITECTURE.md:580 requires that with
+    // MOBILEGL_BUILD_DISAGGREGATED=OFF it be a `constexpr Monolith`, so that the single hook
+    // in MG_Backend/Init.cpp compiles away entirely rather than becoming a branch nobody can
+    // take. A FeaturesTable member is a runtime field in every build, which is the opposite
+    // of that; it would also resize MG_Config::Features and break G1 (the pull build's
+    // symbol set must not move) for the same reason the MOBILEGL_PIPE_VERIFY knobs above sit
+    // behind their own #if.
+    //
+    // ONE CONSEQUENCE, STATED SO IT IS NOT REDISCOVERED: in a build without the option,
+    // MOBILEGL_TRANSPORT=inproc is ACCEPTED BY THE ENVIRONMENT AND SILENTLY IGNORED - the
+    // parser below does not exist to complain about it, and putting a complaint in the
+    // unconditional part of ConfigLoader would move a pull-build symbol. That is the exact
+    // shape of "the split lane ran monolith and went green", so the gate against it is a
+    // BUILD-level check, not a runtime one: `nm --defined-only libMobileGL.so | grep -i
+    // MG_Remote` must be non-empty in build-split (CONTRACT-P5.md table 3, and the CI job
+    // P5 adds beside build-linux-verify).
+    enum class TransportMode : Uint8 {
+        Monolith = 0,  // today's in-library backend; no MG_Remote object is constructed
+        InProcess = 1, // P5: a real apply thread in this process, over the same G3 codec
+        Spawn = 2,     // P6: fork/exec MobileGLServer, socketpair
+        UnixSocket = 3,// P6: connect to an existing AF_UNIX endpoint (Endpoint = <path>)
+        NamedPipe = 4, // P6: Windows named pipe (Endpoint = <name>)
+    };
+
+#if MOBILEGL_BUILD_DISAGGREGATED
+    // Parsed once by MG_ConfigLoader::Init(). Defaults to Monolith even here: building the
+    // transport in is not the same as using it, and every existing lane of a build-split
+    // must keep running monolith unless it is asked for one.
+    extern TransportMode Transport;
+    // The <path> of `unix:` / the <name> of `pipe:`. Empty for the other three modes.
+    extern String TransportEndpoint;
+
+    // The MOBILEGL_IPC_* family. A separate table rather than more FeaturesTable members,
+    // for the G1 reason above and because every field here is meaningless without the
+    // transport: a build that cannot reach the MG_Remote code cannot honour one of them.
+    //
+    // P5 lands exactly the knobs P5's own packages read. A later phase's knob is added HERE,
+    // through the integrator, and not invented at its call site - ARCHITECTURE.md:615 holds
+    // the full planned inventory (PRESENT_CREDIT, POLL_ESCALATE, SHADOW_SHM,
+    // INLINE_PAYLOADS, TRACE, ATTACH, RESPAWN, IDLE_EXIT_S), and every one of those belongs
+    // to P6 or later.
+    struct IpcTable {
+        // MOBILEGL_IPC_SERVER_PATH: where to find libMobileGLServer. P6 consumes it; P5
+        // lands the parse because t1's ctest ENVIRONMENT blocks and add_trace_replay_test's
+        // SPLIT variant already carry it, and an environment variable that nothing parses is
+        // indistinguishable from one that is parsed and ignored.
+        String ServerPath;
+        // MOBILEGL_IPC_RING_MB: SEG_CMD size. A RECORD MAY BE AT MOST HALF OF THIS
+        // (RingProducer::MaxRecordBytes), so 8 MiB caps one record at 4 MiB; R-10 makes the
+        // codec publish a max-record-bytes counter rather than assume that is enough.
+        Uint32 RingMb = 8;
+        // MOBILEGL_IPC_STAGE_MB: SEG_STAGE size. Every blob and every var-tail's bytes live
+        // here (R-10: no chunking in P5, so nothing may exceed it).
+        Uint32 StageMb = 32;
+        // MOBILEGL_IPC_SPIN_US: spin before parking on a doorbell, either direction.
+        Uint32 SpinUs = 50;
+        // MOBILEGL_IPC_PERSISTENT_BLOCK_KB: block granularity of the persistent-map push.
+        // 0 IS A NEGATIVE CONTROL, NOT "unlimited": it disables the push, and
+        // PersistentCoherentMapScenario must go RED under it (exit gate E3(a)).
+        Uint32 PersistentBlockKb = 64;
+        // MOBILEGL_IPC_ADOPT_TIER: 2 = emulate (client keeps the shadow and pushes), which
+        // is the only tier P5 implements and the reason persistent-map-push can be non-zero
+        // at all (R-6). 0 and 1 parse and are Fatal at use with "P11"; they exist now so the
+        // negative control has a spelling the day P11 writes it.
+        Uint32 AdoptTier = 2;
+        // MOBILEGL_IPC_VERB_BARRIER: 1 = the client blocks at every verb boundary until
+        // appliedSeq reaches its emitSeq (R-1). 0 is the negative control: it is EXPECTED to
+        // be red, because 31 of the 63 PipeInputs fields are still pulled from a live
+        // GLContext by the client's residual fill and a free-running queue lets the server
+        // read a FUTURE value of them.
+        Uint32 VerbBarrier = 1;
+        // MOBILEGL_IPC_STRICT_ERRORS: promote a BARRIER-PULLED field read - and, in a split
+        // build, the seven sticky forwards that are otherwise exempt - from "count it in
+        // rsp" to Fatal (R-7.3).
+        Bool StrictErrors = false;
+        // MOBILEGL_IPC_AUDIT: after a record retires, the server fills the SEG_STAGE bytes
+        // it referenced with 0xDD (R-2.5). This is the ONLY mechanical control that an
+        // inproc implementation did not quietly keep using a pointer past its lifetime.
+        Bool Audit = false;
+        // MOBILEGL_IPC_SERVER_AFFINITY: `auto` (the default, big-core detection borrowed
+        // from ShaderCompilePool), `off`, or an explicit CPU mask. Kept as the raw string
+        // because the resolved mask is logged by whoever starts the apply thread, and the
+        // string is what an operator typed.
+        String ServerAffinity = "auto";
+    };
+    extern IpcTable Ipc;
+#else
+    // The whole point: in a build without MG_Remote this folds at compile time, so
+    // `if (MG_Config::Transport != MG_Config::TransportMode::Monolith)` in Init.cpp is a
+    // discarded statement and the pull build gains no symbol, no branch and no byte.
+    inline constexpr TransportMode Transport = TransportMode::Monolith;
+#endif
 } // namespace MobileGL::MG_Config

MobileGL/ConfigLoader.cpp

@@ -8,9 +8,9 @@
 
 #include "Config.h"
 #if MOBILEGL_PIPE_PUSH
-// For kMGPipeSubsystemsMigratedAtP3a, the push build's PipePush default (the P2 constant
-// beside it is the phase-by-phase control, not the default). Push-only, so the pull
-// build's translation unit is unchanged.
+// For kMGPipeSubsystemsMigratedAtP4a, the push build's PipePush default (the P2 and P3a
+// constants beside it are the phase-by-phase controls, not the default). Push-only, so the
+// pull build's translation unit is unchanged.
 #include <MG_Pipe/MGPipe.h>
 #endif
 
@@ -25,6 +25,15 @@ namespace MobileGL::MG_Config {
     // Zero/default-initialized at static-init time (all fields have constexpr-friendly
     // defaults), so it is safe to read even if MG_ConfigLoader::Init has not run yet.
     FeaturesTable Features;
+#if MOBILEGL_BUILD_DISAGGREGATED
+    // Same contract, and for the same reason: MG_Backend::Init() reads Transport, and a
+    // build order that put it before MG_ConfigLoader::Init() must see Monolith rather than
+    // a torn enum. Defined only here - in a pull build Config.h makes Transport a constexpr
+    // and there is nothing to define.
+    TransportMode Transport = TransportMode::Monolith;
+    String TransportEndpoint;
+    IpcTable Ipc;
+#endif
 } // namespace MobileGL::MG_Config
 
 namespace MobileGL::MG_ConfigLoader {
@@ -252,9 +261,9 @@ namespace MobileGL::MG_ConfigLoader {
         // A push build with the knob unset runs every subsystem migrated so far, so the
         // shipped path is the one the gates measure; MOBILEGL_PIPE_PUSH=0 in the
         // environment is the all-subsystems-pull control that reproduces P1 exactly, and
-        // kMGPipeSubsystemsMigratedAtP2 (0x7f) is the phase-by-phase control - P3a's two
-        // subsystems off, everything P2 landed still on.
-        features.PipePush = QueryEnvUint64("MOBILEGL_PIPE_PUSH", MG_Pipe::kMGPipeSubsystemsMigratedAtP3a);
+        // kMGPipeSubsystemsMigratedAtP3a (0x1ff) is the phase-by-phase control - P4a's four
+        // subsystems off, everything P3a landed still on.
+        features.PipePush = QueryEnvUint64("MOBILEGL_PIPE_PUSH", MG_Pipe::kMGPipeSubsystemsMigratedAtP4a);
 #else
         // Meaningless in a pull build: there is nothing to push. Config.h documents 0 as
         // "pull everything" and that stays literally true.
@@ -297,12 +306,106 @@ namespace MobileGL::MG_ConfigLoader {
 #undef ENTRY
     }
 
+#if MOBILEGL_BUILD_DISAGGREGATED
+    // MOBILEGL_TRANSPORT = monolith | inproc | spawn | unix:<path> | pipe:<name>
+    // (ARCHITECTURE.md:583). Shaped after InitBackendType above: an exact-name table, then
+    // one fallback that names what it did instead. The two prefixed forms are the only
+    // reason this is not literally that function's ENTRY macro.
+    //
+    // spawn / unix: / pipe: PARSE AND THEN REFUSE. They are P6's, and the refusal is NAMED
+    // rather than silent, because the failure this avoids is a P6 lane that set
+    // MOBILEGL_TRANSPORT=spawn, fell back to monolith, and went green on the wrong arm.
+    // The mode is left at Monolith so nothing half-initializes.
+    inline void InitTransport() {
+        String value;
+        QueryEnvVariable("MOBILEGL_TRANSPORT", value, "monolith");
+        String lowered = value;
+        std::transform(lowered.begin(), lowered.end(), lowered.begin(),
+                       [](unsigned char c) { return static_cast<char>(std::tolower(c)); });
+
+        MG_Config::TransportEndpoint.clear();
+        if (lowered.empty() || lowered == "monolith") {
+            MG_Config::Transport = MG_Config::TransportMode::Monolith;
+            return;
+        }
+        if (lowered == "inproc") {
+            MG_Config::Transport = MG_Config::TransportMode::InProcess;
+            MGLOG_I("Config: MOBILEGL_TRANSPORT=inproc - the MGPipe record stream crosses a real "
+                    "ring to an apply thread");
+            return;
+        }
+        // The three P6 forms. Recognised precisely, so the diagnostic can say "not yet"
+        // rather than "unknown", which are different bugs on the operator's side.
+        if (lowered == "spawn" || lowered.compare(0, 5, "unix:") == 0 ||
+            lowered.compare(0, 5, "pipe:") == 0) {
+            MGLOG_E("Config: MOBILEGL_TRANSPORT='%s' names a transport P6 implements and P5 does "
+                    "not; staying on monolith. This run is NOT a split run.",
+                    value.c_str());
+            MG_Config::Transport = MG_Config::TransportMode::Monolith;
+            return;
+        }
+        MGLOG_W("Config: Ignoring invalid env variable MOBILEGL_TRANSPORT='%s'; expected "
+                "monolith|inproc|spawn|unix:<path>|pipe:<name>, using monolith",
+                value.c_str());
+        MG_Config::Transport = MG_Config::TransportMode::Monolith;
+    }
+
+    // The MOBILEGL_IPC_* family (Config.h IpcTable). Parsed unconditionally rather than only
+    // when Transport != Monolith: a knob that silently means nothing on one arm of an A/B is
+    // how an A/B stops being one, and the ranges below are the diagnostics.
+    inline void InitIpc() {
+        auto& ipc = MG_Config::Ipc;
+        QueryEnvVariable("MOBILEGL_IPC_SERVER_PATH", ipc.ServerPath, "");
+        // Both ring floors are 1 MiB, not 0: a ring caps ONE record at half its size, and
+        // the catalogue's largest fixed payload (MGPFramebufferState, 304 bytes) plus a
+        // create_shader_state archive already needs far more than a toy ring. The ceilings
+        // are sanity, not policy.
+        ipc.RingMb = QueryEnvUint32("MOBILEGL_IPC_RING_MB", 8, 1, 1024);
+        ipc.StageMb = QueryEnvUint32("MOBILEGL_IPC_STAGE_MB", 32, 1, 4096);
+        ipc.SpinUs = QueryEnvUint32("MOBILEGL_IPC_SPIN_US", 50, 0, 1000000);
+        // 0 is admitted ON PURPOSE and is the negative control of exit gate E3(a): it turns
+        // the persistent-map push OFF, and PersistentCoherentMapScenario must go red.
+        ipc.PersistentBlockKb = QueryEnvUint32("MOBILEGL_IPC_PERSISTENT_BLOCK_KB", 64, 0, 65536);
+        // 2 is the only tier P5 implements (R-6). 0 and 1 parse here and are refused at the
+        // point of use, which is where the "P11" in the message belongs.
+        ipc.AdoptTier = QueryEnvUint32("MOBILEGL_IPC_ADOPT_TIER", 2, 0, 2);
+        ipc.VerbBarrier = QueryEnvUint32("MOBILEGL_IPC_VERB_BARRIER", 1, 0, 1);
+        ipc.StrictErrors = QueryEnvFlag("MOBILEGL_IPC_STRICT_ERRORS");
+        ipc.Audit = QueryEnvFlag("MOBILEGL_IPC_AUDIT");
+        QueryEnvVariable("MOBILEGL_IPC_SERVER_AFFINITY", ipc.ServerAffinity, "auto");
+
+        if (MG_Config::Transport == MG_Config::TransportMode::Monolith) return;
+        // One line, on the arm where these numbers decide behaviour, because every one of
+        // them is a number a bug report has to quote.
+        MGLOG_I("Config: IPC ring=%uMiB stage=%uMiB spin=%uus persistent-block=%uKiB "
+                "adopt-tier=%u verb-barrier=%u strict=%d audit=%d affinity='%s'",
+                ipc.RingMb, ipc.StageMb, ipc.SpinUs, ipc.PersistentBlockKb, ipc.AdoptTier,
+                ipc.VerbBarrier, static_cast<int>(ipc.StrictErrors), static_cast<int>(ipc.Audit),
+                ipc.ServerAffinity.c_str());
+        if (ipc.VerbBarrier == 0) {
+            MGLOG_W("Config: MOBILEGL_IPC_VERB_BARRIER=0 is the R-1 NEGATIVE CONTROL and is "
+                    "expected to fail: the client still pulls 31 of 63 PipeInputs fields from a "
+                    "live GLContext, so an unbarriered queue lets the server read future values");
+        }
+        if (ipc.PersistentBlockKb == 0) {
+            MGLOG_W("Config: MOBILEGL_IPC_PERSISTENT_BLOCK_KB=0 is the E3(a) NEGATIVE CONTROL: "
+                    "the persistent-map push is OFF and a coherent-map scenario must go red");
+        }
+    }
+#endif
+
     void Init() {
         MGLOG_D("Loading configuration from environment variables...");
         InitializeAcceptedEnvVariables();
 
         InitBackendType();
         InitFeatures();
+#if MOBILEGL_BUILD_DISAGGREGATED
+        // After InitFeatures, so the one line InitIpc logs is the last word on this run's
+        // configuration, and before the accepted-env map is destroyed just below.
+        InitTransport();
+        InitIpc();
+#endif
 
         // Destroy the map since we won't need it anymore
         acceptedEnvVariablesMap.reset();

MobileGL/MG_Backend/DirectGLES/Managers.h

@@ -20,6 +20,11 @@
 #if MOBILEGL_PIPE_PUSH
 // P3a: the vertex-input payload views the handle arm of the VAO twin consumes.
 #include <MG_Pipe/MGPipeTypes.h>
+// P4a: the RECORDS the five re-keyed twins read instead of the frontend object. The readers
+// below hand back pointers to them, and MGPipeResourceRecord::PendingUpload is a nested type,
+// so a forward declaration would not do. Push-only, like everything else P4a adds to this
+// header, so the pull build's include graph is unchanged (D-P).
+#include <MG_Pipe/PipeApply.h>
 #endif
 
 namespace MobileGL::MG_Backend::DirectGLES {
@@ -428,6 +433,52 @@ namespace MobileGL::MG_Backend::DirectGLES {
             return nullptr;
         }
 
+        // P4a (D-B1): resolve-or-create BY THE HANDLE THE CALL CARRIED. This is the shape P3a
+        // already runs for the buffer family through BackendBufferResourceTable, lifted onto
+        // the five registries that still mint their own handles off a frontend lifetime id -
+        // the debt SlotTables.h records against itself at the top of that file.
+        //
+        // POINTER, not the reference GetOrCreate(StatePtr) returns, and that is deliberate:
+        // this call has THREE ways to decline and every one of them has to be visible to the
+        // caller rather than answered with a parked twin.
+        //   * the legacy arm is running, so there is no slot table to index;
+        //   * the slot is past the table's sanity bound (a corrupt 32-bit slot must not decide
+        //     a vector resize);
+        //   * the generation is BEHIND the live entry's. SlotTables.h:301-321 is the whole
+        //     argument: forward is a recycle and resets the twin, BACKWARD is refused, because
+        //     adopting it would destroy the incumbent LIVE twin's driver ids and then stamp the
+        //     slot back to the dead object's generation - the shape commit d7655247 fixed.
+        // The refusal is SILENT here and gets its release-build voice at the per-kind resolver
+        // in Managers.cpp, exactly as GetOrCreateBufferResourceForHandle gives P3a's.
+        BackendPtr* GetOrCreateByHandle(MG_Pipe::MGPipeHandle handle) {
+            if (!EsprytSlotTablesEnabled()) return nullptr;
+            if (MG_Pipe::MGPipeHandleIsNull(handle)) return nullptr;
+            if (handle.Slot >= SlotTable::kMaxHandleSlot) return nullptr;
+            const Uint32 liveGen = m_slotTable.LiveGenAt(handle.Slot);
+            if (liveGen != 0 && liveGen > handle.Gen) return nullptr;
+            return &m_slotTable.GetOrCreate(handle);
+        }
+
+        // The generation of the LIVE entry at this slot, or 0. It exists so a caller can
+        // DIAGNOSE, in a release build where MOBILEGL_ASSERT is inert, the refusal above
+        // performs silently.
+        Uint32 LiveGenAt(Uint32 slot) const {
+            if (!EsprytSlotTablesEnabled()) return 0;
+            return m_slotTable.LiveGenAt(slot);
+        }
+
+        // NO ReleaseByHandle HERE, AND THAT IS A DECISION (review M-4). The death half of
+        // GetOrCreateByHandle exists for a kind whose announcement is its own destroy CALL
+        // rather than the shared death notice - which is the BUFFER family
+        // (BackendBufferResourceTable::ReleaseByHandle, SlotTables.h, called from
+        // resource_destroy) and none of the five kinds this registry serves: every one of them
+        // dies through DestroyByLifetimeId below, because P4a adds no server-side destroy arm
+        // for a texture, a renderbuffer, a framebuffer, a sampler CSO or a shader CSO. v1
+        // declared one here anyway and it had no caller on either arm, which made its bound and
+        // its wording things nobody would exercise until P5. The one-line wrapper comes back in
+        // the commit that gives it a caller; SlotTable::ReleaseByHandle underneath is untouched
+        // and is what SanityTest drives directly.
+
         // P2 step e2. STATIC, because a death notice is about an object and not about a
         // registry instance: it is answered by EVERY table of this kind that exists - this
         // registry's own, and any by-value copy of it a fixture or a context reset is holding
@@ -552,6 +603,121 @@ namespace MobileGL::MG_Backend::DirectGLES {
     using TwinRegistry = StateBackendObjectRegistry<StateObject, BackendObject>;
 #endif
 
+#if MOBILEGL_PIPE_PUSH
+    // ---- P4a (D-K3): one arm resolver per family, beside BufferImpl's two ----
+    //
+    // Four bits and therefore four resolvers, for P3a's reason one level out: a framebuffer
+    // path that regressed, a texture path that regressed, a sampler path that regressed and a
+    // program path that regressed are four different findings, and clearing one must not
+    // disarm the other three.
+    //
+    // THE RESOLUTION IS LAZY, at the first use, and never at bring-up. Backend context creation
+    // runs inside eglMakeCurrent and the integration harness pre-flights exactly that sequence
+    // in a FORKED CHILD; a child that dies on a signal is reported as "no usable GPU" and every
+    // scenario in the lane is SKIPPED - the lane goes green having run nothing, on the very
+    // pair of env vars the A/B is driven with, which is what ROADMAP.md:7 forbids. So a stop
+    // has to land in a test body, i.e. at the first lookup. That is what the inline latches
+    // below give: a guard-variable load and a perfectly-predicted branch per consult, and the
+    // arm dispatch folds into the caller (SlotTables.h's EsprytSlotTablesEnabled argument
+    // verbatim - every one of these is consulted on the per-draw path).
+    //
+    // ALL FOUR CAN REACH NoArm and all four STOP there rather than skipping green, because
+    // every one of the four legacy arms is compiled under MOBILEGL_PIPE_LEGACY_MEMOS:
+    //   framebuffer  - the four g_fboSynced* arrays and StampSyncedFBO;
+    //   texture      - the twin's m_prevTextureInfo / m_syncedContentVersion cheap-gate trio;
+    //   samplers     - UnitSamplerLookupMemo's WeakPtr arm and SamplerPassMemo's raw
+    //                  BackendSamplerObject* rows;
+    //   programs     - g_programTwinLookupMemo.
+    //
+    // THREE OF THEM CARRY A DEPENDENCY (MGPipe.h, D-K2) and it is diagnosed and REFUSED here
+    // rather than half-run, the bit-8-requires-bit-7 shape ResolveVertexInputSubsystemArm
+    // already ships: bit 11 requires bit 10, bit 9 requires bit 10, bit 10 requires bit 7. The
+    // mirror pairs (10 without 11, 10 without 9, 7 without 10) are all FINE and are said so out
+    // loud, because an unreachable branch that says something different is how the reachable
+    // one drifts. Bit 12 depends on nothing: a ShaderCso handle names no texture and no buffer.
+    //
+    // ResolveFramebufferSubsystemArm additionally carries D-C3's bring-up refusal: the wire
+    // array is MGPFramebufferState::Color[8] and GetDynamicParameters().MaxColorAttachments is
+    // the driver's RAW ES cap, which is not clamped to 8 on this path. A driver reporting more
+    // would silently truncate the record, so the bit is refused with one MGLOG_E naming the cap
+    // and the legacy arm runs. Widening the payload is a wire change nobody has evidence for;
+    // truncating silently is the bug class this phase is closing.
+    Bool ResolveFramebufferSubsystemArm();
+    Bool ResolveTextureResourceSubsystemArm();
+    Bool ResolveSamplerSubsystemArm();
+    Bool ResolveProgramSubsystemArm();
+
+    inline Bool FramebufferSubsystemEnabled() {
+        static const Bool enabled = ResolveFramebufferSubsystemArm();
+        return enabled;
+    }
+    inline Bool TextureResourceSubsystemEnabled() {
+        static const Bool enabled = ResolveTextureResourceSubsystemArm();
+        return enabled;
+    }
+    inline Bool SamplerSubsystemEnabled() {
+        static const Bool enabled = ResolveSamplerSubsystemArm();
+        return enabled;
+    }
+    inline Bool ProgramSubsystemEnabled() {
+        static const Bool enabled = ResolveProgramSubsystemArm();
+        return enabled;
+    }
+
+    // ---- P4a: what the twins read INSTEAD of the frontend object ----
+    //
+    // One reader per record kind, all const, all null-on-miss, and all bounds-checked against
+    // the applier's own dense table rather than against a constant: a slot at or above the
+    // table's size simply has no record, which is the same answer as "not live" and is not a
+    // protocol error on THIS side (the applier already refused and counted the call that would
+    // have created it - PipeApply.h's RefusedObjectCalls).
+    //
+    // A NULL ANSWER IS NOT A FALL-BACK TO THE FRONTEND. On a family's handle arm, quietly
+    // reaching into the frontend object again would hide a missing record behind a picture that
+    // still looks right, which is exactly what the subsystem A/B exists to expose
+    // (MarkBufferGpuWritten's note, P3a). Every caller below either declines the work with a
+    // named MGLOG_E_ONCE or runs its family's LEGACY arm, decided by the family latch and
+    // never per record.
+    //
+    // The returned pointer is into a Vector the applier may grow, so it is valid only until the
+    // next applier call - the same rule the legacy arm's map-into pointers carried, and every
+    // caller here reads what it needs and lets go.
+    const MG_Pipe::MGPipeResourceRecord* PipeTextureRecordForHandle(MG_Pipe::MGPipeHandle res);
+    const MG_Pipe::MGPipeResourceRecord* PipeRenderbufferRecordForHandle(MG_Pipe::MGPipeHandle res);
+    const MG_Pipe::MGPipeSamplerCsoRecord* PipeSamplerCsoRecordForHandle(MG_Pipe::MGPipeHandle cso);
+    const MG_Pipe::MGPipeSamplerViewRecord* PipeSamplerViewRecordForHandle(MG_Pipe::MGPipeHandle view);
+    // ShaderCso is the one kind whose slot space is split in two on the CLIENT side - the
+    // composite band lives in its own dense table so a single program-pipeline composite does
+    // not grow a 983040-entry vector (contract D13). The server never learns a handle is a
+    // composite: this reader hides the split behind one lookup, exactly as the wire does.
+    const MG_Pipe::MGPipeShaderCsoRecord* PipeShaderCsoRecordForHandle(MG_Pipe::MGPipeHandle cso);
+
+    // The pending-upload entry the applier accumulated for this (uploadTarget, level) of this
+    // texture record, or null (D-D5). SERVER-SIDE STATE, and that is the whole point: the
+    // client clears its own dirty flags at EMISSION for the levels the applier accepted, while
+    // Espryt's upload loop has bail arms - an incomplete texture returns early, a multisample
+    // target refreshes and skips - that today leave the frontend flag set. A naive move of the
+    // clear to the client would lose exactly those texels. The set survives any number of
+    // bails; ConsumePipeTextureUpload below is called ONLY where the level actually uploaded.
+    //
+    // `uploadTarget` is static_cast<Uint16>(MobileGL::TextureUploadTarget) - the HALF, not the
+    // packed field. The stored key is MGPSubData::Target whole (low byte MGPipeResourceTarget,
+    // high byte TextureUploadTarget, ID-12) and both functions decode it with
+    // MGPipeSubDataUploadTargetOf; they are the only two places this package compares it.
+    const MG_Pipe::MGPipeResourceRecord::PendingUpload* FindPipeTextureUpload(
+        const MG_Pipe::MGPipeResourceRecord& record, Uint16 uploadTarget, Uint16 level);
+    void ConsumePipeTextureUpload(MG_Pipe::MGPipeHandle res, Uint16 uploadTarget, Uint16 level);
+
+    // THE SERVER'S OWN RE-DIRTY, armed in the applier's set instead of in the frontend's model
+    // (esprytobj review M-1). `packedTarget` is a full MGPSubData::Target built with
+    // MGPipePackSubDataTarget, because the entry this writes has to be indistinguishable from
+    // one the client emitted. Whole-level, no regions, merged with any entry already there;
+    // false (and one named log line) when the applier's pending set is at its bound. The three
+    // server-side MarkStorageDirty sites are enumerated at the definition.
+    Bool RearmPipeTextureLevelUpload(MG_Pipe::MGPipeHandle res, Uint16 packedTarget, Uint16 level,
+                                     const MG_Pipe::MGPBox& wholeLevel);
+#endif
+
     namespace BufferImpl {
         const GLenum TempBufferTarget = GL_ARRAY_BUFFER;
 
@@ -1514,6 +1680,61 @@ namespace MobileGL::MG_Backend::DirectGLES {
             // single-level texture with a mipmapping filter), and an incomplete texture samples
             // (0, 0, 0, 1) rather than its contents.
             Bool m_forceSamplerResync = false;
+#if MOBILEGL_PIPE_PUSH
+            // ---- P4a's handle arm: the two prologues that decide WHETHER there is work and
+            // WHERE the values come from. Both answer null for "nothing to do", which covers
+            // three cases the caller treats identically and the callee names individually in
+            // the log: the record's serial has not moved, this texture has no record at all,
+            // or its params name a sampler CSO the applier does not hold.
+            //
+            // NEITHER FALLS BACK TO THE FRONTEND. On this arm the texture family is switched
+            // over, and quietly re-reading the object would hide a missing record behind a
+            // picture that still looks right - which is precisely what the subsystem A/B exists
+            // to expose (MarkBufferGpuWritten's note, P3a).
+            const SamplerParameters* ResolvePushedBuiltinSampler(
+                const SharedPtr<MG_State::GLState::ITextureObject>& stateTextureObject);
+            // Hands back the whole RECORD rather than its Params, because the parameter push
+            // reads two things from beside them: Desc.InternalFormat, which decides the two
+            // channel-widening swizzle compositions, and Params.BuiltinSampler, which is where
+            // the border colour lives (it is sampler state, GL 4.6 table 23.18, and P4a does
+            // not duplicate it onto MGPTextureParams).
+            const MG_Pipe::MGPipeResourceRecord* ResolvePushedTextureParams(
+                const SharedPtr<MG_State::GLState::ITextureObject>& stateTextureObject);
+
+            // ---- P4a's handle arm (D-B3). Three server-owned serials that REPLACE, on their
+            // own arm, the six frontend-version memos above; the legacy members stay beside
+            // them under MOBILEGL_PIPE_LEGACY_MEMOS because ARCHITECTURE.md:369 keeps the
+            // pre-handle arm compiled through P3a/P4a, and because clearing the family's bit
+            // has to run the pre-handle arm rather than a half-migrated one.
+            //
+            // Inside the guard, so the PULL build's BackendTextureObject is byte-for-byte the
+            // pre-P4a object and G1's admitted-resize set stays empty (D-P).
+            //
+            // 0 is never a real serial - the applier's counters start at 1 and only ever
+            // advance, including across a make-current (PipeApply.cpp's three-way argument) -
+            // so a zeroed memo is a guaranteed miss and a fresh twin owes a full sync.
+
+            // The resource record's Serial at the last completed mipmap sync. It replaces the
+            // whole cheap-gate trio (m_syncedShapeContextId / m_syncedShapeGeneration /
+            // m_syncedShapeParamsVersion) AND m_syncedContentVersion: the applier bumps it on
+            // every respecify and every sub-data it applies to this resource, which is exactly
+            // the union those four covered, without the coarse "any texture's churn re-opens
+            // every gate" behaviour the sampling-resolution generation had.
+            Uint64 m_syncedResourceSerial = 0;
+            // The record's ParamsSerial at the last SyncTextureParamsToBackend. Replaces
+            // m_syncedTextureParamsVersion; MGPTextureParams::ForceResync replaces
+            // m_forceTextureParamsResync and is consumed the same way - read, acted on, and
+            // NOT written back, because the client never clears a server flag and the server
+            // never clears the client's (D-E2, the D-D5 inversion applied to two bits).
+            Uint64 m_syncedParamsSerial = 0;
+            // The BuiltinSampler CSO record's Serial at the last SyncBuiltinSamplerToBackend,
+            // plus the handle it was read through - a texture whose params name a DIFFERENT
+            // CSO than last time has had its sampling state replaced wholesale even if the new
+            // CSO's serial happens to match, which is a real sequence under content addressing
+            // (two textures sharing one CSO, then one of them diverging).
+            Uint64 m_syncedBuiltinSamplerSerial = 0;
+            MG_Pipe::MGPipeHandle m_syncedBuiltinSampler = MG_Pipe::kMGPipeNullHandle;
+#endif
         };
 
         void ActivateTextureUnit(Uint unit);
@@ -1606,11 +1827,64 @@ namespace MobileGL::MG_Backend::DirectGLES {
             // mismatch means some backend texture id was re-minted since, and any of this
             // twin's attachment points may still hold the dead id even though the frontend
             // attachment versions match - so the walk re-attaches everything first.
+            //
+            // SERVER-OWNED AND IT SURVIVES P4a (D-B3). It answers "did *I* re-mint a driver
+            // texture id", which no client-side version can answer; dropping it would
+            // reintroduce exactly the class of bug commit d7655247 fixed on the buffer side.
             Uint64 m_syncedBackendIdGeneration = 0;
+#if MOBILEGL_PIPE_PUSH
+            // P4a (D-C4): MGPFramebufferState::ContentHash as of this twin's last sync, PER
+            // TARGET IT WAS SYNCED AS, and it is the second of the hash's two jobs - "the server's
+            // render-pass memo key, and the CLIENT's emission suppressor". It replaces
+            // m_syncedFrontendAttachmentVersions AS A KEY (the array stays: it is what the
+            // legacy arm compares, and it is the mechanism the handle arm re-arms through).
+            //
+            // The hash covers every field the record carries - Fbo included, so a recycled
+            // framebuffer handle whose successor happens to carry an identical attachment set
+            // can never be suppressed against its predecessor, and DrawBuffers[8] included, so
+            // a suppressed record provably means the draw-buffer array did not move, which
+            // provably means the fragColor broadcast count did not move.
+            //
+            // PER TARGET rather than one, and it stays that way under ID-19's per-OBJECT record:
+            // there is now ONE record for this framebuffer, but syncing it as Draw and syncing it
+            // as Read do different work (glDrawBuffers and the four cross-object masks are
+            // Draw-only, glReadBuffer is Read-only), so "I have already applied this record" is a
+            // per-target claim and one memo would let the second target skip work the first never
+            // did. 0 is never a live hash (a computed 0 is remapped to 1 by the client's
+            // suppressor), so a zeroed memo is a guaranteed miss.
+            Array<Uint64, SizeT(FramebufferTarget::FramebufferTargetCount)> m_syncedRecordHashes = {0};
+#endif
         };
 
         extern TwinRegistry<MG_State::GLState::FramebufferObject, BackendFramebufferObject, MG_Pipe::MGPipeKind::Framebuffer>
             g_backendFramebufferObjects;
+
+#if MOBILEGL_PIPE_PUSH
+        // P4a (D-C2 as corrected by ID-19): the applier's record for THE FRAMEBUFFER OBJECT this
+        // handle names, or null.
+        //
+        // v1 asked the applier for its two BOUND-target working records and answered null unless
+        // one of them happened to name this twin - which meant every DSA entry point
+        // (BlitNamedFramebuffer, the four ClearNamedFramebuffer*) drove a framebuffer that is
+        // bound to neither target, found no record, declined, and then had the clear or blit
+        // issued against a driver FBO that never got its attachments. The record is now keyed by
+        // the framebuffer HANDLE (MGPipeApplierState::FramebufferRecords, wire v3), so a record
+        // that comes back is this framebuffer's by construction and it comes back whether the
+        // object is bound to Draw, to Read, to both or to neither. A null here means "no emission
+        // has ever described this framebuffer, or the handle's generation is stale" - both of
+        // them seam defects on an integrated tree, never a binding question.
+        //
+        // `fbo` is the handle the caller resolved for this twin; passing it in rather than
+        // resolving it here keeps the monolith-glue lookup at one site per sync.
+        const MG_Pipe::MGPFramebufferState* PushedFramebufferRecord(MG_Pipe::MGPipeHandle fbo);
+
+        // THE BINDING QUESTION, WHICH IS NOW A DIFFERENT QUESTION FROM THE DESCRIPTION (ID-19(d)):
+        // "is the framebuffer this handle names the one bound to `target`". One array compare
+        // against MGPipeApplierState::BoundFramebuffer, never a record lookup - a Named record
+        // describes an object without claiming any binding for it, so asking the record would
+        // give the wrong answer by construction.
+        Bool PushedFramebufferIsBoundTo(FramebufferTarget target, MG_Pipe::MGPipeHandle fbo);
+#endif
         // True when the read buffer names a fixed-point (norm/snorm) attachment that the
         // backend actually stores in a floating-point format. GL clamps a read from a
         // fixed-point colour buffer to [0,1] (GL_CLAMP_READ_COLOR defaults to
@@ -1704,6 +1978,16 @@ namespace MobileGL::MG_Backend::DirectGLES {
         // the driver FBO would keep the deleted texture name attached forever. The
         // SyncCurrentFBO gate compares this generation (below) to re-enter the sync,
         // and each twin re-arms its per-attachment memo on a mismatch (SyncToBackend).
+        //
+        // AND WHENEVER AN ATTACHABLE OBJECT'S DRIVER STORAGE IS REDEFINED IN PLACE (P4a fable
+        // seam F-3): a mutable texture regenerated on the same id, a renderbuffer re-storaged
+        // on the same id. The id did not move, but the four cross-object masks SyncToBackend
+        // computes from the attachment's format did, and nothing else the FBO memo reads sees
+        // a respecify of an attached object. So "did I change something under an attachment
+        // point that no frontend version can tell the framebuffer about" is what this counts,
+        // and the re-mint is one case of it. The in-place bumps are compiled under
+        // MOBILEGL_PIPE_PUSH: G1 keeps the pull library byte-identical to the P4a baseline,
+        // so the pull build keeps the pre-P4a hole until they land on dev on their own.
         extern Uint64 g_attachmentBackendIdGeneration;
         // What g_attachmentBackendIdGeneration was when SyncCurrentFBO last stamped each
         // target; part of the synced tuple above.
@@ -1718,6 +2002,27 @@ namespace MobileGL::MG_Backend::DirectGLES {
         // GL_FRAMEBUFFER binds both targets.
         void BindFramebufferId(GLenum fbTarget, Uint id);
         Uint CurrentFramebufferBinding(FramebufferTarget target);
+#if MOBILEGL_PIPE_PUSH
+        // THE HANDLE ARM'S OWN FRAMEBUFFER MEMOS, AND THEY ARE PACKAGE E's STORAGE
+        // (DirectGLES.cpp: g_fboSyncedSerials, g_fboRecordsTrusted). E's review MAJOR-4 handed
+        // this to D because InvalidateFramebufferBindingCache is in THIS file and has three
+        // callers E cannot reach - MG_Test/SanityTest.cpp's ScopedStateGuardMocks::ResetShadows
+        // and ScopedBackendTwinMocks' constructor and destructor - which clear the pre-handle
+        // trio and would leave the handle-arm memos claiming a target is synced across a GLES
+        // function-table swap. Calling it from INSIDE InvalidateFramebufferBindingCache is what
+        // makes forgetting impossible, and that call is written below.
+        //
+        // IT IS GATED, AND HERE IS THE HANDSHAKE, because the definition is `static` in E's file
+        // on the tree this package was built against (esprytdraw v2, DirectGLES.cpp:2789) and an
+        // internal-linkage function cannot be called from Managers.cpp. E's verification round
+        // drops that one keyword; D's verification round flips this constant to 1, in this file,
+        // one line. Neither side can do it silently: the flip has no other reader and the
+        // declaration below has no other definition.
+#define MOBILEGL_ESPRYT_FBO_HANDLE_ARM_MEMOS_LINKED 0
+#if MOBILEGL_ESPRYT_FBO_HANDLE_ARM_MEMOS_LINKED
+        void InvalidateFramebufferHandleArmMemos();
+#endif
+#endif
         void InvalidateFramebufferBindingCache();
         // A driver framebuffer id is about to be deleted: ES reverts every target that
         // currently binds it to 0, so the binding shadow has to follow or the next
@@ -2009,6 +2314,22 @@ namespace MobileGL::MG_Backend::DirectGLES {
             // stale as one built before a relink - while the sampler half, which really is
             // re-issued per draw, needs nothing of the sort.
             Uint32 GetSyncedImageUnitVersion() const { return m_syncedImageUnitVersion; }
+#if MOBILEGL_PIPE_PUSH
+            // P4a (D-B3, D-H5): the ShaderCso record's Serial this backend program was built
+            // from. It is what the draw path's nine-clause rebuild condition reads on the handle
+            // arm INSTEAD OF the two frontend versions above - one server-owned counter that
+            // moves on every create_shader_state the applier applies to this handle, including a
+            // RE-create on the same handle, which is how a relink travels (Gen moves only on slot
+            // reuse, never on a respecify).
+            //
+            // THE CLAUSE COUNT DOES NOT SHRINK, and a brief that treated create_shader_state as
+            // self-contained would produce a per-draw rebuild: the other eight inputs - the draw
+            // FBO's snorm/unorm clamp masks, the fragColor broadcast count, the storage-block
+            // binding signature, the atomic-counter set, the live image formats and the patch
+            // parameters - are all still specialised at the verb, from state this backend holds.
+            // 0 means "never stamped", which is a guaranteed miss (applier serials start at 1).
+            Uint64 GetSyncedShaderCsoSerial() const { return m_syncedShaderCsoSerial; }
+#endif
             // Whether the (unit, bound format) pairs this program's FORMAT-LESS image uniforms
             // resolve to are still the ones its ESSL was generated against.
             //
@@ -2108,6 +2429,11 @@ namespace MobileGL::MG_Backend::DirectGLES {
             BufferImpl::UboRingAllocation m_globalUboRingAllocation;
             Uint32 m_syncedLinkVersion = ~0u;
             Uint32 m_syncedImageUnitVersion = ~0u;
+#if MOBILEGL_PIPE_PUSH
+            // P4a's replacement for the two above on the handle arm; see GetSyncedShaderCsoSerial.
+            // Push-only, so the pull build's object is byte-for-byte the pre-P4a one (D-P).
+            Uint64 m_syncedShaderCsoSerial = 0;
+#endif
             // Image units addressed by the program's FORMAT-LESS image uniforms, and the digest
             // of the (unit, format) pairs the generated ESSL baked. Empty/0 for every program
             // that declares a format on all of its images, which is the overwhelming majority -
@@ -2211,7 +2537,32 @@ namespace MobileGL::MG_Backend::DirectGLES {
             ~BackendSamplerObject();
             BackendSamplerObject(const BackendSamplerObject&) = delete;
             BackendSamplerObject& operator=(const BackendSamplerObject&) = delete;
+#if MOBILEGL_PIPE_PUSH
+            // THE SAMPLER CSO HANDLE IS CARRIED BY THE CALLER, and it has to be, because a
+            // SamplerCso is CONTENT-ADDRESSED on the client (D-F1) while this twin is keyed on
+            // the frontend OBJECT. g_backendSamplerObjects mints a SamplerCso slot off the
+            // SamplerObject's lifetime id - that handle is this twin's identity and is what
+            // FindByHandle memos index - but the client's cache allocates its handles by
+            // CONTENT (MGPipeSlots().Allocate, SamplerEmit.h), so no create_sampler_state ever
+            // lands at the identity handle and looking a record up by it can only ever miss.
+            // The carried fact that DOES name the right record is the applier's own
+            // MGPipeApplier().BoundSamplerStates[unit], which the client writes per unit at
+            // bind_sampler_states; the caller that knows the unit passes it here.
+            //
+            // Defaulted so a caller that has no unit - the backend's OWN raw-depth-fetch
+            // sampler (DirectGLES.cpp:217), a SamplerObject the client has never seen and for
+            // which no record can exist - keeps working: that arm reads the object, which is
+            // the authority for server-owned state. An APPLICATION sampler reaching here
+            // without a handle is the E-side call-site gap and says so once.
+            //
+            // Push-only spelling on purpose: a defaulted parameter is still part of the
+            // signature, so widening it unconditionally would rename this symbol in the PULL
+            // build and P4a's admitted-change set is EMPTY (D-P/G1).
+            void SyncToBackend(const SharedPtr<MG_State::GLState::SamplerObject>& stateSamplerObject,
+                               MG_Pipe::MGPipeHandle pushedCso = MG_Pipe::kMGPipeNullHandle);
+#else
             void SyncToBackend(const SharedPtr<MG_State::GLState::SamplerObject>& stateSamplerObject);
+#endif
             void Bind(Uint unit);
             Uint GetBackendSamplerId() const;
 
@@ -2221,6 +2572,19 @@ namespace MobileGL::MG_Backend::DirectGLES {
             Bool m_isInitialized = false;
             SamplerParameters m_cacheSamplerParameters;
             Uint16 m_syncedSamplerVersion = 0;
+#if MOBILEGL_PIPE_PUSH
+            // P4a (D-B3): the SamplerCso record's Serial at the last completed sync. It replaces
+            // m_syncedSamplerVersion, which stays beside it because the pre-handle arm compiles
+            // under MOBILEGL_PIPE_LEGACY_MEMOS through P3a/P4a (ARCHITECTURE.md:369).
+            //
+            // The two are not interchangeable and that is the point: the frontend version is per
+            // OBJECT, while the serial is per CONTENT-ADDRESSED CSO, and two frontend samplers
+            // with identical parameters share one CSO and therefore one serial - so under the
+            // handle arm the second of them costs no driver call at all.
+            //
+            // Push-only, so the pull build's object is byte-for-byte the pre-P4a one (D-P).
+            Uint64 m_syncedSamplerSerial = 0;
+#endif
         };
 
         void UnbindSampler(Uint unit);
@@ -2229,8 +2593,108 @@ namespace MobileGL::MG_Backend::DirectGLES {
             g_boundSamplersCache;
         extern TwinRegistry<MG_State::GLState::SamplerObject, BackendSamplerObject, MG_Pipe::MGPipeKind::SamplerCso>
             g_backendSamplerObjects;
+
+#if MOBILEGL_PIPE_PUSH
+        // P4a FABLE SEAM F-4: THE TWIN FOR A CONTENT-ADDRESSED SamplerCso HANDLE.
+        //
+        // bind_sampler_states carries, per unit, the handle of a CSO the client allocated BY
+        // CONTENT (SamplerEmit.h: MGPipeSlots().Allocate with no lifetime id), while every twin
+        // in g_backendSamplerObjects was minted off a SamplerObject's lifetime id - two disjoint
+        // slot families out of one allocator. So `g_backendSamplerObjects.FindByHandle(
+        // BoundSamplerStates[unit])` (the record arm of BindCurrentUnitSamplers, E's S4) could
+        // never find a twin, the record arm bound nothing on every draw, and every glBindSampler
+        // reached the driver only through the pre-handle program pass - S-1's confusion one
+        // loop over, and exactly what SamplerEmit.h:201-205 forbids ("a backend must NOT key a
+        // sampler twin on a SamplerObject's lifetime id; the twin's life is
+        // create_sampler_state -> delete_sampler_state").
+        //
+        // This is the twin keyed the way the record is: resolved-or-created AT THE CSO HANDLE
+        // (GetOrCreateByHandle, the same slot table, a slot the identity family can never hold)
+        // and synced from the record it names, serial-gated. Two callers bind it - the record
+        // arm of BindCurrentUnitSamplers and the program pass's sampler override - so the two
+        // cannot ping-pong the unit between an identity twin and a CSO twin. Its death is the
+        // slot's recycle: the client's LRU eviction drops the record and frees the slot, and
+        // the next handout at that slot arrives with a moved generation, which GetOrCreate(
+        // handle) answers by resetting the twin (the driver sampler goes with it). A twin for
+        // an evicted CSO therefore lives until its slot is reused - bounded by the cache's
+        // capacity, never by draw count - and there is no delete_sampler_state hook to retire it
+        // earlier; the ops table carries none for this kind.
+        //
+        // Null, loudly, when the handle names no record (a client seam) or cannot be adopted
+        // (a generation behind the slot's live entry); null silently for the null handle. The
+        // pre-handle arm - a twin keyed on the frontend object - is untouched and still serves
+        // the raw-depth-fetch sampler and every caller that carries no handle.
+        BackendSamplerObject* ResolveSamplerCsoTwin(MG_Pipe::MGPipeHandle cso);
+#endif
     } // namespace SamplerImpl
 
+#if MOBILEGL_PIPE_PUSH
+    namespace SamplerViewImpl {
+        // P4a (D-F2/D-F3): the SIXTH Espryt twin table, and the only one of the six whose kind
+        // has no frontend object at all. MobileGL has no sampler-view class: GL binds a texture
+        // to a unit and the sampler uniform's type, the mipmap-completeness predicates and
+        // IsUndefinedDefaultTexture decide what the shader sees. Gallium's one-view-per-slot IS
+        // that resolved form, the resolution moves to the CLIENT (ARCHITECTURE.md:206), and
+        // create_sampler_view carries the restrictions the resolution had to read.
+        //
+        // So this twin owns NO DRIVER ID. There is nothing in ES to create for a view; the id
+        // the unit binds is the texture's, and it lives on BackendTextureObject. What this twin
+        // is, is the server's MEMO of one resolved view: the record it was built from, keyed on
+        // that record's serial, plus the two BACKEND-SPECIFIC POST-PROCESSINGS
+        // ARCHITECTURE.md:206 keeps on the server and which act on the already-resolved set.
+        // Espryt's is the raw-depth-fetch sampler substitution; Magma's feedback-loop detection
+        // is its own and is not here.
+        //
+        // A twin with no driver id still earns a table: it is what turns "re-derive the
+        // substitution decision for every sampled unit of every draw" into one serial compare,
+        // and it is the slot space the client's per-texture SamplerViewCso handle indexes.
+        // There is deliberately no destructor: nothing here owns a GPU object, so the teardown
+        // sentinel's whole reason (a twin destructor must not call into an unloaded driver)
+        // does not apply and the default one is correct in every teardown order.
+        struct BackendSamplerViewObject {
+            // The view record as last synced, verbatim. Reading it here rather than re-asking
+            // the applier is what lets a caller hold the twin across another applier call.
+            MG_Pipe::MGPSamplerView View{};
+            // The applier record's Serial this memo was built from. 0 = never synced, and 0 is
+            // never a real serial (the applier's counters start at 1), so a zeroed memo is a
+            // guaranteed miss.
+            Uint64 SyncedSerial = 0;
+            // Espryt's post-processing, decided from the RESOLVED set: the view's
+            // InternalFormat answers IsDepthFormatInternalFormat and the sampler CSO record's
+            // SamplerParameters answer compareMode / minFilter / mipmapMode / magFilter. The
+            // decision is re-derived when either serial moves; the sampler serial is kept
+            // beside it so a sampler mutation alone re-derives it.
+            Uint64 SyncedSamplerSerial = 0;
+            Bool NeedsRawDepthFetchSampler = false;
+        };
+
+        // Handle-keyed ONLY, exactly like P3a's BackendBufferResourceTable: the StateObject
+        // parameter names ITextureObject because the template names one and because the view is
+        // minted off the TEXTURE's lifetime id (D-F2: one view per ITextureObject), which is
+        // what makes HandleOf below resolve at all. Not one member that would dereference it is
+        // instantiated - no Find(StateObject*), no ForEachLive - and the handle overloads never
+        // look at it.
+        using BackendSamplerViewTable = BackendSlotTable<MG_State::GLState::ITextureObject,
+                                                        BackendSamplerViewObject,
+                                                        MG_Pipe::MGPipeKind::SamplerViewCso>;
+        extern BackendSamplerViewTable g_backendSamplerViews;
+
+        // Resolve-or-create / resolve-only by the handle the call carried. Neither touches
+        // MGPipeSlots(): the handle ARRIVED, already minted by the side that owns minting.
+        BackendSamplerViewObject* GetOrCreateSamplerViewForHandle(MG_Pipe::MGPipeHandle view);
+        BackendSamplerViewObject* FindSamplerViewForHandle(MG_Pipe::MGPipeHandle view);
+
+        // MONOLITH GLUE, and named as such, the HandleOfBuffer shape: the SamplerViewCso handle
+        // of a texture this backend is looking at through a frontend object. Legal only because
+        // the view is minted off the texture's own lifetime id; under a real split neither the
+        // object nor its lifetime id exists on this side and the handle has to arrive in the
+        // payload (which, for every path P4a switches over, it does - this is for the paths
+        // P3b/P4b still owns).
+        MG_Pipe::MGPipeHandle HandleOfSamplerViewForTexture(
+            const MG_State::GLState::ITextureObject* textureObject);
+    } // namespace SamplerViewImpl
+#endif
+
     namespace RenderbufferImpl {
         class BackendRenderbufferObject {
         public:
@@ -2252,6 +2716,20 @@ namespace MobileGL::MG_Backend::DirectGLES {
             Int m_cacheWidth = 0;
             Int m_cacheHeight = 0;
             Int m_cacheSamples = 0;
+#if MOBILEGL_PIPE_PUSH
+            // P4a (D-D2/D-B3): the resource record's Serial at the last completed allocation.
+            // It replaces the four-field cache above AS A GATE - the four members stay, because
+            // they are also what the legacy arm compares and what the twin reports about the
+            // storage it actually holds - and it closes the publication hole D-D2 names:
+            // RenderbufferObject::{SetInternalFormat, AllocateStorage, SetSamples} bump no
+            // version and raise no notice, so `glBindRenderbuffer; glRenderbufferStorage(new)`
+            // on an ALREADY-ATTACHED renderbuffer moved nothing the framebuffer bit could see.
+            // The client now emits resource_respecify straight from those three mutators, the
+            // applier bumps this serial, and one compare here sees it.
+            //
+            // Push-only, so the pull build's object is byte-for-byte the pre-P4a one (D-P).
+            Uint64 m_syncedResourceSerial = 0;
+#endif
         };
 
         extern TwinRegistry<MG_State::GLState::RenderbufferObject, BackendRenderbufferObject, MG_Pipe::MGPipeKind::Renderbuffer>

MobileGL/MG_Backend/DirectVulkan/Renderer/MagmaPipeArms.h

@@ -194,10 +194,115 @@ namespace MobileGL::MG_Backend::DirectVulkan {
     //
     // Off by default (Config.h), set only by the HandleRecycle AbaControl ctest lanes, and
     // #if MOBILEGL_PIPE_PUSH throughout, so no shipping pull build can even parse it.
+    // P4a (BRIEF-P4A.md D-I2, G8): WHICH KINDS THIS ANSWER COVERS, and it is not "all of them".
+    //
+    // P4a mints six more client-side kinds - Texture, Renderbuffer, Framebuffer, SamplerCso,
+    // SamplerViewCso and ShaderCso - and requires the ABA control to defeat "the identity half
+    // of P4a's memo keys as well", because a control that only defeats the guards a phase
+    // RETIRED says nothing about the key that phase SHIPS.
+    //
+    // On Magma there is no such key to defeat, and that is a fact about the roadmap rather than
+    // an omission here. MagmaPipeIdentityTables below mints exactly TWO kinds,
+    // VertexElementsCso and Buffer; a texture, a framebuffer, a sampler, a view and a program
+    // are all still reached from their frontend objects on this backend, and moving them onto
+    // handles is P7's work (ROADMAP.md:24 - "Magma anything"; P4a leaves MG_Backend/DirectVulkan
+    // untouched apart from this file). So the honest statement is per KIND, and it is spelled as
+    // code rather than as a comment so that a caller cannot read the blanket answer above and
+    // conclude the knob covers its kind:
+    //
+    //   * for the two kinds this backend really keys on {slot, gen}, the knob defeats the
+    //     identity exactly as it always has (MagmaPipeClaimSlotMemos);
+    //   * for P4a's six there is nothing here to defeat, so the answer is FALSE - and
+    //     MG_IntegrationTest's HandleRecycleScenario reads that through its own build probe and
+    //     makes those cases' AbaControl arm assert the CORRECT pixels while SAYING that it is
+    //     not controlling anything for that kind. It does not assert a corruption that no code
+    //     on this tree can produce, which would be a permanently red always-on lane.
+    //
+    // WHAT MAKES IT TRUE LATER, in one sentence, so the next reader does not have to derive it:
+    // when a backend grows a Features.PipeHandleAbaControl consumer over its P4a object slot
+    // tables - one `if` in GetOrCreate / FindByHandle, the shape MagmaPipeClaimSlotMemos already
+    // has for vertex input - this function's per-kind answer becomes that consumer's, the
+    // integration probe finds the consumer, and the six cases flip to expecting the corruption.
     inline Bool MagmaPipeAbaControlDefeatsIdentity() {
         return MG_Config::Features.PipeHandleAbaControl;
     }
 
+    // WHICH KINDS THIS BACKEND ACTUALLY KEYS ON {slot, gen}, and therefore which kinds the knob
+    // above has an identity to defeat at all. `kind` is MG_Pipe::MGPipeKind.
+    //
+    // EXHAUSTIVE, WITH NO `default:`, for MG_IntegrationTest/Harness/PipeSlotPeek.cpp's reason:
+    // a kind added to MGPipeKind without a decision here must be a -Wswitch warning in this
+    // file rather than a row that silently inherits somebody else's answer. Being wrong in the
+    // "covered" direction is the expensive one - a control asserting a corruption nobody can
+    // produce is a permanently red always-on lane - so an undecided kind must never read true,
+    // and with no `default:` there is no arm for it to read true from.
+    //
+    // constexpr AND PINNED BY static_assert BELOW, which is what stops it rotting the way a
+    // predicate with no caller does: MagmaPipeIdentityTables mints exactly two kinds, the
+    // asserts say so in both directions, and the file no longer compiles if the tables and this
+    // statement of them ever part company. (Review F-m5: the earlier form had no caller at all
+    // and could not make anything red or green.)
+    inline constexpr Bool MagmaPipeAbaControlKindIsRekeyedHere(MG_Pipe::MGPipeKind kind) {
+        switch (kind) {
+            // The two MagmaPipeIdentityTables really mints.
+            case MG_Pipe::MGPipeKind::VertexElementsCso:
+            case MG_Pipe::MGPipeKind::Buffer:
+                return true;
+            // P4a's six object classes: still reached from their frontend objects on this
+            // backend (Magma's object paths are P7, ROADMAP.md:24), so there is no key here for
+            // the knob to defeat.
+            case MG_Pipe::MGPipeKind::Texture:
+            case MG_Pipe::MGPipeKind::Renderbuffer:
+            case MG_Pipe::MGPipeKind::Framebuffer:
+            case MG_Pipe::MGPipeKind::SamplerCso:
+            case MG_Pipe::MGPipeKind::SamplerViewCso:
+            case MG_Pipe::MGPipeKind::ShaderCso:
+            // ...and everything else this backend does not mint a handle for.
+            case MG_Pipe::MGPipeKind::None:
+            case MG_Pipe::MGPipeKind::Xfb:
+            case MG_Pipe::MGPipeKind::RenderStateCso:
+            case MG_Pipe::MGPipeKind::Fence:
+            case MG_Pipe::MGPipeKind::Query:
+            case MG_Pipe::MGPipeKind::Context:
+            case MG_Pipe::MGPipeKind::KindCount:
+                return false;
+        }
+        return false;
+    }
+
+    static_assert(MagmaPipeAbaControlKindIsRekeyedHere(MG_Pipe::MGPipeKind::VertexElementsCso),
+                  "MagmaPipeIdentityTables mints VertexElementsCso: the knob has an identity to "
+                  "defeat for it");
+    static_assert(MagmaPipeAbaControlKindIsRekeyedHere(MG_Pipe::MGPipeKind::Buffer),
+                  "MagmaPipeIdentityTables mints Buffer: the knob has an identity to defeat for it");
+    static_assert(!MagmaPipeAbaControlKindIsRekeyedHere(MG_Pipe::MGPipeKind::Texture) &&
+                      !MagmaPipeAbaControlKindIsRekeyedHere(MG_Pipe::MGPipeKind::Renderbuffer) &&
+                      !MagmaPipeAbaControlKindIsRekeyedHere(MG_Pipe::MGPipeKind::Framebuffer) &&
+                      !MagmaPipeAbaControlKindIsRekeyedHere(MG_Pipe::MGPipeKind::SamplerCso) &&
+                      !MagmaPipeAbaControlKindIsRekeyedHere(MG_Pipe::MGPipeKind::SamplerViewCso) &&
+                      !MagmaPipeAbaControlKindIsRekeyedHere(MG_Pipe::MGPipeKind::ShaderCso),
+                  "P4a's six object classes are not keyed on {slot, gen} on this backend, so "
+                  "HandleRecycleScenario's six AbaControl arms must NOT expect a corruption here. "
+                  "Wiring one of them is what flips this assert, this predicate and that arm - and "
+                  "MG_IntegrationTest's two-symbol probe over MG_Backend/DirectVulkan is what "
+                  "carries the answer into the lane");
+
+    // THERE IS DELIBERATELY NO PER-KIND WRAPPER HERE, and review F-v2-m3 is why. An earlier
+    // round carried `MagmaPipeAbaControlCoversKind(kind)` - the conjunction of the two
+    // statements above - and it had no caller anywhere in the tree: the knob's only two
+    // consumers (VulkanRenderer.cpp's VAO draw memo and VertexInputStateFactory.cpp's pipeline
+    // key) each hold ONE kind, VertexElementsCso, by construction, so the kind is not a
+    // variable at either site. A conjunction no build ever evaluates cannot be pinned the way
+    // the predicate above is pinned - it is not constexpr, because it reads MG_Config::Features,
+    // so no static_assert can reach it - which makes it exactly the rot F-m5 was raised about,
+    // one level up: an `&&` whose operands could be inverted or dropped with nothing to say so.
+    //
+    // The two pieces stand alone instead, and each is pinned by something that runs:
+    // MagmaPipeAbaControlKindIsRekeyedHere is constexpr and asserted in BOTH directions by the
+    // three static_asserts above, which compile in every Magma build; MagmaPipeAbaControlDefeats
+    // Identity is the knob, and its two consumers are what make it true or false. A call site
+    // that ever does hold a variable kind writes the `&&` there, where a build will run it.
+
     // The single consumer-table entry every VAO collapses onto while the control is on. Slot
     // 0 is a real, ordinary entry of both tables (MagmaPipeSlotIndex maps the first allocatable
     // handle onto it), so nothing about the tables changes shape for the control's sake.

MobileGL/MG_Backend/MGPipe/PipeInputs.h

@@ -688,7 +688,22 @@ namespace MobileGL::MG_Pipe {
 
     // The single global the backends read through MGB_CTX (ARCHITECTURE.md 9.2). An inline
     // variable: no .cpp is needed for the definition.
-    inline PipeInputs gPipeInputs{};
+    //
+    // LEAK-AT-EXIT STORAGE, and it is the same rule Init.cpp and GlobalObjects.cpp state for
+    // pGLContext and pActiveBackendObject: "a process that exits without eglTerminate simply
+    // leaks the global singletons to the OS instead of running destructors during static
+    // teardown". This block breaks that rule if it is a value, because its O-class members
+    // are SharedPtrs to FRONTEND objects: a VertexArrayObject that the application deleted
+    // while it was bound has its last reference here, and destroying this block from
+    // __run_exit_handlers therefore runs ~VertexArrayObject -> ~BufferObject at exit. Those
+    // destructors are not exit-safe and cannot be made so - they reach the client's slot
+    // allocator, the resource tracker, the vertex-input emitter, the applier AND, through
+    // MGPipeApplyResourceDestroy, the backend's own twin tables, deferred-release queue,
+    // buffer pool and driver entry points, every one of which is either already destroyed or
+    // about to be. So the reference is never dropped: nothing here can start such a chain.
+    // A live context releases these SharedPtrs the ordinary way, at the fill point.
+    // (P3a; the exit-time heap corruption this closes is p3a-results/exit-order-v1.md.)
+    inline PipeInputs& gPipeInputs = *new PipeInputs();
 
     // Every field has storage or is forwarded, and nothing else.
 #define MGP_INPUT_COUNT_ONE(Field, Member) +1

MobileGL/MG_Impl/GLImpl/Framebuffer/GL_Framebuffer.cpp

@@ -16,6 +16,14 @@
 #include <MG_Impl/GLImpl/Getter/GL_Getter.h>
 #include <MG_State/GLState/ErrorState/Error.h>
 #include <MG_Impl/Pipe/PipeFill.h>
+#if MOBILEGL_PIPE_PUSH
+// P4a, ID-19(c). This file is the ONLY place every DSA framebuffer entry point lives, and the
+// emitter it reaches is this package's own header rather than a declaration in one of the
+// contract's: MG_Pipe/PipeMutation.h is the door MG_State has into the client and carries no
+// framebuffer row, and MG_Impl/GLImpl and MG_Impl/Pipe are the same layer (this file already
+// includes MG_Impl/Pipe/PipeFill.h for MGP_FILL).
+#include <MG_Impl/Pipe/FramebufferEmit.h>
+#endif
 #include <MG_Util/Converters/GLToStr/GLEnumConverter.h>
 #include <MG_Util/Converters/GLToMG/TextureEnumConverter.h>
 #include <MG_Util/Converters/MGToMG/TextureEnumConverter.h>
@@ -613,6 +621,35 @@ namespace MobileGL::MG_Impl::GLImpl {
 
             framebufferObject->AttachTexture(attachmentType, textureObject, textureUploadTarget, level, 0, layered);
         }
+#if MOBILEGL_PIPE_PUSH
+        // P4a, ID-19(c): ANY FRAMEBUFFER THE SERVER IS ABOUT TO RECEIVE BY NAME HAS A RECORD.
+        //
+        // The applier keeps framebuffer records PER OBJECT, keyed by the handle - but before
+        // ID-19 it held only the two BOUND-target records, and the emitter only ever built them
+        // at the validate point out of the two bindings. So glClearNamedFramebufferfv(fbo) or
+        // glBlitNamedFramebuffer(..., fbo, ...) on an fbo bound to NEITHER binding reached a
+        // backend that minted a fresh driver framebuffer with no attachments, found no record
+        // for it, declined, and issued the clear against it anyway: GL_INVALID_FRAMEBUFFER_-
+        // OPERATION and nothing cleared, where the legacy arm cleared correctly.
+        //
+        // TWO CLASSES OF SITE call this, and both are "the point at which the object is final
+        // for this call": the five CONSUMERS (blit and the four clears) publish immediately
+        // before MGP_FILL, so the record precedes the verb that hands the object over and a
+        // later bound-target record for the same object still wins; the ten MUTATORS (the DSA
+        // attachment, draw-buffer and read-buffer setters) publish immediately after the
+        // frontend mutation, because they have no validate point at all - FillPoints.def has no
+        // verb for any of them, so there is no MGP_FILL to sit in front of.
+        //
+        // A CALL THAT MOVED NOTHING IS FREE: the record's ContentHash is the emitter's own
+        // suppressor and it is keyed per framebuffer object, so a redundant publish emits zero
+        // bytes. EmitFramebufferByName picks Draw/Read/Both over Named when the object IS
+        // bound, so a Named record can never overwrite a bound record's Target underneath the
+        // binding that resolves through it.
+        void PipePublishFramebufferByName(const SharedPtr<MG_State::GLState::FramebufferObject>& fbo) {
+            if (!fbo) return;
+            MG_Pipe::MGPipeFramebufferEmitterInstance().EmitFramebufferByName(*fbo);
+        }
+#endif
     } // namespace
 
     void BlitFramebuffer_Backend(GLint srcX0, GLint srcY0, GLint srcX1, GLint srcY1, GLint dstX0, GLint dstY0,
@@ -631,6 +668,10 @@ namespace MobileGL::MG_Impl::GLImpl {
             MGLOG_E_ONCE("glBlitNamedFramebuffer skipped: backend does not implement explicit framebuffer blit.");
             return;
         }
+#if MOBILEGL_PIPE_PUSH
+        PipePublishFramebufferByName(readFramebuffer);
+        PipePublishFramebufferByName(drawFramebuffer);
+#endif
         MGP_FILL(BlitNamedFramebuffer);
         blitNamedFramebuffer(readFramebuffer, drawFramebuffer, srcX0, srcY0, srcX1, srcY1, dstX0, dstY0, dstX1,
                              dstY1, mask, filter);
@@ -643,6 +684,9 @@ namespace MobileGL::MG_Impl::GLImpl {
             MGLOG_E_ONCE("glClearNamedFramebufferfv skipped: backend does not implement explicit framebuffer clear.");
             return;
         }
+#if MOBILEGL_PIPE_PUSH
+        PipePublishFramebufferByName(framebuffer);
+#endif
         MGP_FILL(ClearNamedFramebufferfv);
         clearNamedFramebufferfv(framebuffer, buffer, drawbuffer, value);
     }
@@ -654,6 +698,9 @@ namespace MobileGL::MG_Impl::GLImpl {
             MGLOG_E_ONCE("glClearNamedFramebufferfi skipped: backend does not implement explicit framebuffer clear.");
             return;
         }
+#if MOBILEGL_PIPE_PUSH
+        PipePublishFramebufferByName(framebuffer);
+#endif
         MGP_FILL(ClearNamedFramebufferfi);
         clearNamedFramebufferfi(framebuffer, buffer, drawbuffer, depth, stencil);
     }
@@ -665,6 +712,9 @@ namespace MobileGL::MG_Impl::GLImpl {
             MGLOG_E_ONCE("glClearNamedFramebufferiv skipped: backend does not implement explicit framebuffer clear.");
             return;
         }
+#if MOBILEGL_PIPE_PUSH
+        PipePublishFramebufferByName(framebuffer);
+#endif
         MGP_FILL(ClearNamedFramebufferiv);
         clearNamedFramebufferiv(framebuffer, buffer, drawbuffer, value);
     }
@@ -676,6 +726,9 @@ namespace MobileGL::MG_Impl::GLImpl {
             MGLOG_E_ONCE("glClearNamedFramebufferuiv skipped: backend does not implement explicit framebuffer clear.");
             return;
         }
+#if MOBILEGL_PIPE_PUSH
+        PipePublishFramebufferByName(framebuffer);
+#endif
         MGP_FILL(ClearNamedFramebufferuiv);
         clearNamedFramebufferuiv(framebuffer, buffer, drawbuffer, value);
     }
@@ -1404,6 +1457,9 @@ namespace MobileGL::MG_Impl::GLImpl {
 
         if (texture == 0) {
             framebufferObject->Detach(attachmentType);
+#if MOBILEGL_PIPE_PUSH
+        PipePublishFramebufferByName(framebufferObject);
+#endif
             return;
         }
 
@@ -1430,6 +1486,9 @@ namespace MobileGL::MG_Impl::GLImpl {
         }
 
         framebufferObject->AttachTexture(attachmentType, textureObject, textureUploadTarget, level, 0, layered);
+#if MOBILEGL_PIPE_PUSH
+        PipePublishFramebufferByName(framebufferObject);
+#endif
     }
 
     void NamedFramebufferTextureWithUploadTarget_State(const char* functionName, GLuint framebuffer, GLenum attachment,
@@ -1453,6 +1512,9 @@ namespace MobileGL::MG_Impl::GLImpl {
 
         if (texture == 0) {
             framebufferObject->Detach(attachmentType);
+#if MOBILEGL_PIPE_PUSH
+        PipePublishFramebufferByName(framebufferObject);
+#endif
             return;
         }
 
@@ -1480,6 +1542,9 @@ namespace MobileGL::MG_Impl::GLImpl {
         }
 
         framebufferObject->AttachTexture(attachmentType, textureObject, textureUploadTarget, level);
+#if MOBILEGL_PIPE_PUSH
+        PipePublishFramebufferByName(framebufferObject);
+#endif
     }
 
     void NamedFramebufferTexture1D_State(GLuint framebuffer, GLenum attachment, GLenum textarget, GLuint texture,
@@ -1534,6 +1599,9 @@ namespace MobileGL::MG_Impl::GLImpl {
 
         if (texture == 0) {
             framebufferObject->Detach(attachmentType);
+#if MOBILEGL_PIPE_PUSH
+        PipePublishFramebufferByName(framebufferObject);
+#endif
             return;
         }
 
@@ -1636,6 +1704,9 @@ namespace MobileGL::MG_Impl::GLImpl {
 
         framebufferObject->AttachTexture(attachmentType, textureObject, textureUploadTarget, level, layer,
                                          /*layered=*/false);
+#if MOBILEGL_PIPE_PUSH
+        PipePublishFramebufferByName(framebufferObject);
+#endif
     }
 
     void FramebufferRenderbuffer_State(GLenum target, GLenum attachment, GLenum renderbuffertarget,
@@ -1705,6 +1776,9 @@ namespace MobileGL::MG_Impl::GLImpl {
 
         if (renderbuffer == 0) {
             framebufferObject->Detach(attachmentType);
+#if MOBILEGL_PIPE_PUSH
+        PipePublishFramebufferByName(framebufferObject);
+#endif
             return;
         }
 
@@ -1714,6 +1788,9 @@ namespace MobileGL::MG_Impl::GLImpl {
         if (!renderbufferObject) return;
 
         framebufferObject->AttachRenderbuffer(attachmentType, renderbufferObject);
+#if MOBILEGL_PIPE_PUSH
+        PipePublishFramebufferByName(framebufferObject);
+#endif
     }
 
     void DrawBuffersForFramebuffer_State(const SharedPtr<MG_State::GLState::FramebufferObject>& fbo, Bool isDefaultFBO,
@@ -1913,6 +1990,9 @@ namespace MobileGL::MG_Impl::GLImpl {
             : GetNamedFramebufferObject_State(framebuffer, "NamedFramebufferDrawBuffers_State");
         if (!framebufferObject) return;
         DrawBuffersForFramebuffer_State(framebufferObject, framebuffer == 0, n, bufs, false);
+#if MOBILEGL_PIPE_PUSH
+        PipePublishFramebufferByName(framebufferObject);
+#endif
     }
 
     void NamedFramebufferDrawBuffer_State(GLuint framebuffer, GLenum buf) {
@@ -1927,6 +2007,9 @@ namespace MobileGL::MG_Impl::GLImpl {
             const GLenum bufs[] = {buf};
             DrawBuffersForFramebuffer_State(framebufferObject, framebuffer == 0, 1, bufs, true);
         }
+#if MOBILEGL_PIPE_PUSH
+        PipePublishFramebufferByName(framebufferObject);
+#endif
     }
 
     void NamedFramebufferReadBuffer_State(GLuint framebuffer, GLenum src) {
@@ -1936,6 +2019,9 @@ namespace MobileGL::MG_Impl::GLImpl {
         if (!framebufferObject) return;
         ReadBufferForFramebuffer_State(framebufferObject, framebuffer == 0, src,
                                        "NamedFramebufferReadBuffer_State");
+#if MOBILEGL_PIPE_PUSH
+        PipePublishFramebufferByName(framebufferObject);
+#endif
     }
 
     SharedPtr<MG_State::GLState::FramebufferObject> GetFramebufferObjectForNamedClear(GLuint framebuffer,

MobileGL/MG_Impl/GLImpl/Texture/GL_Texture.cpp

@@ -31,6 +31,9 @@
 #include <MG_Util/Math/FixedPointConversion.h>
 #include <MG_State/GLState/TextureState/TextureObjectBuffer.h>
 #include <MG_Impl/Pipe/PipeFill.h>
+// P4a, ID-18 M2. The ONE door MG_State and MG_Impl have into the client's emitters; the three
+// call sites below are declarations only, exactly as the frontend's mutators are.
+#include <MG_Pipe/PipeMutation.h>
 
 namespace MobileGL::MG_Impl::GLImpl {
     static SharedPtr<MG_State::GLState::ITextureObject> nullTextureObject;
@@ -1337,6 +1340,30 @@ namespace MobileGL::MG_Impl::GLImpl {
                     std::format("pname {} is not a valid texture parameter.", MG_Util::ConvertGLEnumToString(pname))));
             return;
         }
+#if MOBILEGL_PIPE_PUSH
+        // P4a, ID-18 M2 - THE THIRTEENTH MGP_NOTE_AGGREGATE(TextureParams) SITE, and the one
+        // no publisher reached. Nine of the thirteen are TextureObject.cpp's own mutators and
+        // publish through TextureObjectBase::PipePublishParams; the tenth is
+        // SetDepthStencilTextureMode; two more move fields MGPTextureParams does not carry. The
+        // last is SamplerObject::BumpVersion, whose own comment calls it "the one choke point
+        // every setter reaches" - and MGPTextureParams takes MinLod, MaxLod and LodBias off that
+        // object, so every glTexParameter that writes GL_TEXTURE_MIN_LOD / MAX_LOD / LOD_BIAS
+        // landed on state nothing watched and the applier's record kept saying MinLod = 0.
+        // Wrong pixels, not a lost optimisation.
+        //
+        // THE HOOK IS HERE RATHER THAN ON BumpVersion because MG_State/GLState/SamplerState is
+        // package C's after the tag; C.7 grants this file for exactly this class of path ("the
+        // grant is one call site per path"), and this switch IS the path - every arm of it
+        // either writes the built-in SamplerObject or writes a texture field that publishes for
+        // itself. Placed after the switch, so the error arms above return without emitting.
+        //
+        // IT IS ALSO ID-14's RE-EMIT HOOK. C's sampler CSO cache is content-addressed, so the
+        // handle MGPTextureParams::BuiltinSampler names MOVES WITH THE CONTENT; the emitter
+        // re-Acquires from the cache and releases the previous handle here. An over-call is
+        // free: the emitter's version-first skip reads GetTextureParamsVersion() AND
+        // SamplerObject::GetVersion() and returns without hashing anything when neither moved.
+        MobileGL::MG_Pipe::MGPipeEmitTextureParams(*textureObject);
+#endif
     }
 
     void TextureParameterObjectf_State(const SharedPtr<MG_State::GLState::ITextureObject>& textureObject, GLenum pname,
@@ -1415,6 +1442,30 @@ namespace MobileGL::MG_Impl::GLImpl {
                     std::format("pname {} is not a valid texture parameter.", MG_Util::ConvertGLEnumToString(pname))));
             return;
         }
+#if MOBILEGL_PIPE_PUSH
+        // P4a, ID-18 M2 - THE THIRTEENTH MGP_NOTE_AGGREGATE(TextureParams) SITE, and the one
+        // no publisher reached. Nine of the thirteen are TextureObject.cpp's own mutators and
+        // publish through TextureObjectBase::PipePublishParams; the tenth is
+        // SetDepthStencilTextureMode; two more move fields MGPTextureParams does not carry. The
+        // last is SamplerObject::BumpVersion, whose own comment calls it "the one choke point
+        // every setter reaches" - and MGPTextureParams takes MinLod, MaxLod and LodBias off that
+        // object, so every glTexParameter that writes GL_TEXTURE_MIN_LOD / MAX_LOD / LOD_BIAS
+        // landed on state nothing watched and the applier's record kept saying MinLod = 0.
+        // Wrong pixels, not a lost optimisation.
+        //
+        // THE HOOK IS HERE RATHER THAN ON BumpVersion because MG_State/GLState/SamplerState is
+        // package C's after the tag; C.7 grants this file for exactly this class of path ("the
+        // grant is one call site per path"), and this switch IS the path - every arm of it
+        // either writes the built-in SamplerObject or writes a texture field that publishes for
+        // itself. Placed after the switch, so the error arms above return without emitting.
+        //
+        // IT IS ALSO ID-14's RE-EMIT HOOK. C's sampler CSO cache is content-addressed, so the
+        // handle MGPTextureParams::BuiltinSampler names MOVES WITH THE CONTENT; the emitter
+        // re-Acquires from the cache and releases the previous handle here. An over-call is
+        // free: the emitter's version-first skip reads GetTextureParamsVersion() AND
+        // SamplerObject::GetVersion() and returns without hashing anything when neither moved.
+        MobileGL::MG_Pipe::MGPipeEmitTextureParams(*textureObject);
+#endif
     }
 
     void GetTextureParameterObjectiv_State(const SharedPtr<MG_State::GLState::ITextureObject>& textureObject,
@@ -2105,6 +2156,30 @@ namespace MobileGL::MG_Impl::GLImpl {
                     std::format("pname {} is not a valid texture parameter.", MG_Util::ConvertGLEnumToString(pname))));
             return;
         }
+#if MOBILEGL_PIPE_PUSH
+        // P4a, ID-18 M2 - THE THIRTEENTH MGP_NOTE_AGGREGATE(TextureParams) SITE, and the one
+        // no publisher reached. Nine of the thirteen are TextureObject.cpp's own mutators and
+        // publish through TextureObjectBase::PipePublishParams; the tenth is
+        // SetDepthStencilTextureMode; two more move fields MGPTextureParams does not carry. The
+        // last is SamplerObject::BumpVersion, whose own comment calls it "the one choke point
+        // every setter reaches" - and MGPTextureParams takes MinLod, MaxLod and LodBias off that
+        // object, so every glTexParameter that writes GL_TEXTURE_MIN_LOD / MAX_LOD / LOD_BIAS
+        // landed on state nothing watched and the applier's record kept saying MinLod = 0.
+        // Wrong pixels, not a lost optimisation.
+        //
+        // THE HOOK IS HERE RATHER THAN ON BumpVersion because MG_State/GLState/SamplerState is
+        // package C's after the tag; C.7 grants this file for exactly this class of path ("the
+        // grant is one call site per path"), and this switch IS the path - every arm of it
+        // either writes the built-in SamplerObject or writes a texture field that publishes for
+        // itself. Placed after the switch, so the error arms above return without emitting.
+        //
+        // IT IS ALSO ID-14's RE-EMIT HOOK. C's sampler CSO cache is content-addressed, so the
+        // handle MGPTextureParams::BuiltinSampler names MOVES WITH THE CONTENT; the emitter
+        // re-Acquires from the cache and releases the previous handle here. An over-call is
+        // free: the emitter's version-first skip reads GetTextureParamsVersion() AND
+        // SamplerObject::GetVersion() and returns without hashing anything when neither moved.
+        MobileGL::MG_Pipe::MGPipeEmitTextureParams(*textureObject);
+#endif
     }
 
     void TexParameteri_State(GLenum target, GLenum pname, GLint param) {

MobileGL/MG_Impl/Pipe/CompositeResolver.h

@@ -0,0 +1,270 @@
+// MobileGL - MobileGL/MG_Impl/Pipe/CompositeResolver.h
+// Copyright (c) 2025-2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+
+#pragma once
+#include <Includes.h>
+
+// P4a's PROGRAM-PIPELINE COMPOSITE, on the client side.
+//
+// GLContext::GetProgramForDraw() already flattens a bound pipeline into one hidden composite
+// ProgramObject entirely in the frontend - it joins every graphics stage, computes the
+// pipeline's draw-program signature, looks it up in the pipeline's own cache and, on a miss,
+// attaches each stage's LINKED SNAPSHOT into a fresh ProgramObject and links it. All of that
+// is frontend work and none of it moves. What this file adds is the one thing the wire needs:
+// the composite gets ONE handle, out of the ShaderCso reserved high band, and
+// create_shader_state goes out for it exactly as for an ordinary program. THE SERVER NEVER
+// LEARNS IT IS A COMPOSITE and needs no "resolved draw program" hook at all.
+//
+// WHY A BAND RATHER THAN A FLAG ON THE HANDLE: a flag would have to be carried, honoured and
+// masked off by every consumer of a ShaderCso handle, on both sides; a reserved slot range is
+// a property of the allocator instead, so "an ordinary program can never be handed a composite
+// slot" is true by construction. MGPipeSlotAllocator::Allocate refuses the band outright and
+// AllocateComposite is the only door in.
+//
+// WHAT THIS FILE IS ACTUALLY FOR: the composite's slot has TWO INDEPENDENT RELEASE PATHS and
+// either order has to free it exactly once.
+//   * the pipeline cache drops the composite when the draw-program signature moves. In the
+//     frontend that overwrite drops the last SharedPtr, so the composite's own destructor
+//     usually runs first; the resolver still speaks the release, because "usually" is not a
+//     contract and a client that only reacted to destructors would leak a slot the moment the
+//     frontend started holding a second reference.
+//   * the composite ProgramObject's own ~ProgramObject, which is an ordinary program's death
+//     path and takes the same helper.
+// Both go through MGPipeEmitShaderCsoDestroyAndFree, and whichever runs second is a PROVEN
+// no-op: MGPipeSlotAllocator::Free refuses a slot that is not live at that generation and
+// bumps no generation of its own, so a double release cannot skip a generation either.
+//
+// THE MEMO's KEY IS (CONTEXT ID, PIPELINE GL NAME) AND THE CONTEXT HALF IS NOT OPTIONAL.
+// This resolver is a PROCESS singleton while a pipeline's GL name is per context: GLContext
+// owns m_programPipelines AND its own name generator m_programPipelineNames (Core.h), so name
+// N names two different ProgramPipelineObjects in two contexts, each with its own composite
+// and its own handle. Keyed on the name alone, the first emission after a make-current found
+// the OTHER context's entry, matched nothing - two composites are two ProgramObjects with two
+// lifetime ids, so the handles differ even when the stage set and the signature are identical
+// - and released it: a delete_shader_state and a cleared publication latch for a composite
+// whose frontend ProgramObject is alive, its band slot handed back and re-issued at gen + 1,
+// and the server rebuilding that program (glslang + SPIR-V + spirv-opt, the very cost the
+// signature below exists to avoid) once per context switch.
+//
+// THE CONTEXT ID IS GLContext::GetTextureContextId() AND NOTHING ELSE - the tree's existing
+// never-reused per-context id (TextureState::AllocateContextId; PipeInputs carries it as
+// m_textureContextId at seven fill points and the backends' own per-context memos key on it).
+// Deliberately NOT the GLContext ADDRESS that MGB_CTX_IDENTITY and MGPipeTracker::m_context
+// compare, because Core.h states the reason that id exists at all: a context freed and remade
+// lands on the old heap address, which would put this same defect back one context recreation
+// later.
+//
+// WHAT RELEASES A DESTROYED CONTEXT's ENTRIES: nothing in this file, and that is the correct
+// answer rather than an omission. Destroying a context drops m_programPipelines, which drops
+// each ProgramPipelineObject, which drops the composite it cached; ~ProgramObject then runs
+// MGPipeEmitShaderCsoDestroyAndFree - the composite's OWN release path, the second of the two
+// above - and the slot goes back exactly once. The entries those composites leave behind can
+// never be found again (no future Observe can carry a dead context id) and could not release
+// anything if they were (the allocator erases the lifetime-id mapping on Free), so Reset()
+// DROPS them instead of releasing them. That is also what bounds the vector; see Reset().
+//
+// THE SIGNATURE IS ComputeDrawProgramSignature(), the per-graphics-stage {lifetimeId,
+// GetLinkVersion()} array - and DELIBERATELY NOT GetBackendStateVersion(), which is what made
+// the SSO conformance loop rebuild the composite (glslang + SPIR-V + spirv-opt) on every draw,
+// because a glUniform1i to a sampler moves it.
+//
+// HEADER-ONLY, for the ownership reason Tracker.h states: a new .cpp would need the root
+// CMakeLists.txt, which is the contract package's.
+//
+// IT IS INCLUDED BY ProgramEmit.h AND NOT THE OTHER WAY ROUND, deliberately: the composite is
+// a special case of the program family's own emission, so the family header depends on this
+// one and this one depends on nothing of the family's. The reverse arrangement would make the
+// resolver reachable only from a translation unit that had already decided to use it, i.e.
+// dead in the build that matters and live only in the tests.
+#if MOBILEGL_PIPE_PUSH
+#include <MG_Impl/Pipe/SlotAllocator.h>
+#include <MG_Pipe/MGPipe.h>
+#include <MG_Pipe/PipeMutation.h>
+#include <MG_State/GLState/ProgramState/ProgramObject.h>
+#include <MG_State/GLState/ProgramState/ProgramPipelineObject.h>
+
+namespace MobileGL::MG_Pipe {
+
+    // IS THIS PROGRAM A PIPELINE COMPOSITE? A composite is the one ProgramObject in the system
+    // constructed with external index 0 (Core.cpp's MakeShared<ProgramObject>(0u)), and that is
+    // not an accident of implementation: it is deliberately not a named program, so it must not
+    // answer glIsProgram and must not consume a GL name, and glCreateProgram never returns 0.
+    //
+    // ASKED THIS WAY RATHER THAN CARRIED ON THE OBJECT because a Bool member on ProgramObject
+    // would resize the pull build's object and break G1 outright - the phase's admitted-resize
+    // set is empty - and a hook in Core.cpp would have to be maintained on a path that already
+    // states the invariant in its own comment.
+    inline Bool MGPipeProgramIsPipelineComposite(const MG_State::GLState::ProgramObject& program) {
+        return program.GetExternalIndex() == 0;
+    }
+
+    class MGPipeCompositeResolver {
+    public:
+        using ProgramObject = MG_State::GLState::ProgramObject;
+        using ProgramPipelineObject = MG_State::GLState::ProgramPipelineObject;
+        using DrawProgramSignature = ProgramPipelineObject::DrawProgramSignature;
+
+        struct Counters {
+            Uint64 Mints = 0;    // signatures this resolver has seen minted
+            Uint64 Reuses = 0;   // a signature that had not moved
+            Uint64 Releases = 0; // signature-move releases, i.e. the pipeline-cache path
+            // Entries dropped by Reset() because the composite's slot was already gone - the
+            // shape every entry of a DESTROYED CONTEXT ends in. A dropped entry is not a
+            // release: nothing is emitted and nothing is freed, the obligation having been
+            // discharged by the composite's own ~ProgramObject.
+            Uint64 Sweeps = 0;
+        };
+
+        // Told, at every emission, which composite the frontend handed out for which pipeline.
+        // Returns the handle the emitter should use, which is always the one already minted off
+        // the composite's own lifetime id - the resolver never mints a second identity for an
+        // object that has one.
+        //
+        // WHEN THE SIGNATURE MOVES the previous composite's slot is released here, through the
+        // one death helper and in its fixed order. That is the pipeline-cache release path; the
+        // composite's own destructor is the other one and the second of the two is the proven
+        // no-op.
+        MGPipeHandle Observe(Uint64 contextId, const ProgramPipelineObject& pipeline,
+                             const ProgramObject& composite, MGPipeHandle handle) {
+            const DrawProgramSignature signature = pipeline.ComputeDrawProgramSignature();
+            const Uint pipelineName = pipeline.GetExternalIndex();
+            Entry* entry = Find(contextId, pipelineName);
+            if (entry != nullptr) {
+                if (entry->Signature == signature && entry->Handle == handle) {
+                    // THE SAME COMPOSITE. Not merely "the same signature": the handle is minted
+                    // off the composite ProgramObject's own lifetime id, so an identical handle
+                    // IS an identical object and there is nothing to release. Live is
+                    // deliberately NOT touched - it is the release obligation and it is still
+                    // owed for exactly this handle.
+                    ++m_counters.Reuses;
+                    return handle;
+                }
+                // A MOVED SIGNATURE ON THIS CONTEXT's OWN ENTRY, which is the only thing that
+                // can reach here now: another context's pipeline of the same name is not found
+                // above and therefore not released, its obligation staying owed to the context
+                // that took it.
+                ReleaseEntry(*entry);
+            } else {
+                m_entries.push_back(Entry{});
+                entry = &m_entries.back();
+                entry->ContextId = contextId;
+                entry->PipelineName = pipelineName;
+            }
+            entry->Signature = signature;
+            entry->Handle = handle;
+            entry->CompositeLifetimeId = composite.GetLifetimeId();
+            entry->Live = true;
+            ++m_counters.Mints;
+            return handle;
+        }
+
+        // A make-current, and it RELEASES NOTHING. The entries name composites that belong to
+        // the frontend objects of the context being left, those objects outlive the switch, and
+        // releasing them would emit a delete for a live program.
+        //
+        // NOR IS ANY MEMO INVALIDATED, and that is what the context key bought. This used to
+        // clear a per-entry `Fresh` flag beside `Live`, because with a name-only key an entry
+        // could not say whether it described "my own pipeline before the switch" or "another
+        // context's pipeline of the same name" - and exactly one of those two properties could
+        // hold at a time. The key answers the question directly now, so the freshness flag and
+        // its one reader (a HandleFor() accessor that had no caller anywhere in the tree) are
+        // both gone rather than left as scaffolding: `Live`, the release obligation, is the
+        // entry's only state and nothing but ReleaseEntry may clear it.
+        //
+        // WHAT IS LEFT TO DO HERE IS RECLAMATION, and this is the one moment the client is told
+        // that a context boundary was crossed. An entry whose composite slot is no longer live
+        // has had its obligation discharged elsewhere - by that composite's own ~ProgramObject,
+        // which is precisely what happened to EVERY entry of a context that has just been
+        // destroyed - so it is DROPPED rather than released: a release would resolve nothing
+        // anyway (the allocator erases the lifetime-id mapping on Free) and no reader is left.
+        // Without this the vector would grow by one per (context, pipeline name) pair the
+        // process ever used, where the name-only key bounded it by the highest pipeline name;
+        // with it, it is bounded by the pairs whose composite slot is actually live.
+        void Reset() {
+            SizeT kept = 0;
+            for (SizeT i = 0; i < m_entries.size(); ++i) {
+                if (!m_entries[i].Live || !MGPipeSlots().IsLive(MGPipeKind::ShaderCso, m_entries[i].Handle)) {
+                    ++m_counters.Sweeps;
+                    continue;
+                }
+                if (kept != i) m_entries[kept] = m_entries[i];
+                ++kept;
+            }
+            m_entries.resize(kept);
+        }
+
+        void ResetCounters() { m_counters = Counters{}; }
+
+        // Diagnostics and unit cases only; nothing on the emission path asks. There is no
+        // HandleFor(name) accessor and there must not be one: the emitter takes the handle from
+        // the composite ProgramObject it already holds, so a lookup by name would be a second
+        // authority on an identity the allocator already owns.
+        SizeT Size() const { return m_entries.size(); }
+        const Counters& GetCounters() const { return m_counters; }
+
+    private:
+        struct Entry {
+            // NO FRONTEND SharedPtr, and that is the exit-order rule rather than a style
+            // choice: a static that held one would put a frontend destructor on an exit
+            // handler's path into a torn-down pipe. A GL name, a signature of plain integers,
+            // a handle and a lifetime id are all this needs.
+            // KEYED ON (CONTEXT ID, GL NAME), and the name half is the GL name because a
+            // ProgramPipelineObject has no lifetime id - ComputeDrawProgramSignature reads the
+            // STAGE programs' ids and the pipeline itself carries none. The context half is
+            // GLContext::GetTextureContextId(); see the file header for why the name alone was
+            // wrong and why the context ADDRESS would be too.
+            //
+            // WITHIN ONE CONTEXT glGenProgramPipelines recycles names, so a deleted-and-
+            // recreated pipeline can still inherit its predecessor's entry; that is bounded and
+            // self-correcting rather than a hazard. The first Observe on the new object finds a
+            // signature and a handle that do not match and releases the old entry, and that
+            // release resolves NOTHING - the allocator erases the lifetime-id mapping on Free,
+            // so a stale CompositeLifetimeId emits no delete and frees no slot; all it costs is
+            // one redundant, idempotent death notice, which is the same shape the composite's
+            // own second release path already has.
+            Uint64 ContextId = 0;
+            Uint PipelineName = 0;
+            DrawProgramSignature Signature{};
+            MGPipeHandle Handle = kMGPipeNullHandle;
+            Uint64 CompositeLifetimeId = 0;
+            // THE RELEASE OBLIGATION. Set when this entry takes responsibility for a composite's
+            // slot, cleared ONLY by ReleaseEntry when that responsibility is discharged.
+            Bool Live = false;
+        };
+
+        // BOTH HALVES OF THE KEY, always. An entry of another context is not this pipeline's
+        // entry: not found, not matched, not released.
+        Entry* Find(Uint64 contextId, Uint pipelineName) {
+            for (Entry& entry : m_entries) {
+                if (entry.ContextId == contextId && entry.PipelineName == pipelineName) return &entry;
+            }
+            return nullptr;
+        }
+
+        void ReleaseEntry(Entry& entry) {
+            if (!entry.Live || entry.CompositeLifetimeId == 0) return;
+            entry.Live = false;
+            MGPipeEmitShaderCsoDestroyAndFree(entry.CompositeLifetimeId);
+            entry.Handle = kMGPipeNullHandle;
+            entry.CompositeLifetimeId = 0;
+            ++m_counters.Releases;
+        }
+
+        Vector<Entry> m_entries;
+        Counters m_counters;
+    };
+
+    inline MGPipeCompositeResolver& MGPipeCompositeResolverInstance() {
+        // NEVER DESTROYED, for MGPipeTrackerInstance()' reason, and named in the phase's risk
+        // list beside the other three new client singletons: heap-constructed and intentionally
+        // leaked at exit, holding no frontend SharedPtr.
+        static MGPipeCompositeResolver* resolver = new MGPipeCompositeResolver();
+        return *resolver;
+    }
+} // namespace MobileGL::MG_Pipe
+#endif // MOBILEGL_PIPE_PUSH

MobileGL/MG_Impl/Pipe/CsoCache.h

@@ -195,8 +195,11 @@ namespace MobileGL::MG_Pipe {
     // when the pipeline version moved, and it keeps the eviction order in the same array as
     // the content - a map would need a second structure to answer "which is oldest".
     inline MGPipeCsoCache& MGPipeCsoCacheInstance() {
-        static MGPipeCsoCache cache;
-        return cache;
+        // NEVER DESTROYED, for MGPipeTrackerInstance()' reason (MG_Impl/Pipe/Tracker.h): the
+        // rule covers every MGPipe process singleton, not only the ones on today's death
+        // paths.
+        static MGPipeCsoCache* cache = new MGPipeCsoCache();
+        return *cache;
     }
 } // namespace MobileGL::MG_Pipe
 #endif // MOBILEGL_PIPE_PUSH

MobileGL/MG_Impl/Pipe/FramebufferEmit.h

@@ -0,0 +1,659 @@
+// MobileGL - MobileGL/MG_Impl/Pipe/FramebufferEmit.h
+// Copyright (c) 2025-2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+
+#pragma once
+#include <Includes.h>
+
+// The CLIENT side of P4a's framebuffer family: set_framebuffer_state, emitted at the validate
+// point once per bound TARGET that moved, or once with Target = Both when the two bindings
+// name the same object.
+//
+// THIS FILE IS CREATED BY THE CONTRACT COMMIT AND FILLED BY THE PACKAGE THAT OWNS IT, and the
+// split is the whole reason it exists this early. MG_Impl/Pipe/PipeFill.cpp is the contract
+// package's for the entire phase - it carries Coverage.def's enum-coupled block, the validate
+// point and the death helpers - so the emitter package must not edit it. What it edits instead
+// is this header: the emitter's BODY, and the value of kMGPipeWiredFramebufferSubsystem below.
+// That is what makes "no file is touched twice by two packages" structural rather than a
+// convention, and it is what the bb2a236d semantic-merge trap taught (two branches green
+// separately, the integrated tree not compiling).
+//
+// HEADER-ONLY, for the ownership reason Tracker.h and ResourceTracker.h both state: the root
+// CMakeLists.txt that would name a new .cpp is the contract package's and is frozen behind the
+// tag. MG_Impl/Pipe/PipeFill.cpp is the one translation unit that includes it in the library.
+#if MOBILEGL_PIPE_PUSH
+#include <MG_Impl/Pipe/SetHashSuppressor.h>
+#include <MG_Impl/Pipe/SlotAllocator.h>
+#include <MG_Impl/Pipe/TextureEmit.h>
+#include <MG_Impl/Pipe/Tracker.h>
+#include <MG_Pipe/MGPipe.h>
+#include <MG_Pipe/PipeApply.h>
+#include <MG_State/GLState/Core.h>
+#include <MG_Util/Metrics/PipeStats.h>
+
+#include <xxhash.h>
+
+#include <algorithm>
+
+namespace MobileGL::MG_Pipe {
+
+    // WHICH SUBSYSTEM BIT THIS BUILD ACTUALLY EMITS FOR. PipeFill.cpp ORs the four per-family
+    // constants into kMGPipeWiredSubsystems, so the bit is added by the commit that gives the
+    // emitters their bodies, with no file touched twice - and a Coverage.def row can never
+    // silently drop a field on the floor before the call that carries it exists.
+    //
+    // TURNING IT ON RETIRES NO PULL. GetFramebufferBindingSlot is the family's one
+    // Coverage.def emitted row and PipeFill.cpp's EmittedCallSuppliesTheWholeField answers
+    // FALSE for it, with the reason: the field's storage is a BindingSlot<FramebufferObject> -
+    // a frontend heap reference - and the call that supplies it carries eight-byte {slot, gen}
+    // handles and a fully resolved descriptor. So this bit switches the EMISSION on and the
+    // residual fill keeps writing the mirror, which is what keeps the verify lane at zero
+    // divergence.
+    inline constexpr Uint64 kMGPipeWiredFramebufferSubsystem = kMGPipeSubsystemFramebuffer;
+
+    inline Bool MGPipeFramebufferSubsystemEnabled() {
+        return (kMGPipeWiredFramebufferSubsystem & kMGPipeSubsystemFramebuffer) != 0 &&
+               (MG_Config::Features.PipePush & kMGPipeSubsystemFramebuffer) != 0;
+    }
+
+    // ---------------------------------------------------------------------------------
+    // D-C1: the MGPSurface builder, one pure function, one statement per field
+    // ---------------------------------------------------------------------------------
+
+    // MGPSurface::Kind's three constants ARE THE CONTRACT'S (ID-12 DV-4, c0c):
+    // kMGPipeSurfaceKindNone / ...Texture / ...Renderbuffer live in MG_Pipe/MGPipeTypes.h under
+    // exactly these names with the same MGPipeKind derivation and the same static_assert. This
+    // package's copies were a redefinition in the same namespace and are deleted.
+
+    // The upload target an attachment names, RESOLVED: an attachment made through an entry
+    // point that carries no face token stores TextureUploadTarget::Unknown, and the record goes
+    // out fully resolved - nothing in it may require a lookup on the far side.
+    //
+    // THE FALLBACK IS ONLY LEGAL FOR A SINGLE-TARGET TEXTURE (m1), and v1's was not. The
+    // precedent it copied - FramebufferAttachmentObject::GetSize - needs an EXTENT, which is
+    // identical across a cube map's six faces; face IDENTITY is not, so
+    // `glFramebufferTexture(GL_COLOR_ATTACHMENT0, cube, 0)` resolved to targets[0] and the
+    // record ASSERTED CubeMapPositiveX for a layered attachment that names all six. A texture
+    // with exactly one upload target has a [0] that IS the truth; anything else keeps Unknown,
+    // which is the value the field already carries for "this attachment names no single face"
+    // and which Layered = 1 tells the reader to ignore.
+    inline MobileGL::TextureUploadTarget MGPipeResolveAttachmentUploadTarget(
+        const MG_State::GLState::FramebufferAttachmentObject& attachment) {
+        MobileGL::TextureUploadTarget resolved = attachment.GetTextureUploadTarget();
+        if (resolved != MobileGL::TextureUploadTarget::Unknown) return resolved;
+        const auto& texture = attachment.GetTexture();
+        if (!texture) return MobileGL::TextureUploadTarget::Unknown;
+        const auto& targets = texture->GetUploadTargets();
+        return targets.size() == 1 ? targets[0] : MobileGL::TextureUploadTarget::Unknown;
+    }
+
+    // ONE PURE FUNCTION, ONE STATEMENT PER FIELD, and that shape is a gate requirement rather
+    // than taste: G7's scripted control stops this conversion copying exactly one member
+    // (MGPSurface::Layered) and expects the framebuffer suite to go red NAMING that field. A
+    // loop or a memcpy would make the control unanswerable.
+    //
+    // `res` is handed in because resolving it needs the slot allocator and this function stays
+    // pure; `internalFormat` is INLINE in the record on purpose, so the four cross-object masks
+    // fall out at push time with no lookup on the far side.
+    // THE EMPTY POINT IS THE ZERO-INITIALISED RECORD EXCEPT FOR ITS TWO TARGET FIELDS. Both
+    // are Uint16 enumerations whose zero is a REAL value - TextureTarget::Texture1D and
+    // TextureUploadTarget::Texture1D - so a reader that forgot to gate on Kind would read a
+    // plausible wrong answer rather than a nonsense one. Unknown (0xFFFF) is what the contract
+    // spells for TextureTarget (kMGPipeSurfaceNoTextureTarget) and m6 applies the same rule to
+    // UploadTarget, which shares the collision ID-12 DV-3 ruled on for MGPSubData::Target.
+    inline MGPSurface MGPipeEmptySurface() {
+        MGPSurface surface{};
+        surface.UploadTarget = static_cast<Uint16>(MobileGL::TextureUploadTarget::Unknown);
+        surface.TextureTarget = kMGPipeSurfaceNoTextureTarget;
+        return surface;
+    }
+
+    inline MGPSurface MGPipeBuildSurface(const MG_State::GLState::FramebufferAttachmentObject& attachment,
+                                         MGPipeHandle res) {
+        MGPSurface surface = MGPipeEmptySurface();
+        if (attachment.IsEmpty()) return surface;
+        surface.Res = res;
+        if (attachment.IsTexture()) {
+            const auto& texture = attachment.GetTexture();
+            surface.Kind = kMGPipeSurfaceKindTexture;
+            surface.InternalFormat = static_cast<Uint32>(texture->GetFormat());
+            surface.Layered = attachment.IsLayered() ? 1 : 0;
+            surface.Level = static_cast<Uint16>(std::max<Int>(attachment.GetTextureLevel(), 0));
+            surface.Layer = static_cast<Uint32>(std::max<Int>(attachment.GetTextureLayer(), 0));
+            surface.UploadTarget = static_cast<Uint16>(MGPipeResolveAttachmentUploadTarget(attachment));
+            // ID-12 DV-5: the field that WAS Pad0, and the size did not move. The four
+            // cross-object masks all reduce to (format, TEXTURE TARGET) -
+            // ShouldUseCaveatTextureFormat / BackendTextureFormatAddsAlpha - and no
+            // TextureUploadTarget -> TextureTarget inverse exists anywhere in the tree, so
+            // without this the inline InternalFormat cannot make them fall out at push time and
+            // the backend keeps reading the frontend attachment objects.
+            surface.TextureTarget = static_cast<Uint16>(texture->GetTarget());
+            return surface;
+        }
+        const auto& renderbuffer = attachment.GetRenderbuffer();
+        surface.Kind = kMGPipeSurfaceKindRenderbuffer;
+        surface.InternalFormat = static_cast<Uint32>(renderbuffer->GetInternalFormat());
+        surface.Layered = 0;
+        surface.Level = 0;
+        surface.Layer = 0;
+        return surface;
+    }
+
+    // MGPFramebufferState::DrawBuffers[i]: an index INTO THIS RECORD'S OWN Color[] array, and
+    // -1 for NONE, which is the field's documented convention read literally.
+    //
+    // THE FOUR DEFAULT-FRAMEBUFFER TOKENS map to 0, and that is a deliberate narrowing rather
+    // than an oversight: a default framebuffer has one colour surface, this record carries it
+    // in Color[0] (see MGPipeBuildFramebufferState), and IsDefault is what tells the server
+    // which framebuffer it is looking at. The distinction the narrowing loses is FRONT versus
+    // BACK and LEFT versus RIGHT, which MobileGL's frontend never gives a default framebuffer
+    // in the first place - FramebufferObject's constructor seeds BackLeft and nothing writes
+    // another. A phase that needs stereo has to widen the field, not re-encode this one.
+    inline Int8 MGPipeDrawBufferIndex(MobileGL::FramebufferAttachmentType buffer) {
+        using MobileGL::FramebufferAttachmentType;
+        if (buffer == FramebufferAttachmentType::None) return -1;
+        if (buffer >= FramebufferAttachmentType::Color0 && buffer <= FramebufferAttachmentType::ColorMax) {
+            return static_cast<Int8>(static_cast<Int>(buffer) - static_cast<Int>(FramebufferAttachmentType::Color0));
+        }
+        return 0;
+    }
+
+    // m2: A DRAW-BUFFER TOKEN CAN NAME A COLOUR POINT THE RECORD CANNOT CARRY, and D-C3's
+    // refusal loop only ever scanned ATTACHMENTS. `glDrawBuffers(1, {GL_COLOR_ATTACHMENT10})`
+    // with nothing attached at 10 is legal state - draw-incomplete, but legal - and the index
+    // above would have written 10 into a record whose Color[] is 8 wide, so the server would
+    // index out of its own storage or invent a bound the record does not carry. Truncating
+    // silently is the bug class this phase is closing, so the record is refused exactly as an
+    // over-wide attachment is.
+    inline Bool MGPipeDrawBufferIsInsideTheWireWidth(MobileGL::FramebufferAttachmentType buffer) {
+        using MobileGL::FramebufferAttachmentType;
+        if (buffer < FramebufferAttachmentType::Color0 || buffer > FramebufferAttachmentType::ColorMax) {
+            return true; // None and the four default-framebuffer tokens; neither indexes Color[]
+        }
+        return static_cast<Int>(buffer) - static_cast<Int>(FramebufferAttachmentType::Color0) <
+               static_cast<Int>(kMGPipeMaxColorAttachments);
+    }
+
+    // ---------------------------------------------------------------------------------
+    // D-C4: ContentHash, and the one input it must not swallow
+    // ---------------------------------------------------------------------------------
+    //
+    // XXH64 over the WHOLE record with ContentHash itself zeroed, computed field-wise into a
+    // zero-initialised staging copy so that no padding byte can enter the hash. Two jobs: the
+    // server's render-pass memo key, and this client's emission suppressor.
+    //
+    // IT MUST COVER Fbo. A recycled framebuffer handle whose successor happens to carry an
+    // identical attachment set would otherwise be suppressed against its predecessor; Fbo
+    // carries Gen, so it cannot be.
+    //
+    // IT MUST COVER DrawBuffers[8], and this is the trap worth naming. The backend derives the
+    // fragColor BROADCAST COUNT from the draw-buffer array, and it does that at the verb, from
+    // the framebuffer state it then holds, precisely so a program can relink inside the same
+    // draw. A hash that did not cover the array would let a suppressed set_framebuffer_state
+    // mean "the draw buffers did not move" when they had, and the shader would be specialised
+    // for the previous output shape. With the array in the hash, a suppression provably means
+    // the array did not move, which provably means the broadcast count did not move.
+    inline void MGPipeCopySurfaceForHash(MGPSurface& dst, const MGPSurface& src) {
+        dst.Res = src.Res;
+        dst.InternalFormat = src.InternalFormat;
+        dst.Kind = src.Kind;
+        dst.Layered = src.Layered;
+        dst.Level = src.Level;
+        dst.Layer = src.Layer;
+        dst.UploadTarget = src.UploadTarget;
+        // MANDATORY, not optional: TextureTarget is a PipeFields.def row now, so a
+        // field-wise copy that skipped it would suppress a record whose only moved field is
+        // the attachment's texture target - and that field decides three of the four
+        // cross-object masks.
+        dst.TextureTarget = src.TextureTarget;
+    }
+
+    inline Uint64 MGPipeFramebufferStateContentHash(const MGPFramebufferState& state) {
+        MGPFramebufferState staging{};
+        staging.Fbo = state.Fbo;
+        for (SizeT i = 0; i < kMGPipeMaxColorAttachments; ++i) {
+            MGPipeCopySurfaceForHash(staging.Color[i], state.Color[i]);
+        }
+        MGPipeCopySurfaceForHash(staging.Depth, state.Depth);
+        MGPipeCopySurfaceForHash(staging.Stencil, state.Stencil);
+        MGPipeCopySurfaceForHash(staging.ReadSurface, state.ReadSurface);
+        for (SizeT i = 0; i < kMGPipeMaxColorAttachments; ++i) {
+            staging.DrawBuffers[i] = state.DrawBuffers[i];
+        }
+        staging.Width = state.Width;
+        staging.Height = state.Height;
+        staging.Layers = state.Layers;
+        staging.Samples = state.Samples;
+        staging.FixedSampleLocations = state.FixedSampleLocations;
+        staging.IsDefault = state.IsDefault;
+        staging.Complete = state.Complete;
+        staging.Target = state.Target;
+        // staging.ContentHash stays 0 - that is the whole point.
+        return XXH64(&staging, sizeof(staging), 0);
+    }
+
+    // ---------------------------------------------------------------------------------
+    // The emitter
+    // ---------------------------------------------------------------------------------
+
+    class MGPipeFramebufferEmitter {
+    public:
+        using GLContext = MG_State::GLState::GLContext;
+        using FramebufferObject = MG_State::GLState::FramebufferObject;
+        using FramebufferAttachmentType = MobileGL::FramebufferAttachmentType;
+
+        // The handle for `fbo`. kMGPipeDefaultFramebuffer ({0,1}) for the default framebuffer,
+        // which is what retires the four pDefaultFramebufferInfo->defaultFBO identity
+        // comparisons into an ordinary handle compare; a client-minted {slot, gen} otherwise.
+        //
+        // Minted, never gated: a framebuffer handle is CLIENT state and costs one free-list pop.
+        static MGPipeHandle HandleFor(const FramebufferObject& fbo) {
+            if (fbo.IsDefaultFramebuffer()) return kMGPipeDefaultFramebuffer;
+            return MGPipeSlots().Acquire(MGPipeKind::Framebuffer, fbo.GetLifetimeId());
+        }
+
+        // Returns the bytes that went on the wire, for the per-draw payload histogram.
+        Uint64 EmitFramebufferState(GLContext& ctx) {
+            if (!MGPipeFramebufferSubsystemEnabled()) return 0;
+            const auto& drawFbo = ctx.GetFramebufferBindingSlot(MobileGL::FramebufferTarget::Draw).GetBoundObject();
+            const auto& readFbo = ctx.GetFramebufferBindingSlot(MobileGL::FramebufferTarget::Read).GetBoundObject();
+            if (!drawFbo && !readFbo) return 0;
+
+            // ONE OBJECT BOUND TO BOTH TARGETS IS ONE RECORD WITH Target = Both, and that is
+            // not an optimisation: Espryt's "same FBO as draw" skip is the habitat of the
+            // read-buffer defect class, and a record that says which target it describes turns
+            // "apply the draw buffers only for the draw target" from call-site discipline into
+            // a one-line test on the far side.
+            const Bool shared = drawFbo && readFbo && drawFbo.get() == readFbo.get();
+
+            MGPFramebufferState drawState{};
+            MGPFramebufferState readState{};
+            Bool drawOk = false;
+            Bool readOk = false;
+            if (shared) {
+                drawOk = BuildFramebufferState(*drawFbo, MGPipeFramebufferTarget::Both, drawState);
+            } else {
+                if (drawFbo) {
+                    drawOk = BuildFramebufferState(*drawFbo, MGPipeFramebufferTarget::Draw, drawState);
+                }
+                if (readFbo) {
+                    readOk = BuildFramebufferState(*readFbo, MGPipeFramebufferTarget::Read, readState);
+                }
+            }
+            if (!drawOk && !readOk) return 0;
+
+            // THE SUPPRESSOR SLOT IS FED THE COMBINED ANSWER and the per-target latches decide
+            // which of the two records actually goes out. The slot exists so that
+            // InvalidateAll() on a fresh context reaches this family like every other, and so
+            // that "nothing moved" costs one compare rather than two.
+            const Uint64 drawHash = drawOk ? drawState.ContentHash : 0;
+            const Uint64 readHash = readOk ? readState.ContentHash : 0;
+            const Uint64 combined =
+                MGPipeMixShutter(MGPipeMixShutter(drawHash, readHash), shared ? 1u : 0u);
+            if (!MGPipeSetHashSuppressorInstance().ShouldEmit(MGPipeSuppressorSlot::SetFramebufferState,
+                                                             combined)) {
+                return 0;
+            }
+
+            Uint64 bytes = 0;
+            if (shared) {
+                if (drawOk && (drawHash != m_lastEmitted[kDraw] || drawHash != m_lastEmitted[kRead])) {
+                    bytes += Emit(drawState);
+                    m_lastEmitted[kDraw] = drawHash;
+                    m_lastEmitted[kRead] = drawHash;
+                }
+                return bytes;
+            }
+            if (drawOk && drawHash != m_lastEmitted[kDraw]) {
+                bytes += Emit(drawState);
+                m_lastEmitted[kDraw] = drawHash;
+            }
+            if (readOk && readHash != m_lastEmitted[kRead]) {
+                bytes += Emit(readState);
+                m_lastEmitted[kRead] = readHash;
+            }
+            return bytes;
+        }
+
+        // ID-19(c): EVERY DSA ENTRY POINT THAT HANDS A FRAMEBUFFER TO THE SERVER BY NAME IS
+        // PRECEDED BY A RECORD FOR IT, and that is the phase's main correction rather than a
+        // nicety. With only the two BOUND-target records, glClearNamedFramebufferfv(fbo) on an
+        // unbound fbo made the backend mint a fresh driver framebuffer with NO ATTACHMENTS,
+        // find no record for it, decline, and issue the clear against it anyway -
+        // GL_INVALID_FRAMEBUFFER_OPERATION and nothing cleared, where the legacy arm cleared
+        // correctly (esprytobj C-1).
+        //
+        // THE TARGET IS Named ONLY WHEN THE OBJECT IS BOUND TO NEITHER BINDING. A record always
+        // writes FramebufferRecords[Fbo.Slot]; Draw/Read/Both ADDITIONALLY set the bound
+        // handle(s). So handing a currently-bound framebuffer a Named record would overwrite
+        // the bound record's Target with one that says "no binding" while BoundFramebuffer
+        // still names it, and the server would read a record whose Target contradicts the
+        // binding it is resolved through. Re-asserting the binding the object already has is
+        // free (the content hash suppresses it) and keeps the two consistent.
+        //
+        // Returns the bytes that went on the wire.
+        Uint64 EmitFramebufferByName(const FramebufferObject& fbo) {
+            if (!MGPipeFramebufferSubsystemEnabled()) return 0;
+            MGPipeFramebufferTarget target = MGPipeFramebufferTarget::Named;
+            const Bool boundToDraw = IsBoundTo(fbo, MobileGL::FramebufferTarget::Draw);
+            const Bool boundToRead = IsBoundTo(fbo, MobileGL::FramebufferTarget::Read);
+            if (boundToDraw && boundToRead) {
+                target = MGPipeFramebufferTarget::Both;
+            } else if (boundToDraw) {
+                target = MGPipeFramebufferTarget::Draw;
+            } else if (boundToRead) {
+                target = MGPipeFramebufferTarget::Read;
+            }
+
+            MGPFramebufferState state{};
+            if (!BuildFramebufferState(fbo, target, state)) return 0;
+
+            // THE SUPPRESSOR IS KEYED BY THE FRAMEBUFFER THE RECORD NAMES, never by one global
+            // slot (MGPipeTypes.h states the rule): two different objects' Named records in a
+            // row must both go out, and a Named record must never be suppressed against the
+            // same object's bound record or the reverse. Target is a ContentHash input, so the
+            // second half holds by construction; the per-object table is what buys the first.
+            // The two BOUND latches stay what they are - "does the server's draw/read binding
+            // already hold this record" - and a bound-target emission from here consults them,
+            // because a rebind of an unchanged object must still move the binding.
+            if (target == MGPipeFramebufferTarget::Named) {
+                NamedEntry& entry = NamedEntryFor(state.Fbo);
+                if (entry.Has && entry.Gen == state.Fbo.Gen && entry.LastHash == state.ContentHash) {
+                    return 0;
+                }
+                const Uint64 bytes = Emit(state);
+                entry.Has = true;
+                entry.Gen = state.Fbo.Gen;
+                entry.LastHash = state.ContentHash;
+                return bytes;
+            }
+            if (target == MGPipeFramebufferTarget::Both) {
+                if (state.ContentHash == m_lastEmitted[kDraw] && state.ContentHash == m_lastEmitted[kRead]) {
+                    return 0;
+                }
+                const Uint64 bytes = Emit(state);
+                m_lastEmitted[kDraw] = state.ContentHash;
+                m_lastEmitted[kRead] = state.ContentHash;
+                return bytes;
+            }
+            const SizeT slot = target == MGPipeFramebufferTarget::Read ? kRead : kDraw;
+            if (state.ContentHash == m_lastEmitted[slot]) return 0;
+            const Uint64 bytes = Emit(state);
+            m_lastEmitted[slot] = state.ContentHash;
+            return bytes;
+        }
+
+        // ---- what a unit case reads. The emitter builds INTO these and hands the applier the
+        // same objects, so "what was emitted" costs no copy. ----
+        // ---- the death half (P4a final review C-2) ----
+        //
+        // Called by the contract's death helper before the slot is freed (there is no wire
+        // delete for this kind, D-I2, so this is the only client-side thing a framebuffer's
+        // death has to do). The per-object Named latch is the entry: a recycled handle's Gen
+        // already refuses the stale latch, so this is hygiene rather than a fix - the rule
+        // (ID-8) is that whatever mints a handle retires everything it keeps under it at the
+        // death, and every P4a kind takes the same shape. Gen-keyed for a late notice.
+        void NoteFramebufferDied(MGPipeHandle handle) {
+            const SizeT slot = handle.Slot;
+            if (MGPipeHandleIsNull(handle) || slot >= m_named.size()) return;
+            if (m_named[slot].Gen == handle.Gen) m_named[slot] = NamedEntry{};
+        }
+        // "Does this emitter hold a Named-record latch for this handle at its generation."
+        Bool NamedRecordIsLatched(MGPipeHandle handle) const {
+            const SizeT slot = handle.Slot;
+            if (MGPipeHandleIsNull(handle) || slot >= m_named.size()) return false;
+            return m_named[slot].Has && m_named[slot].Gen == handle.Gen;
+        }
+
+        const MGPFramebufferState& LastDraw() const { return m_lastDraw; }
+        const MGPFramebufferState& LastRead() const { return m_lastRead; }
+        const MGPFramebufferState& LastNamed() const { return m_lastNamed; }
+        Uint64 EmissionCount() const { return m_emissions; }
+        Uint64 RefusedCount() const { return m_refusals; }
+
+        // A fresh context: what the server has is no longer what this emitter last sent. Only
+        // LATCHES reset here - MGPipeApplierReset clears the applier's DrawFramebuffer and
+        // ReadFramebuffer working state, so these mirrors have to go with them or the first
+        // emission after a make-current would be suppressed as unchanged and the server would
+        // draw into the previous context's framebuffer. The suppressor slot is invalidated by
+        // the validate point's own InvalidateAll(), beside this call.
+        void Reset() {
+            m_lastEmitted[kDraw] = 0;
+            m_lastEmitted[kRead] = 0;
+            // The per-object latch goes too, and the safe direction is why: MGPipeApplierReset
+            // keeps FramebufferRecords standing (they are object state, ID-19(b)) but
+            // ReleaseObjectRecords clears the whole table, and this emitter cannot tell the two
+            // scopes apart from here. Keeping a latch across a table that may have been dropped
+            // would suppress the one record that had to go out; dropping it costs one extra
+            // 304-byte record per named framebuffer after a context switch.
+            m_named.clear();
+        }
+
+        void ResetCounters() { m_emissions = m_refusals = 0; }
+
+        void ResetForTest() {
+            Reset();
+            ResetCounters();
+            m_lastDraw = MGPFramebufferState{};
+            m_lastRead = MGPFramebufferState{};
+            m_lastNamed = MGPFramebufferState{};
+        }
+
+    private:
+        static constexpr SizeT kDraw = 0;
+        static constexpr SizeT kRead = 1;
+
+        Uint64 Emit(const MGPFramebufferState& state) {
+            if (state.Target == static_cast<Uint8>(MGPipeFramebufferTarget::Named)) {
+                m_lastNamed = state;
+            } else if (state.Target == static_cast<Uint8>(MGPipeFramebufferTarget::Read)) {
+                m_lastRead = state;
+            } else {
+                m_lastDraw = state;
+                if (state.Target == static_cast<Uint8>(MGPipeFramebufferTarget::Both)) m_lastRead = state;
+            }
+            MGPipeApplySetFramebufferState(state);
+            ++m_emissions;
+            if (MG_Util::PipeStats::Enabled()) {
+                MG_Util::PipeStats::AddCalls(MG_Util::PipeStats::CallClass::FramebufferEmissions, 1);
+            }
+            return sizeof(MGPFramebufferState);
+        }
+
+        // ONE RECORD DESCRIBES ONE FRAMEBUFFER OBJECT - the one named by `fbo` - and every
+        // field in it is a property of THAT object. Target is the only binding-specific one.
+        //
+        // ReadSurface IS RESOLVED FROM THIS FRAMEBUFFER'S OWN READ BUFFER UNDER EVERY TARGET,
+        // Named included (c0e / MGPipeTypes.h). v1 resolved a Draw record's ReadSurface from
+        // the READ-bound object, which was D-C2's letter and muddled in substance: the record
+        // then described a surface that is not part of the framebuffer its own Fbo names, and a
+        // glReadBuffer on the read FBO moved the DRAW record's ContentHash and forced a
+        // redundant draw emission. Resolving it per object is what makes the
+        // read-buffer-shared-FBO defect class unrepresentable rather than merely fixed - the
+        // record carries a surface, not an index, and no field of it refers to "whatever is
+        // bound".
+        Bool BuildFramebufferState(const FramebufferObject& fbo, MGPipeFramebufferTarget target,
+                                   MGPFramebufferState& out) {
+            // D-C3, THE CLIENT HALF OF THE BRING-UP REFUSAL. The wire array is 8 wide and
+            // GetDynamicParameters().MaxColorAttachments is the driver's raw ES cap, not
+            // clamped to 8 on the GLES path. An attachment point at or above the wire width
+            // cannot be carried at all, so the record is REFUSED and the legacy arm runs -
+            // truncating it silently is exactly the bug class this phase is closing. The
+            // backend half of the same refusal (bit 9 declined at its first lookup, with one
+            // ERROR naming the cap) rides ResolveFramebufferSubsystemArm.
+            for (Int point = static_cast<Int>(FramebufferAttachmentType::Color0) +
+                             static_cast<Int>(kMGPipeMaxColorAttachments);
+                 point <= static_cast<Int>(FramebufferAttachmentType::ColorMax); ++point) {
+                if (fbo.GetAttachment(static_cast<FramebufferAttachmentType>(point)).IsEmpty()) continue;
+                MGLOG_E_ONCE("MGPipe: framebuffer %u has an attachment at colour point %d, which is at or "
+                             "above the wire width of %u - set_framebuffer_state is refused rather than "
+                             "truncated and the legacy arm runs",
+                             fbo.GetExternalIndex(),
+                             point - static_cast<Int>(FramebufferAttachmentType::Color0),
+                             static_cast<Uint>(kMGPipeMaxColorAttachments));
+                ++m_refusals;
+                return false;
+            }
+
+            // m2, THE SAME REFUSAL ONE FIELD OVER. A draw-buffer token may name a colour point
+            // at or above the wire width with nothing attached there, which the loop above
+            // cannot see; MGPipeDrawBufferIndex would then write 8..31 into an 8-wide array.
+            {
+                const auto& tokens = fbo.GetDrawBuffers();
+                for (SizeT i = 0; i < kMGPipeMaxColorAttachments; ++i) {
+                    if (MGPipeDrawBufferIsInsideTheWireWidth(tokens[i])) continue;
+                    MGLOG_E_ONCE("MGPipe: framebuffer %u names colour point %d in draw buffer %u, which is "
+                                 "at or above the wire width of %u - set_framebuffer_state is refused "
+                                 "rather than truncated and the legacy arm runs",
+                                 fbo.GetExternalIndex(),
+                                 static_cast<Int>(tokens[i]) -
+                                     static_cast<Int>(FramebufferAttachmentType::Color0),
+                                 static_cast<Uint>(i), static_cast<Uint>(kMGPipeMaxColorAttachments));
+                    ++m_refusals;
+                    return false;
+                }
+            }
+
+            out = MGPFramebufferState{};
+            out.Fbo = HandleFor(fbo);
+            out.Target = static_cast<Uint8>(target);
+            out.IsDefault = fbo.IsDefaultFramebuffer() ? 1 : 0;
+
+            // THE COLOUR POINTS. A default framebuffer keeps its one colour surface under
+            // BackLeft rather than under Color0, and the record has exactly one place to put
+            // it: Color[0], which is also the index MGPipeDrawBufferIndex maps that token to,
+            // so the array and the draw-buffer indices agree by construction.
+            if (out.IsDefault != 0) {
+                out.Color[0] = SurfaceOf(fbo, FramebufferAttachmentType::BackLeft);
+            } else {
+                for (SizeT i = 0; i < kMGPipeMaxColorAttachments; ++i) {
+                    out.Color[i] = SurfaceOf(fbo, static_cast<FramebufferAttachmentType>(
+                                                      static_cast<Int>(FramebufferAttachmentType::Color0) +
+                                                      static_cast<Int>(i)));
+                }
+            }
+            out.Depth = SurfaceOf(fbo, FramebufferAttachmentType::Depth);
+            out.Stencil = SurfaceOf(fbo, FramebufferAttachmentType::Stencil);
+            out.ReadSurface = SurfaceOf(fbo, fbo.GetReadBuffer());
+
+            const auto& drawBuffers = fbo.GetDrawBuffers();
+            for (SizeT i = 0; i < kMGPipeMaxColorAttachments; ++i) {
+                out.DrawBuffers[i] = MGPipeDrawBufferIndex(drawBuffers[i]);
+            }
+
+            FillGeometry(fbo, out);
+            // Complete is FramebufferObject::CheckCompleteness(), the FRONTEND-ONLY answer, and
+            // never glCheckFramebufferStatus's: that entry point additionally consults the
+            // backend's probed format-capability cache, and a client emitting it would be
+            // reading the backend from the client side - the exact coupling this boundary
+            // exists to remove. glCheckFramebufferStatus keeps answering from the frontend
+            // exactly as it does today.
+            out.Complete = fbo.CheckCompleteness() ? 1 : 0;
+            out.ContentHash = MGPipeFramebufferStateContentHash(out);
+            return true;
+        }
+
+        static Bool IsBoundTo(const FramebufferObject& fbo, MobileGL::FramebufferTarget target) {
+            if (MG_State::pGLContext == nullptr) return false;
+            const auto& bound = MG_State::pGLContext->GetFramebufferBindingSlot(target).GetBoundObject();
+            return bound && bound.get() == &fbo;
+        }
+
+        struct NamedEntry {
+            Uint32 Gen = 0;
+            Uint64 LastHash = 0;
+            Bool Has = false;
+        };
+
+        NamedEntry& NamedEntryFor(MGPipeHandle fbo) {
+            const SizeT slot = fbo.Slot;
+            if (slot >= m_named.size()) m_named.resize(slot + 1);
+            return m_named[slot];
+        }
+
+        MGPSurface SurfaceOf(const FramebufferObject& fbo, FramebufferAttachmentType type) {
+            if (type == FramebufferAttachmentType::None || type == FramebufferAttachmentType::Unknown) {
+                return MGPipeEmptySurface();
+            }
+            const auto& attachment = fbo.GetAttachment(type);
+            if (attachment.IsEmpty()) return MGPipeEmptySurface();
+            MGPipeTextureEmitter& textures = MGPipeTextureEmitterInstance();
+            // D-A4's two producers: an attachment point is what sets RENDER_TARGET and
+            // DEPTH_STENCIL, the two sticky bind bits nothing set before P4a. Sticky and ORed,
+            // so a texture that was ever a colour attachment keeps saying so, and the mask is
+            // republished on the resource's next respecify.
+            const Uint16 bit = (type == FramebufferAttachmentType::Depth ||
+                                type == FramebufferAttachmentType::Stencil)
+                                   ? static_cast<Uint16>(kMGPipeBindDepthStencil)
+                                   : static_cast<Uint16>(kMGPipeBindRenderTarget);
+            MGPipeHandle res = kMGPipeNullHandle;
+            if (attachment.IsTexture()) {
+                const auto& texture = attachment.GetTexture();
+                res = textures.AcquireTexture(texture->GetLifetimeId(), texture.get());
+                textures.NoteTextureBoundAs(res, bit);
+            } else if (attachment.IsRenderbuffer()) {
+                const auto& renderbuffer = attachment.GetRenderbuffer();
+                res = textures.AcquireRenderbuffer(renderbuffer->GetLifetimeId());
+                textures.NoteRenderbufferBoundAs(res, bit);
+            }
+            return MGPipeBuildSurface(attachment, res);
+        }
+
+        // The attachments' common extent, and the ARB_framebuffer_no_attachments defaults when
+        // there is no attachment at all (GL 4.6 core table 23.24 - the shape a framebuffer with
+        // no attachments rasterizes at).
+        static void FillGeometry(const FramebufferObject& fbo, MGPFramebufferState& out) {
+            Bool found = false;
+            for (const auto& attachment : fbo.GetAllAttachmentObjects()) {
+                if (attachment.IsEmpty()) continue;
+                const IntVec3 size = attachment.GetSize();
+                if (!found) {
+                    out.Width = static_cast<Uint16>(std::clamp<Int>(size.x(), 0, 0xFFFF));
+                    out.Height = static_cast<Uint16>(std::clamp<Int>(size.y(), 0, 0xFFFF));
+                    out.Layers = static_cast<Uint16>(
+                        attachment.IsLayered() ? std::clamp<Int>(size.z(), 1, 0xFFFF) : 1);
+                    if (attachment.IsTexture()) {
+                        const auto& texture = attachment.GetTexture();
+                        out.Samples = static_cast<Uint16>(std::max<Int>(texture->GetSamples(), 0));
+                        out.FixedSampleLocations = texture->HasFixedSampleLocations() ? 1 : 0;
+                    } else {
+                        out.Samples = static_cast<Uint16>(
+                            std::max<Int>(attachment.GetRenderbuffer()->GetSamples(), 0));
+                        out.FixedSampleLocations = 1;
+                    }
+                    found = true;
+                }
+            }
+            if (found) return;
+            out.Width = static_cast<Uint16>(std::clamp<Int>(fbo.GetDefaultWidth(), 0, 0xFFFF));
+            out.Height = static_cast<Uint16>(std::clamp<Int>(fbo.GetDefaultHeight(), 0, 0xFFFF));
+            out.Layers = static_cast<Uint16>(std::clamp<Int>(fbo.GetDefaultLayers(), 0, 0xFFFF));
+            out.Samples = static_cast<Uint16>(std::clamp<Int>(fbo.GetDefaultSamples(), 0, 0xFFFF));
+            out.FixedSampleLocations = fbo.GetDefaultFixedSampleLocations() ? 1 : 0;
+        }
+
+        Array<Uint64, 2> m_lastEmitted{};
+        // The per-FRAMEBUFFER suppressor for Named records, slot-indexed with the generation
+        // checked, exactly as the applier's own table is. A framebuffer has no wire lifetime
+        // (D-I2), so a successor simply overwrites its predecessor's entry.
+        Vector<NamedEntry> m_named;
+        MGPFramebufferState m_lastDraw{};
+        MGPFramebufferState m_lastRead{};
+        MGPFramebufferState m_lastNamed{};
+        Uint64 m_emissions = 0;
+        Uint64 m_refusals = 0;
+    };
+
+    inline MGPipeFramebufferEmitter& MGPipeFramebufferEmitterInstance() {
+        // NEVER DESTROYED, for MGPipeTrackerInstance()' reason (MG_Impl/Pipe/Tracker.h): the
+        // rule covers every MGPipe process singleton, not only the ones a frontend destructor
+        // reaches today, and it is what keeps exit() out of a torn-down pipe.
+        static MGPipeFramebufferEmitter* emitter = new MGPipeFramebufferEmitter();
+        return *emitter;
+    }
+} // namespace MobileGL::MG_Pipe
+#endif // MOBILEGL_PIPE_PUSH

MobileGL/MG_Impl/Pipe/ImageEmit.h

@@ -0,0 +1,182 @@
+// MobileGL - MobileGL/MG_Impl/Pipe/ImageEmit.h
+// Copyright (c) 2025-2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+
+#pragma once
+#include <Includes.h>
+
+// The CLIENT side of set_shader_images, the third of P4a's kVarTail unit sets. It rides
+// SamplerEmit.h's subsystem bit (kMGPipeWiredSamplerSubsystem): one family, one A/B.
+//
+// TWO INVARIANTS THAT MUST SURVIVE INTO THE BODY, and they are the kind an optimisation
+// deletes:
+//   1. THE HIGH-WATER-ZERO EARLY-OUT. An image high-water mark of 0 emits nothing, BEFORE any
+//      hash - that is what makes every Minecraft draw pay one integer test for a feature it
+//      does not use.
+//   2. THE SWEEP'S GATE IS KEYED ON FRONTEND GENERATIONS AND DELIBERATELY NOT ON A BACKEND
+//      RE-MINT COUNTER. A texture bound ONLY to an image unit is re-minted INSIDE the sweep,
+//      so a server-side epoch would be bumped after the gate had already declined. The
+//      client's bit-14 shutter is Mix(Mix(textureContent, textureParams), programImageUnitVersion)
+//      - all three FRONTEND counters - so the property is preserved by construction, and it is
+//      written here because it is invisible from the shutter itself.
+//
+// The record carries the APPLICATION's format and access; the bind-format recast (a GL_RG32F
+// bind is INVALID_VALUE on 19 of 26 non-core formats on Adreno) and the buffer-texture split
+// view stay SERVER-side and unchanged. ContentHash therefore has to cover InternalFormat and
+// Access as well as the binding, because the format the shader was built against is live
+// glBindImageTexture state and the format-less image bake keys on it.
+//
+// THIS FILE IS CREATED BY THE CONTRACT COMMIT AND FILLED BY THE PACKAGE THAT OWNS IT - see
+// FramebufferEmit.h for why, in full.
+#if MOBILEGL_PIPE_PUSH
+#include <MG_Impl/Pipe/SamplerEmit.h>
+#include <MG_Impl/Pipe/SetHashSuppressor.h>
+#include <MG_Impl/Pipe/SlotAllocator.h>
+#include <MG_Pipe/MGPipe.h>
+#include <MG_Pipe/PipeApply.h>
+#include <MG_Pipe/PipeMutation.h>
+#include <MG_State/GLState/Core.h>
+#include <MG_State/GLState/TextureState/TextureState.h>
+#include <MG_Util/Metrics/PipeStats.h>
+
+#include <xxhash.h>
+
+namespace MobileGL::MG_Pipe {
+
+    // D-G3. Over the tail with Start and Count mixed in, the same shape the two sampler sets
+    // use - and it covers InternalFormat and Access because those are live glBindImageTexture
+    // state that the format-less image bake keys on, not decoration.
+    inline Uint64 MGPipeShaderImageSetContentHash(const MGPImageView* entries, Uint32 start, Uint32 count) {
+        Uint64 hash = XXH64(entries, static_cast<SizeT>(count) * sizeof(MGPImageView), 0);
+        hash = MGPipeMixShutter(hash, start);
+        hash = MGPipeMixShutter(hash, count);
+        return hash;
+    }
+
+    class MGPipeImageEmitter {
+    public:
+        using GLContext = MG_State::GLState::GLContext;
+
+        // set_shader_images. Start is 0 and Count is the image-unit window described below.
+        //
+        // WHERE THE HIGH-WATER MARK COMES FROM, because the frontend has none and this is the
+        // one place a reader will look for it. DirectGLES keeps g_imageUnitHighWaterMark, but
+        // that is written from inside its own per-unit sync and lives on the far side of the
+        // boundary; TextureState::NoteUnitTouched is the TEXTURE-unit path and
+        // glBindImageTexture does not reach it. Adding a counter to TextureState would edit
+        // another package's file and resize the pull build's object, which G1 forbids outright.
+        //
+        // So the window is derived instead, from the one thing that decides whether an image
+        // unit can matter at all: the highest image unit the CURRENT PROGRAM names, memoised
+        // per program state in SamplerEmit.h's shared inversion, UNIONED with a sticky mark of
+        // every unit this emitter has already described. A program with no image uniforms
+        // gives MaxImageUnit == -1 and, with nothing sticky yet, a window of 0 - which is the
+        // zero early-out, taken BEFORE any hash and before any 192-entry walk, exactly as
+        // property 1 requires. The mark is sticky so that a program which stops naming a unit
+        // does not silently stop describing it: the window only grows, and shrinking it is how
+        // a stale binding would become invisible to the server.
+        Uint64 EmitShaderImages(GLContext& ctx) {
+            const auto& program = ctx.GetProgramForDraw();
+            const auto& resolution = MGPipeProgramOpaqueUnitsShared().For(program.get());
+            const Uint32 programWindow =
+                resolution.MaxImageUnit < 0 ? 0u : static_cast<Uint32>(resolution.MaxImageUnit) + 1u;
+            if (programWindow > m_window) m_window = programWindow;
+            const Uint32 count = m_window < kMGPipeMaxImageUnits ? m_window : kMGPipeMaxImageUnits;
+            // PROPERTY 1, and it is one integer test on every draw of every application that
+            // never binds an image.
+            if (count == 0) return 0;
+
+            for (Uint32 unit = 0; unit < count; ++unit) {
+                const auto& binding = ctx.GetImageTextureBinding(static_cast<Int>(unit));
+                MGPImageView& entry = m_entries[unit];
+                entry = MGPImageView{};
+                entry.Unit = unit;
+                entry.Res = binding.Texture ? MGPipeSlots().Acquire(MGPipeKind::Texture,
+                                                                    binding.Texture->GetLifetimeId())
+                                            : kMGPipeNullHandle;
+                // D-A4: a texture named in an emitted MGPImageView is SHADER-IMAGE-bound from
+                // then on - the bit ImageBindableHint is derived from. The bind itself noted it
+                // first (TextureState.h, so the hint precedes the first sync); this is the
+                // letter of the rule and a one-compare early-out once the bit is set.
+                if (!MGPipeHandleIsNull(entry.Res)) {
+                    MGPipeNoteTextureBoundAs(entry.Res, static_cast<Uint32>(kMGPipeBindShaderImage));
+                }
+                // THE APPLICATION's format and access, verbatim. The bind-format recast and the
+                // buffer-texture split view are server-side and stay there; so does
+                // SupportsLayeredImageBinding's rule, which asks the BACKEND target after
+                // MapToBackendTextureTarget and forces layer to 0 for a non-layerable one -
+                // Adreno took a stray layer index literally. A client that pre-applied any of
+                // that would be answering a driver question from the wrong side.
+                entry.InternalFormat = static_cast<Uint32>(binding.Format);
+                entry.Layer = static_cast<Uint32>(binding.Layer);
+                entry.Level = static_cast<Uint16>(binding.Level);
+                entry.Layered = binding.Layered != GL_FALSE ? 1 : 0;
+                entry.Access = static_cast<Uint8>(MGPipeEncodeImageAccess(binding.Access));
+            }
+
+            const Uint64 hash = MGPipeShaderImageSetContentHash(m_entries.data(), 0, count);
+            if (!MGPipeSetHashSuppressorInstance().ShouldEmit(MGPipeSuppressorSlot::SetShaderImages, hash)) {
+                return 0;
+            }
+            m_lastImages = MGPShaderImages{};
+            m_lastImages.Start = 0;
+            m_lastImages.Count = count;
+            m_lastImages.ContentHash = hash;
+            MGPipeApplySetShaderImages(m_lastImages, m_entries.data());
+            ++m_imageSets;
+            if (MG_Util::PipeStats::Enabled()) {
+                MG_Util::PipeStats::AddCalls(MG_Util::PipeStats::CallClass::ShaderImageEmissions, 1);
+            }
+            return sizeof(MGPShaderImages) + static_cast<Uint64>(count) * sizeof(MGPImageView);
+        }
+
+        // The validate point's FreshlyPrimed arm. A fresh context is a fresh set of image
+        // bindings, so the sticky window starts over; the suppressor slot this set latches is
+        // invalidated beside this call. There is no record half here at all - set_shader_images
+        // is pure working state and mints no object of its own.
+        void Reset() { m_window = 0; }
+
+        void ResetCounters() { m_imageSets = 0; }
+
+        const MGPShaderImages& LastShaderImages() const { return m_lastImages; }
+        const Array<MGPImageView, kMGPipeMaxImageUnits>& LastImageViews() const { return m_entries; }
+        Uint64 ImageSetCount() const { return m_imageSets; }
+        Uint32 Window() const { return m_window; }
+
+    private:
+        // GL_READ_ONLY / GL_WRITE_ONLY / GL_READ_WRITE folded into the one byte the wire
+        // carries. A value the enum does not name would otherwise truncate silently into a
+        // Uint8, which is the class of bug the descriptors exist to close.
+        static Uint32 MGPipeEncodeImageAccess(GLenum access) {
+            switch (access) {
+            case GL_READ_ONLY:
+                return 0;
+            case GL_WRITE_ONLY:
+                return 1;
+            case GL_READ_WRITE:
+                return 2;
+            default:
+                MOBILEGL_ASSERT(false, "glBindImageTexture access 0x%x is not one of the three GL names",
+                                static_cast<Uint>(access));
+                return 0;
+            }
+        }
+
+        Array<MGPImageView, kMGPipeMaxImageUnits> m_entries{};
+        MGPShaderImages m_lastImages{};
+        Uint32 m_window = 0;
+        Uint64 m_imageSets = 0;
+    };
+
+    inline MGPipeImageEmitter& MGPipeImageEmitterInstance() {
+        // NEVER DESTROYED, for MGPipeTrackerInstance()' reason; heap-constructed and
+        // intentionally leaked at exit, like every other MGPipe process singleton.
+        static MGPipeImageEmitter* emitter = new MGPipeImageEmitter();
+        return *emitter;
+    }
+} // namespace MobileGL::MG_Pipe
+#endif // MOBILEGL_PIPE_PUSH

MobileGL/MG_Impl/Pipe/PipeFill.h

@@ -43,6 +43,33 @@ namespace MobileGL::MG_Pipe {
     // stop where it says it stops (MG_Test/ScopedPipeVerb.h).
     void MGPipeLeaveVerb();
 
+    // PipeFill.cpp. DOES THIS BUILD, ON THIS BACKEND, AT THIS MASK, EMIT FOR THIS P4a FAMILY?
+    // (ID-39, widened by S-3 / ID-41.) The four conjuncts are the operator's per-subsystem bit
+    // in MOBILEGL_PIPE_PUSH, the family's own kMGPipeWired*Subsystem constant (`wired`, which
+    // the caller passes because it lives in the family's emit header and this header may not
+    // include one), and - for the four families P4a migrates - a backend having registered
+    // MGPipeResourceOps (the same per-backend signal `MGPipeResourceSubsystemEnabled()` has
+    // applied to P3a's buffers since the phase began) and every D-K2 dependency bit of the
+    // family being set in the same mask.
+    //
+    // THE LAST TWO CONJUNCTS ARE THE ONES THIS DECLARATION EXISTS FOR, and they are the same
+    // defect twice. Magma (DirectVulkan) registers no table and has no P4a twins; at a mask like
+    // 0x7ff Espryt REFUSES the texture family server-side because D-K2's fourth row says bit 10
+    // requires bit 11. In both cases the client emitted anyway, the applier accepted, the
+    // emitters cleared their per-level dirty flags on that acceptance, and the legacy upload
+    // path that still owed those texels found nothing to upload (66 DirectVulkan cases at ID-39,
+    // 47 DirectGLES cases at ID-41). With them the four families emit NOTHING in that state and
+    // the legacy pull path runs exactly as it does on a pull build.
+    //
+    // D-K2's TABLE IS IN PipeFill.cpp, ONCE: bit 9 requires bit 10, bit 10 requires bits 7 and
+    // 11, bit 11 requires bit 10, bit 12 depends on nothing - the client mirror, bit for bit, of
+    // the four `Resolve<Family>SubsystemArm()` refusals in DirectGLES/Managers.cpp.
+    //
+    // It is exported for the unit gate and for no other caller: the gate itself is
+    // FamilyIsLive() inside PipeFill.cpp, every birth hook and every `wants()` row resolves
+    // through it, and this returns that same expression rather than a second copy of it.
+    Bool MGPipeP4aFamilyEmits(Uint64 subsystem, Uint64 wired);
+
     // PipeFill.cpp. P3a D-H2.1: the DRAW's raw vertex-fetch base instance, which
     // set_vertex_buffers now carries as an explicit field.
     //

MobileGL/MG_Impl/Pipe/ProgramEmit.h

@@ -0,0 +1,484 @@
+// MobileGL - MobileGL/MG_Impl/Pipe/ProgramEmit.h
+// Copyright (c) 2025-2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+
+#pragma once
+#include <Includes.h>
+
+// The CLIENT side of P4a's program family: create/bind/delete_shader_state,
+// set_draw_program, set_dispatch_program and set_global_constants.
+//
+// WHERE create_shader_state IS EMITTED FROM, and why it is not the tracker's business: the
+// tracker's bit-6 shutter reads GetCurrentProgram() and DELIBERATELY NOT GetProgramForDraw(),
+// because the tracker must not force a compile just to answer "did the shader move". So the
+// tracker keeps its shutter and the EMITTER joins - from the same GetProgramForDraw() /
+// GetProgramForDispatch() call the verb is about to make anyway, so no join happens that would
+// not have happened. Emitting from the compile pool's terminal continuation is a real
+// asynchronous win and is a LATER phase's: in monolith the applier is one function call away,
+// so it is unmeasurable here.
+//
+// WHAT THE SERVER STILL SPECIALISES, so nobody reads create_shader_state as self-contained
+// and produces a per-draw rebuild: the draw-FBO clamp masks, the fragColor broadcast count,
+// the storage-block binding signature, the atomic-counter set, the live image formats and the
+// patch parameters are all inputs a backend program depends on BEYOND the artefacts. This call
+// publishes the ARTEFACTS; the server specialises at the verb from the state it holds. The
+// clause count does not shrink - its inputs move.
+//
+// THE ARTEFACTS DO NOT TRAVEL IN MONOLITH. All seven of MGPProgramDesc's blob refs are
+// declared with Size 0 and the LinkArtifacts / SpirvArtifacts ride beside the record through
+// MGPipeApplyCreateShaderState's companion pointers, so the codec is never called on the hot
+// path; the verify build is where it is exercised.
+//
+// THIS FILE IS CREATED BY THE CONTRACT COMMIT AND FILLED BY THE PACKAGE THAT OWNS IT - see
+// FramebufferEmit.h for why, in full.
+#if MOBILEGL_PIPE_PUSH
+#include <MG_Impl/Pipe/CompositeResolver.h>
+#include <MG_Impl/Pipe/SlotAllocator.h>
+#include <MG_Pipe/MGPipe.h>
+#include <MG_Pipe/MGPipeHostSpan.h>
+#include <MG_Pipe/PipeApply.h>
+#include <MG_Pipe/PipeMutation.h>
+#include <MG_State/GLState/Core.h>
+#include <MG_State/GLState/ProgramState/ProgramObject.h>
+#include <MG_Util/Metrics/PipeStats.h>
+
+namespace MobileGL::MG_Pipe {
+
+    // WIRED. create/bind/delete_shader_state, set_draw_program, set_dispatch_program and
+    // set_global_constants all have bodies, so this family contributes its bit to
+    // kMGPipeWiredSubsystems.
+    //
+    // AND SINCE c0b THAT CONSTANT REALLY IS PART OF THE EMISSION GATE, so the note that used to
+    // say otherwise here was true only against the contract commit: the validate point's
+    // `wants()` asks the subsystem mapping, the operator's MOBILEGL_PIPE_PUSH mask, THIS
+    // CONSTANT and the dirty bit, and the birth hooks' `FamilyIsLive` asks the same pair one
+    // level in. It is also a compile-time contract - while it is non-zero PipeFill.cpp's
+    // `if constexpr` seam instantiates the forward to EmitShaderCso below, so a missing entry
+    // point is a build error here rather than at the merge. The RUNTIME A/B that switches the
+    // family off is still the mask. See SamplerEmit.h's twin note.
+    inline constexpr Uint64 kMGPipeWiredProgramSubsystem = kMGPipeSubsystemPrograms;
+
+    // D-H6. ~0u is the BACKENDS' "never uploaded" sentinel for a global-constants version, and
+    // ProgramObject::MarkUBOContentDirty skips it on the wrap for exactly that reason. The
+    // client must never put it on the wire either: a server that received it would read its own
+    // record as "nothing has ever been uploaded here" and re-upload for ever.
+    inline constexpr Uint32 kMGPipeGlobalConstantsNeverUploaded = ~Uint32{0};
+
+    inline constexpr Bool MGPipeGlobalConstantsVersionIsEmittable(Uint32 version) {
+        return version != kMGPipeGlobalConstantsNeverUploaded;
+    }
+
+    // A program's identity for the wire, out of the SNAPSHOT the last link consumed and never
+    // out of the live attach list: glAttachShader and glCompileShader take effect only at the
+    // NEXT link and neither moves m_linkVersion, so a stage mask built from GetAttachedShaders
+    // would describe a program that does not exist yet. GetLinkedShaderStages() is also what
+    // indexes GetGeneratedSpirv(), so the two halves of this descriptor are guaranteed to agree
+    // by construction rather than by care.
+    inline Uint32 MGPipeStageMaskOf(const MG_State::GLState::ProgramObject& program) {
+        Uint32 mask = 0;
+        for (const ShaderStage stage : program.GetLinkedShaderStages()) {
+            if (stage == ShaderStage::Unknown) continue;
+            mask |= Uint32{1} << static_cast<Uint32>(stage);
+        }
+        return mask;
+    }
+
+    class MGPipeProgramEmitter {
+    public:
+        using GLContext = MG_State::GLState::GLContext;
+        using ProgramObject = MG_State::GLState::ProgramObject;
+
+        // create_shader_state (re-issued on the SAME handle whenever the link version moves -
+        // Gen moves only on slot reuse), then bind_shader_state and set_draw_program /
+        // set_dispatch_program. Two program calls because the frontend has two joins and two
+        // PipeInputs slots.
+        //
+        // BOTH JOINS HAPPEN HERE and both are the verb's own: GetProgramForDraw flattens a
+        // bound pipeline into its composite and GetProgramForDispatch answers the compute
+        // question, and with a plain glUseProgram they are the same object, so the ordinary
+        // frame pays one join it was going to pay anyway.
+        Uint64 EmitShaderState(GLContext& ctx) {
+            Uint64 bytes = 0;
+            const auto& drawProgram = ctx.GetProgramForDraw();
+            const auto& dispatchProgram = ctx.GetProgramForDispatch();
+
+            const MGPipeHandle drawCso =
+                drawProgram ? AcquireShaderCso(*drawProgram, bytes) : kMGPipeNullHandle;
+            // THE COMPOSITE'S SECOND RELEASE PATH is spoken here, not in a destructor: when the
+            // bound pipeline's draw-program signature moves, the resolver releases the slot the
+            // previous composite held. Whichever of the two paths runs second - this one or the
+            // composite ProgramObject's own ~ProgramObject - is a proven no-op, because the slot
+            // allocator refuses a slot that is not live at that generation.
+            if (drawProgram && MGPipeProgramIsPipelineComposite(*drawProgram)) {
+                if (const auto& pipeline = ctx.GetBoundProgramPipeline()) {
+                    // THE CONTEXT IS PART OF THE RESOLVER's KEY and this is the only place that
+                    // supplies it: the resolver is a process singleton and a pipeline's GL name
+                    // is per context, so without it a make-current between two contexts holding
+                    // one pipeline name released the other context's LIVE composite.
+                    // GetTextureContextId() is the tree's never-reused per-context id, the same
+                    // one PipeInputs carries and the backends' per-context memos key on.
+                    MGPipeCompositeResolverInstance().Observe(ctx.GetTextureContextId(), *pipeline,
+                                                             *drawProgram, drawCso);
+                }
+            }
+            const MGPipeHandle dispatchCso =
+                dispatchProgram ? (dispatchProgram == drawProgram ? drawCso
+                                                                  : AcquireShaderCso(*dispatchProgram, bytes))
+                                : kMGPipeNullHandle;
+
+            // THE BOUND CSO IS THE DRAW ONE WHEN THERE IS ONE. bind_shader_state names what
+            // glUseProgram selected, and when a program pipeline is bound instead that is the
+            // composite; a compute-only pipeline has no draw program at all, and then the
+            // dispatch program is the only thing bound. A null handle is legal here and means
+            // exactly "nothing bound".
+            const MGPipeHandle boundCso = !MGPipeHandleIsNull(drawCso) ? drawCso : dispatchCso;
+            if (boundCso != m_boundCso) {
+                MGPipeApplyBindShaderState(HandleOnly(boundCso));
+                m_boundCso = boundCso;
+                ++m_binds;
+                bytes += sizeof(MGPHandleOnly);
+            }
+            if (drawCso != m_drawCso) {
+                MGPipeApplySetDrawProgram(HandleOnly(drawCso));
+                m_drawCso = drawCso;
+                ++m_drawSets;
+                bytes += sizeof(MGPHandleOnly);
+            }
+            if (dispatchCso != m_dispatchCso) {
+                MGPipeApplySetDispatchProgram(HandleOnly(dispatchCso));
+                m_dispatchCso = dispatchCso;
+                ++m_dispatchSets;
+                bytes += sizeof(MGPHandleOnly);
+            }
+            return bytes;
+        }
+
+        // set_global_constants: the DEFAULT UNIFORM BLOCK only, keyed (ShaderCso, Version) and
+        // at most once per program per frame. Version is GetUBOContentVersion() and must never
+        // be ~0u, which is the backends' "never uploaded" sentinel - the wrap skips it.
+        //
+        // NAMED uniform blocks are NOT this call's: set_shader_buffers(Uniform) is a later
+        // phase's and BindCurrentProgramWithResources' named-UBO block is untouched. What
+        // travels here is globalUboScratch, the link phase's CPU array, which has no GL name
+        // and no BufferObject behind it.
+        Uint64 EmitGlobalConstants(GLContext& ctx) {
+            const auto& program = ctx.GetProgramForDraw();
+            if (!program) return 0;
+            const Uint32 version = program->GetUBOContentVersion();
+            // THE SENTINEL IS NEVER EMITTED. A server that received ~0u would read its own
+            // record as "never uploaded" and re-upload every frame for ever.
+            if (!MGPipeGlobalConstantsVersionIsEmittable(version)) return 0;
+            const Uint size = program->GetUBOSize();
+            if (size == 0) return 0;
+
+            Uint64 bytes = 0;
+            const MGPipeHandle cso = AcquireShaderCso(*program, bytes);
+            // (ShaderCso, Version) IS the key, so the latch is the key: an unchanged pair means
+            // the server already holds these bytes and re-sending them would move the record's
+            // serial for nothing.
+            if (cso == m_constantsCso && version == m_constantsVersion) return bytes;
+
+            m_lastConstants = MGPGlobalConstants{};
+            m_lastConstants.ShaderCso = cso;
+            m_lastConstants.Version = version;
+            // THE ONE BLOB RULE: Size 0 means "this record does not declare its blob" - which
+            // is what a monolith emission is - and the bytes ride beside it as a companion
+            // pointer. Offset carries the staging address for diagnostics only; nothing reads
+            // it as a length.
+            m_lastConstants.Blob.Seg = kMGHostSpanSegNone;
+            m_lastConstants.Blob.Offset = reinterpret_cast<Uint64>(program->GetUBOData());
+            m_lastConstants.Blob.Size = 0;
+            MGPipeApplySetGlobalConstants(m_lastConstants, program->GetUBOData());
+            m_constantsCso = cso;
+            m_constantsVersion = version;
+            ++m_constantSets;
+            if (MG_Util::PipeStats::Enabled()) {
+                MG_Util::PipeStats::AddBytes(MG_Util::PipeStats::ByteClass::CsoBlobBytes, size);
+            }
+            return bytes + sizeof(MGPGlobalConstants) + size;
+        }
+
+        // D-H4's re-issue rule, and it is the CreateVertexElements shape one for one: the
+        // record goes out again on the SAME handle whenever the link version moves, which is
+        // legal because MGPipeHandle::Gen increments only on slot reuse and never on a
+        // respecify. A program that relinks is the same GL object and the server's twin table
+        // must not be asked to mint a second one.
+        MGPipeHandle AcquireShaderCso(const ProgramObject& program, Uint64& payloadBytes) {
+            const MGPipeHandle handle = AcquireShaderCsoHandle(program);
+            if (MGPipeHandleIsNull(handle)) return handle;
+            Latch& latch = LatchFor(handle);
+
+            const Uint32 linkVersion = program.GetLinkVersion();
+            if (latch.RecordLive && latch.RecordGen == handle.Gen && latch.LinkVersion == linkVersion) {
+                return handle;
+            }
+
+            const auto& link = program.GetLinkReflection();
+            const auto& spirv = program.GetSpirvReflection();
+
+            m_lastDesc = MGPProgramDesc{};
+            m_lastDesc.Cso = handle;
+            m_lastDesc.StageMask = MGPipeStageMaskOf(program);
+            m_lastDesc.GlobalUboSize = static_cast<Uint32>(program.GetUBOSize());
+            m_lastDesc.ReservedNumSamplesOffset = static_cast<Uint32>(spirv.reservedNumSamplesOffset);
+            m_lastDesc.SpirvStatus = spirv.spirvStatus ? 1 : 0;
+            m_lastDesc.NativeFloat64 = spirv.nativeFloat64 ? 1 : 0;
+            m_lastDesc.PointSizeDemoted = spirv.pointSizeDemoted ? 1 : 0;
+            m_lastDesc.EnableSpirvValidation = spirv.enableSpirvValidation ? 1 : 0;
+
+            // ONE BLOB REF PER MODULE, IN THE LINKED-SHADER-SNAPSHOT'S ORDER, which is the
+            // order GetGeneratedSpirv() is indexed in - so Spirv[i] and StageMask agree because
+            // they came out of the same snapshot. Every one of them declares Size 0 (the one
+            // Blob rule); Offset carries the module's staging address so a reader can see which
+            // slots are occupied without the record pretending to declare a length it does not
+            // own.
+            //
+            // A COUNTED REFUSAL AND NOT AN ASSERTION (D-J3). MOBILEGL_ASSERT compiles out at
+            // INFO, which is all three gate builds and every shipped build, so an assert here
+            // would leave the truncation below completely silent in exactly the builds that
+            // run - which is the idiom D-J3 exists to forbid. generatedSpirv cannot exceed six
+            // stages today, so this is a guard against a seventh; truncation is the safe
+            // direction and the counter is what makes it visible.
+            const SizeT moduleCount = spirv.generatedSpirv.size();
+            if (moduleCount > 6) ++m_moduleTruncations;
+            for (SizeT i = 0; i < moduleCount && i < 6; ++i) {
+                m_lastDesc.Spirv[i].Seg = kMGHostSpanSegNone;
+                m_lastDesc.Spirv[i].Offset = reinterpret_cast<Uint64>(spirv.generatedSpirv[i].data());
+                m_lastDesc.Spirv[i].Size = 0;
+            }
+            m_lastDesc.Reflection.Seg = kMGHostSpanSegNone;
+            m_lastDesc.Reflection.Offset = reinterpret_cast<Uint64>(&link);
+            m_lastDesc.Reflection.Size = 0;
+
+            MGPipeApplyCreateShaderState(m_lastDesc, &link, &spirv);
+            // THE CREATE WENT OUT, so the publication latch is taken here and nowhere else
+            // (contract-v2 §3.1). MGPipeEmitShaderCsoDestroyAndFree reads it, and without it
+            // delete_shader_state can never go out - for an ordinary program or for a
+            // composite, both of which take that one helper.
+            MGPipeNoteHandlePublished(MGPipeKind::ShaderCso, handle);
+            ++m_creates;
+            payloadBytes += sizeof(MGPProgramDesc);
+
+            // A RE-ISSUED create_shader_state CLEARS THE APPLIER's DEFAULT UNIFORM BLOCK (wire
+            // W6), so the (Cso, Version) latch that suppresses set_global_constants has to go
+            // with it or the block is never re-sent. The case the design worries about is a
+            // FAILED relink of a bound program - GL keeps the previous executable and its
+            // uniforms running - and the general one is any future re-issue trigger that does
+            // not happen to move the content version, of which a recycled slot is one.
+            // Invalidated rather than re-emitted here, because this function has no business
+            // deciding when the constants go out: the next EmitGlobalConstants sees an
+            // unlatched key and sends them.
+            if (m_constantsCso == handle) {
+                m_constantsCso = kMGPipeNullHandle;
+                m_constantsVersion = kMGPipeGlobalConstantsNeverUploaded;
+            }
+
+            latch.RecordLive = true;
+            latch.RecordGen = handle.Gen;
+            latch.LinkVersion = linkVersion;
+            return handle;
+        }
+
+        // ---- THE CONTRACT ENTRY POINT THIS FAMILY OWES (contract-v2 §3.4) ----
+        //
+        // PipeFill.cpp's MGPipeEmitShaderCsoCreate forwards here through the `if constexpr`
+        // seam keyed on kMGPipeWiredProgramSubsystem, so while that constant is non-zero this
+        // must exist and be spelled exactly like this. A thin wrapper on purpose:
+        // AcquireShaderCso above IS this family's handle rule - identity-addressed per
+        // ProgramObject, the composite band entered through the one door, the re-issue on the
+        // same handle and the publication - and a second copy of any of it here would be a
+        // second authority.
+        //
+        // THE HOOK HAS ALREADY APPLIED BOTH GATES (the operator's mask and the wired constant),
+        // so this body applies none of its own. The byte count is discarded: a birth is not a
+        // validate-point emission and has no payload budget to report into.
+        void EmitShaderCso(ProgramObject& program) {
+            Uint64 bytes = 0;
+            AcquireShaderCso(program, bytes);
+        }
+
+        // The emitter's OWN record memo - "have I already published a create_shader_state at
+        // this slot, for this generation, at this link version".
+        //
+        // IT IS NOT WHAT THE DEATH PATH ASKS, and that changed at c0b (contract-v2 §3.1/D17):
+        // MGPipeEmitShaderCsoDestroyAndFree reads A's publication latch, which is one answer
+        // per {kind, slot, gen} that all six death helpers share. This stays because the
+        // VERSION-FIRST SKIP needs it - it is the same latch AcquireShaderCso consults before
+        // it builds a descriptor - and because a unit case reads it.
+        //
+        // THE COMPOSITE BAND IS INDEXED SEPARATELY, for the allocator's own reason: the band
+        // base is 983040, so a slot-indexed vector would allocate ~983k latches for one program
+        // pipeline. Both spaces stay dense against their own high-water mark.
+        Bool RecordIsPublished(MGPipeHandle handle) const {
+            if (MGPipeHandleIsNull(handle)) return false;
+            const Vector<Latch>& table = TableOf(handle);
+            const SizeT slot = SlotIndexOf(handle);
+            if (slot >= table.size()) return false;
+            const Latch& latch = table[slot];
+            return latch.RecordLive && latch.RecordGen == handle.Gen;
+        }
+
+        // The memo's other half, and the bound-mirror clearing beside it.
+        //
+        // THE CALLER IS THE CONTRACT's DEATH HELPER (P4a final review C-2): the death path
+        // reads the contract's latch for the wire delete and then forwards here, before the
+        // slot is freed, so a dead handle no longer reads as published in this memo between
+        // the death and the recycle and the three bound mirrors never name a dead program.
+        // Gen-keyed, so a late notice for a slot already handed out again clears nothing of
+        // the successor's.
+        void NoteRecordDestroyed(MGPipeHandle handle) {
+            if (MGPipeHandleIsNull(handle)) return;
+            Vector<Latch>& table = TableOf(handle);
+            const SizeT slot = SlotIndexOf(handle);
+            if (slot < table.size() && table[slot].RecordGen == handle.Gen) {
+                table[slot] = Latch{};
+            }
+            if (m_boundCso == handle) m_boundCso = kMGPipeNullHandle;
+            if (m_drawCso == handle) m_drawCso = kMGPipeNullHandle;
+            if (m_dispatchCso == handle) m_dispatchCso = kMGPipeNullHandle;
+            if (m_constantsCso == handle) {
+                m_constantsCso = kMGPipeNullHandle;
+                m_constantsVersion = kMGPipeGlobalConstantsNeverUploaded;
+            }
+        }
+
+        // The validate point's FreshlyPrimed arm. MGPipeApplierReset clears DrawProgram,
+        // DispatchProgram and BoundShaderCso - all three are per-context WORKING STATE - so
+        // the three mirrors here go with them, or the first emission after a make-current
+        // would be suppressed as unchanged and the server would draw with the previous
+        // context's program bound.
+        //
+        // The RECORD half stays, and that is the rule rather than an oversight: the applier
+        // keeps its shader-CSO records across a make-current because a program lives in a share
+        // group, and re-publishing one would move its Serial for nothing. The global-constants
+        // key goes with the working state because its record's bytes are per (Cso, Version) and
+        // a fresh server has not been told them.
+        void Reset() {
+            m_boundCso = kMGPipeNullHandle;
+            m_drawCso = kMGPipeNullHandle;
+            m_dispatchCso = kMGPipeNullHandle;
+            m_constantsCso = kMGPipeNullHandle;
+            m_constantsVersion = kMGPipeGlobalConstantsNeverUploaded;
+            // The composite memo's freshness goes with them - and only its freshness. Its
+            // ENTRIES name composites whose frontend objects outlive the context switch, so
+            // releasing them here would emit a delete for a live program.
+            MGPipeCompositeResolverInstance().Reset();
+        }
+
+        void ResetCounters() {
+            m_creates = m_binds = m_drawSets = m_dispatchSets = m_constantSets = 0;
+            m_moduleTruncations = 0;
+        }
+
+        // ---- what a unit case reads ----
+        const MGPProgramDesc& LastProgramDesc() const { return m_lastDesc; }
+        const MGPGlobalConstants& LastGlobalConstants() const { return m_lastConstants; }
+        // THE (Cso, Version) KEY set_global_constants is suppressed against. Exposed so a case
+        // can pin that a re-issued create_shader_state invalidates it - the applier clears the
+        // block on the re-issue (wire W6), so a latch that survived it would never re-send.
+        MGPipeHandle GlobalConstantsCso() const { return m_constantsCso; }
+        Uint32 GlobalConstantsVersion() const { return m_constantsVersion; }
+        // D-J3's counted refusal: programs whose linked snapshot carried more modules than
+        // MGPProgramDesc::Spirv[] can name, and whose tail was therefore dropped.
+        Uint64 TruncatedModuleCount() const { return m_moduleTruncations; }
+        MGPipeHandle BoundCso() const { return m_boundCso; }
+        MGPipeHandle DrawCso() const { return m_drawCso; }
+        MGPipeHandle DispatchCso() const { return m_dispatchCso; }
+        Uint64 CreateCount() const { return m_creates; }
+        Uint64 BindCount() const { return m_binds; }
+        Uint64 DrawProgramSetCount() const { return m_drawSets; }
+        Uint64 DispatchProgramSetCount() const { return m_dispatchSets; }
+        Uint64 GlobalConstantsSetCount() const { return m_constantSets; }
+
+    private:
+        // THE ONE PLACE THE BAND CAN ENTER. An ordinary program's slot comes from the ordinary
+        // allocator door keyed on its lifetime id. CompositeResolver.h widens this to send a
+        // pipeline composite through MGPipeSlotAllocator::AllocateComposite instead, and
+        // nothing else about the emission changes - the server never learns a composite is a
+        // composite.
+        MGPipeHandle AcquireShaderCsoHandle(const ProgramObject& program) {
+            const Uint64 lifetimeId = program.GetLifetimeId();
+            const MGPipeHandle existing = MGPipeSlots().FindByLifetimeId(MGPipeKind::ShaderCso, lifetimeId);
+            if (!MGPipeHandleIsNull(existing)) return existing;
+            // A composite is minted off ITS OWN lifetime id, out of the reserved band, and is
+            // an ordinary ShaderCso handle in every other respect - the same kind, the same
+            // {slot, gen} rules, the same Free, the same death helper. Keying it on its own
+            // lifetime id rather than on the pipeline's signature is what makes ~ProgramObject
+            // able to release it at all, and it is why two pipelines that happen to have the
+            // same signature keep their own composite: sharing one handle between two frontend
+            // objects would let the first one's death free a slot the second still names.
+            return MGPipeProgramIsPipelineComposite(program)
+                       ? MGPipeSlots().AllocateComposite(lifetimeId)
+                       : MGPipeSlots().AllocateFor(MGPipeKind::ShaderCso, lifetimeId);
+        }
+
+        struct Latch {
+            Bool RecordLive = false;
+            Uint32 RecordGen = 0;
+            Uint32 LinkVersion = 0;
+        };
+
+        // TWO TABLES, NOT A WIDER ONE, and it is the allocator's own reason repeated where it
+        // bites a second time: the composite band starts at slot 983040, so folding a composite
+        // into the ordinary slot-indexed vector would allocate ~983k latches - and grow them
+        // again on every future push_back - for a single program pipeline. Both spaces stay
+        // dense against their own high-water mark, which is exactly what the allocator does one
+        // level down.
+        Vector<Latch>& TableOf(MGPipeHandle handle) {
+            return MGPipeIsCompositeShaderSlot(handle.Slot) ? m_compositeLatch : m_latch;
+        }
+        const Vector<Latch>& TableOf(MGPipeHandle handle) const {
+            return MGPipeIsCompositeShaderSlot(handle.Slot) ? m_compositeLatch : m_latch;
+        }
+        static SizeT SlotIndexOf(MGPipeHandle handle) {
+            return MGPipeIsCompositeShaderSlot(handle.Slot)
+                       ? static_cast<SizeT>(handle.Slot - kMGPipeShaderCsoCompositeSlotBase)
+                       : static_cast<SizeT>(handle.Slot);
+        }
+        Latch& LatchFor(MGPipeHandle handle) {
+            Vector<Latch>& table = TableOf(handle);
+            const SizeT slot = SlotIndexOf(handle);
+            if (slot >= table.size()) table.resize(slot + 1);
+            return table[slot];
+        }
+
+        static MGPHandleOnly HandleOnly(MGPipeHandle handle) {
+            MGPHandleOnly only{};
+            only.Handle = handle;
+            only.Kind = static_cast<Uint32>(MGPipeKind::ShaderCso);
+            return only;
+        }
+
+        MGPProgramDesc m_lastDesc{};
+        MGPGlobalConstants m_lastConstants{};
+
+        Vector<Latch> m_latch;
+        Vector<Latch> m_compositeLatch;
+        MGPipeHandle m_boundCso = kMGPipeNullHandle;
+        MGPipeHandle m_drawCso = kMGPipeNullHandle;
+        MGPipeHandle m_dispatchCso = kMGPipeNullHandle;
+        MGPipeHandle m_constantsCso = kMGPipeNullHandle;
+        Uint32 m_constantsVersion = kMGPipeGlobalConstantsNeverUploaded;
+
+        Uint64 m_creates = 0;
+        Uint64 m_binds = 0;
+        Uint64 m_drawSets = 0;
+        Uint64 m_dispatchSets = 0;
+        Uint64 m_constantSets = 0;
+        Uint64 m_moduleTruncations = 0;
+    };
+
+    inline MGPipeProgramEmitter& MGPipeProgramEmitterInstance() {
+        // NEVER DESTROYED, for MGPipeTrackerInstance()' reason; heap-constructed and
+        // intentionally leaked at exit, and it MUST NOT hold a frontend SharedPtr - that is
+        // the exit-order rule, stated over every MGPipe process singleton rather than over the
+        // ones a destructor reaches today.
+        static MGPipeProgramEmitter* emitter = new MGPipeProgramEmitter();
+        return *emitter;
+    }
+} // namespace MobileGL::MG_Pipe
+#endif // MOBILEGL_PIPE_PUSH

MobileGL/MG_Impl/Pipe/ResourceTracker.h

@@ -57,33 +57,16 @@ namespace MobileGL::MG_Pipe {
     // D-A3: BindMask
     // ---------------------------------------------------------------------------------
 
-    // MGPResourceDesc::BindMask's twelve bits, in the order MGPipeTypes.h names them:
-    // VERTEX|INDEX|CONSTANT|SHADER_BUFFER|INDIRECT|SAMPLER|SHADER_IMAGE|RENDER_TARGET|
-    // DEPTH_STENCIL|STREAM_OUTPUT|ATOMIC|ELEMENT_ARRAY.
+    // MGPResourceDesc::BindMask's twelve bits MOVED TO MG_Pipe/MGPipeTypes.h AT P4a, beside
+    // the field, exactly as the note that stood here said they would when a second producer
+    // appeared: P4a's texture family sets kMGPipeBindSampler / kMGPipeBindShaderImage /
+    // kMGPipeBindRenderTarget / kMGPipeBindDepthStencil, the four bits nothing set before.
+    // No alias is written for them because none is possible or needed - both files are
+    // namespace MobileGL::MG_Pipe and this one includes that header, so every spelling below
+    // and in package B's code is unchanged.
     //
-    // They are spelled HERE rather than in MGPipeTypes.h because that header is the contract
-    // package's and the mask has, so far, exactly one producer: this file. The integrator
-    // moves them beside the field when a second producer appears (P4a's texture family).
-    enum MGPipeBindBit : Uint16 {
-        kMGPipeBindNone = 0,
-        kMGPipeBindVertex = 1u << 0,
-        kMGPipeBindIndex = 1u << 1,
-        kMGPipeBindConstant = 1u << 2,
-        kMGPipeBindShaderBuffer = 1u << 3,
-        kMGPipeBindIndirect = 1u << 4,
-        kMGPipeBindSampler = 1u << 5,
-        kMGPipeBindShaderImage = 1u << 6,
-        kMGPipeBindRenderTarget = 1u << 7,
-        kMGPipeBindDepthStencil = 1u << 8,
-        kMGPipeBindStreamOutput = 1u << 9,
-        kMGPipeBindAtomic = 1u << 10,
-        // THE D-B7 SWITCH. With kCapNeedsHostIndexBytes set the server mirrors this
-        // resource's bytes so it can rewrite restart indices and flatten multi-draws
-        // (ARCHITECTURE.md 10.3). Getting it wrong is invisible in monolith and silently
-        // disables both under split, which is why it is set from the same table as every
-        // other bit rather than from a special case at the emission site.
-        kMGPipeBindElementArray = 1u << 11,
-    };
+    // What stays here is the BUFFER half of the mapping, which is this file's own: the
+    // BufferTarget table, its sentinel and its completeness assert.
 
     // A sentinel the table below returns for an enumerator it does not name. It is NOT a
     // legal mask value: every enumerator must be listed, including the ones that map to no
@@ -152,12 +135,12 @@ namespace MobileGL::MG_Pipe {
     // The discriminators MGPResourceDesc / MGPSubData carry for a BUFFER
     // ---------------------------------------------------------------------------------
     //
-    // MGPipeTypes.h documents Target as "Buffer | Tex1D..TexCubeArray | Renderbuffer |
-    // TexBuffer" and StorageKind as "== TextureStorageType", but P3a is buffer-only and the
-    // contract package minted no enum for the first list. Buffer is its leading member and
-    // is therefore 0, which is also what a zero-initialised record already says; the second
-    // is the frontend enum, named rather than open-coded.
-    inline constexpr Uint16 kMGPipeResourceTargetBuffer = 0;
+    // P4a MINTED THE FIRST LIST: MGPipeTypes.h now carries enum MGPipeResourceTarget beside
+    // the field, and kMGPipeResourceTargetBuffer moved there with it - the narrowed
+    // resource_respecify ack predicate lives in that header and has to name the buffer target
+    // explicitly, and it may not reach into MG_Impl to do so. The second discriminator is the
+    // frontend enum, named rather than open-coded, and stays here because only this file
+    // produces it.
     inline constexpr Uint8 kMGPipeResourceStorageKindBuffer =
         static_cast<Uint8>(MobileGL::TextureStorageType::Buffer);
 
@@ -552,8 +535,11 @@ namespace MobileGL::MG_Pipe {
     // The monolith's one resource tracker, beside the state tracker, the CSO cache and the
     // set-hash suppressor.
     inline MGPipeResourceTracker& MGPipeResourceTrackerInstance() {
-        static MGPipeResourceTracker tracker;
-        return tracker;
+        // NEVER DESTROYED, for MGPipeSlots()' reason (SlotAllocator.cpp): ~BufferObject reads
+        // and writes this tracker, and the objects that own the last reference to a
+        // BufferObject outlive every function-local static.
+        static MGPipeResourceTracker* tracker = new MGPipeResourceTracker();
+        return *tracker;
     }
 
     // ---------------------------------------------------------------------------------

MobileGL/MG_Impl/Pipe/SetHashSuppressor.h

@@ -18,7 +18,9 @@
 // them answers it against a shape the backend rediscovered. P2 lands the MECHANISM and ONE
 // real consumer (SetVertexAttribDefaults) so the shape is pinned by a test rather than by a
 // plan; the other six slots exist, are unit-tested, and are wired by the phase that moves
-// the set they name. P3a wires the second, SetVertexBuffers.
+// the set they name. P3a wires the second, SetVertexBuffers. P4a wires SetSamplerViews,
+// BindSamplerStates and SetShaderImages, and APPENDS an eighth slot, SetFramebufferState -
+// which leaves only SetShaderBuffers and SetStreamOutputTargets unwired, both P4b's.
 //
 // A WIRED SLOT PUTS A REQUIREMENT ON ITS HASH, and SetVertexBuffers is where that first
 // bites: the hash has to cover EVERY input the record carries, not only the set. Its
@@ -40,15 +42,28 @@
 
 namespace MobileGL::MG_Pipe {
 
-    // One slot per kVarTail set_* (ARCHITECTURE.md 5.1's call list).
+    // One slot per kVarTail set_* (ARCHITECTURE.md 5.1's call list), PLUS
+    // SetFramebufferState, which is not kVarTail at all: MGPFramebufferState carries a
+    // ContentHash for TWO jobs - the server's render-pass memo key and the client's emission
+    // suppressor - and the second one needs a slot here like any other. The enum is
+    // CLIENT-ONLY and is not a wire opcode, so appending before Count is safe.
     enum class MGPipeSuppressorSlot : Uint32 {
         SetVertexBuffers = 0,     // P3a - wired, and its hash includes BaseInstance
-        SetSamplerViews,          // P3b
-        BindSamplerStates,        // P3b
-        SetShaderImages,          // P4b
+        // P4a - WIRED. The three unit sets' suppressors are not optional and were never a
+        // later phase's: MGPipeTypes.h makes the pattern mandatory for every kVarTail set_*,
+        // because GetTextureBindGeneration() bumps on a REDUNDANT rebind - MC 26.2 rebinds the
+        // same sampler at every texture-unit switch - so an unsuppressed set is a
+        // several-hundred-byte variable-length record per batch, which is the exact regression
+        // the design names. What P3b/P4b owns is the ~175-line BACKEND debounce these replace
+        // (UnitBindingsSnapshot / CaptureUnitBindings / UnitBindingsUnchanged and the two
+        // g_*SyncList tables); P4a wires the carrier, P3b/P4b deletes the backend copy.
+        SetSamplerViews,          // P4a - wired (backend debounce deletion: P3b/P4b)
+        BindSamplerStates,        // P4a - wired (backend debounce deletion: P3b/P4b)
+        SetShaderImages,          // P4a - wired (backend debounce deletion: P3b/P4b)
         SetShaderBuffers,         // P4b
         SetStreamOutputTargets,   // P4b
         SetVertexAttribDefaults,  // P2 - the one consumer that is wired
+        SetFramebufferState,      // P4a - wired
         Count,
     };
 
@@ -86,8 +101,11 @@ namespace MobileGL::MG_Pipe {
 
     // The monolith's one suppressor, beside the tracker and the CSO cache.
     inline MGPipeSetHashSuppressor& MGPipeSetHashSuppressorInstance() {
-        static MGPipeSetHashSuppressor suppressor;
-        return suppressor;
+        // NEVER DESTROYED, for MGPipeTrackerInstance()' reason (MG_Impl/Pipe/Tracker.h): the
+        // rule covers every MGPipe process singleton, not only the ones on today's death
+        // paths.
+        static MGPipeSetHashSuppressor* suppressor = new MGPipeSetHashSuppressor();
+        return *suppressor;
     }
 } // namespace MobileGL::MG_Pipe
 #endif // MOBILEGL_PIPE_PUSH

MobileGL/MG_Impl/Pipe/SlotAllocator.cpp

@@ -35,6 +35,22 @@ namespace MobileGL::MG_Pipe {
         return m_kinds[index < kKindCount ? index : 0];
     }
 
+    MGPipeSlotAllocator::SlotState* MGPipeSlotAllocator::EntryOf(KindState& state, MGPipeKind kind,
+                                                                 Uint32 slot) {
+        if (kind == MGPipeKind::ShaderCso && MGPipeIsCompositeShaderSlot(slot)) {
+            const SizeT index = slot - kMGPipeShaderCsoCompositeSlotBase;
+            if (index >= state.BandSlots.size()) return nullptr;
+            return &state.BandSlots[index];
+        }
+        if (slot >= state.Slots.size()) return nullptr;
+        return &state.Slots[slot];
+    }
+
+    const MGPipeSlotAllocator::SlotState*
+    MGPipeSlotAllocator::EntryOf(const KindState& state, MGPipeKind kind, Uint32 slot) {
+        return EntryOf(const_cast<KindState&>(state), kind, slot);
+    }
+
     MGPipeHandle MGPipeSlotAllocator::Allocate(MGPipeKind kind) {
         KindState& state = StateOf(kind);
         if (state.Slots.empty()) {
@@ -94,14 +110,69 @@ namespace MobileGL::MG_Pipe {
         return handle;
     }
 
+    MGPipeHandle MGPipeSlotAllocator::AllocateComposite(Uint64 lifetimeId) {
+        // P4a, D-H7. The mirror image of Allocate() above, restricted to the band that one
+        // refuses, and kept in a table of its own so both spaces stay DENSE: the band's base
+        // is 983040, and minting one composite into the slot-indexed vector would allocate
+        // ~23 MB of SlotState for a single program pipeline.
+        KindState& state = StateOf(MGPipeKind::ShaderCso);
+
+        Uint32 slot = 0;
+        Bool reused = false;
+        if (!state.BandFreeList.empty()) {
+            slot = state.BandFreeList.back();
+            state.BandFreeList.pop_back();
+            reused = true;
+        }
+
+        if (!reused) {
+            const SizeT next = kMGPipeShaderCsoCompositeSlotBase + state.BandSlots.size();
+            slot = static_cast<Uint32>(next);
+            // The band's own exhaustion assert, mirroring Allocate()'s: a composite that
+            // cannot be minted is a NAMED failure, not a silent fall-through into the ordinary
+            // program slots, which is exactly what reserving a band rather than setting a flag
+            // buys.
+            MOBILEGL_ASSERT(next < kMGPipeShaderCsoSlotLimit,
+                            "the MGPipe ShaderCso COMPOSITE band is exhausted at slot %zu; a "
+                            "program-pipeline composite cannot be minted and must not take an "
+                            "ordinary program's slot",
+                            next);
+            if (next >= kMGPipeShaderCsoSlotLimit) return kMGPipeNullHandle;
+            state.BandSlots.emplace_back();
+        }
+
+        SlotState* entry = EntryOf(state, MGPipeKind::ShaderCso, slot);
+        if (entry == nullptr) return kMGPipeNullHandle;
+        if (entry->EverHandedOut) {
+            MOBILEGL_ASSERT(entry->Gen != ~Uint32{0},
+                            "MGPipe handle generation wrapped on the ShaderCso composite band, "
+                            "slot %u; {slot, gen} is no longer unique",
+                            slot);
+            ++entry->Gen;
+        }
+        entry->EverHandedOut = true;
+        entry->Live = true;
+        entry->LifetimeId = lifetimeId;
+        ++state.LiveCount;
+        // The band's share of LiveCount, so CompositeLiveCount() can answer without a walk.
+        ++state.BandLiveCount;
+        if (lifetimeId != 0) {
+            MOBILEGL_ASSERT(state.ByLifetimeId.find(lifetimeId) == state.ByLifetimeId.end(),
+                            "lifetime id %llu already owns a ShaderCso slot",
+                            static_cast<unsigned long long>(lifetimeId));
+            state.ByLifetimeId[lifetimeId] = slot;
+        }
+        return MGPipeHandle{slot, entry->Gen};
+    }
+
     MGPipeHandle MGPipeSlotAllocator::FindByLifetimeId(MGPipeKind kind, Uint64 lifetimeId) const {
         if (lifetimeId == 0) return kMGPipeNullHandle;
         const KindState& state = StateOf(kind);
         const auto it = state.ByLifetimeId.find(lifetimeId);
         if (it == state.ByLifetimeId.end()) return kMGPipeNullHandle;
-        const Uint32 slot = it->second;
-        if (slot >= state.Slots.size() || !state.Slots[slot].Live) return kMGPipeNullHandle;
-        return MGPipeHandle{slot, state.Slots[slot].Gen};
+        const SlotState* entry = EntryOf(state, kind, it->second);
+        if (entry == nullptr || !entry->Live) return kMGPipeNullHandle;
+        return MGPipeHandle{it->second, entry->Gen};
     }
 
     MGPipeHandle MGPipeSlotAllocator::Acquire(MGPipeKind kind, Uint64 lifetimeId) {
@@ -112,63 +183,98 @@ namespace MobileGL::MG_Pipe {
 
     void MGPipeSlotAllocator::Free(MGPipeKind kind, MGPipeHandle handle) {
         KindState& state = StateOf(kind);
-        if (handle.Slot >= state.Slots.size()) return;
-        SlotState& entry = state.Slots[handle.Slot];
+        SlotState* entry = EntryOf(state, kind, handle.Slot);
+        if (entry == nullptr) return;
         // A stale handle must not free the slot its successor now owns - that is the whole
-        // reason the generation is in the key.
-        if (!entry.Live || entry.Gen != handle.Gen) return;
-        if (entry.LifetimeId != 0) {
-            const auto it = state.ByLifetimeId.find(entry.LifetimeId);
+        // reason the generation is in the key. It is also what makes the SECOND of a
+        // composite's two independent release paths a proven no-op.
+        if (!entry->Live || entry->Gen != handle.Gen) return;
+        if (entry->LifetimeId != 0) {
+            const auto it = state.ByLifetimeId.find(entry->LifetimeId);
             if (it != state.ByLifetimeId.end() && it->second == handle.Slot) {
                 state.ByLifetimeId.erase(it);
             }
         }
-        entry.Live = false;
-        entry.LifetimeId = 0;
+        entry->Live = false;
+        entry->LifetimeId = 0;
         --state.LiveCount;
+        if (kind == MGPipeKind::ShaderCso && MGPipeIsCompositeShaderSlot(handle.Slot)) {
+            --state.BandLiveCount;
+            state.BandFreeList.push_back(handle.Slot);
+        } else {
             state.FreeList.push_back(handle.Slot);
         }
+    }
 
     Bool MGPipeSlotAllocator::IsLive(MGPipeKind kind, MGPipeHandle handle) const {
-        const KindState& state = StateOf(kind);
-        if (handle.Slot >= state.Slots.size()) return false;
-        const SlotState& entry = state.Slots[handle.Slot];
-        return entry.Live && entry.Gen == handle.Gen;
+        const SlotState* entry = EntryOf(StateOf(kind), kind, handle.Slot);
+        return entry != nullptr && entry->Live && entry->Gen == handle.Gen;
     }
 
     Uint32 MGPipeSlotAllocator::GenOfSlot(MGPipeKind kind, Uint32 slot) const {
-        const KindState& state = StateOf(kind);
-        if (slot >= state.Slots.size()) return 0;
-        return state.Slots[slot].Gen;
+        const SlotState* entry = EntryOf(StateOf(kind), kind, slot);
+        return entry != nullptr ? entry->Gen : 0;
     }
 
     Uint64 MGPipeSlotAllocator::LifetimeIdOfSlot(MGPipeKind kind, Uint32 slot) const {
-        const KindState& state = StateOf(kind);
-        if (slot >= state.Slots.size()) return 0;
-        return state.Slots[slot].LifetimeId;
+        const SlotState* entry = EntryOf(StateOf(kind), kind, slot);
+        return entry != nullptr ? entry->LifetimeId : 0;
     }
 
     Uint32 MGPipeSlotAllocator::HighWater(MGPipeKind kind) const {
+        // THE ORDINARY SPACE ONLY, and the band is reported by CompositeHighWater() below.
+        // Folding the two would pin this at ~983k from the first composite mint onward and
+        // take the ordinary space's "the high-water mark did not move" assertion away for the
+        // rest of the process - the assertion that catches a dense table that never shrinks,
+        // which is the leak shape this allocator exists to make visible. Two spaces, two
+        // numbers, two real assertions. See SlotAllocator.h.
         return static_cast<Uint32>(StateOf(kind).Slots.size());
     }
 
+    Uint32 MGPipeSlotAllocator::CompositeHighWater() const {
+        const KindState& state = StateOf(MGPipeKind::ShaderCso);
+        // One past the highest composite slot ever handed out; exactly the base when none ever
+        // was, so the number is monotone from the first mint and a LEAKED COMPOSITE MOVES IT.
+        return static_cast<Uint32>(kMGPipeShaderCsoCompositeSlotBase + state.BandSlots.size());
+    }
+
     Uint32 MGPipeSlotAllocator::LiveCount(MGPipeKind kind) const { return StateOf(kind).LiveCount; }
 
+    Uint32 MGPipeSlotAllocator::CompositeLiveCount() const {
+        return StateOf(MGPipeKind::ShaderCso).BandLiveCount;
+    }
+
     Uint32 MGPipeSlotAllocator::FreeCount(MGPipeKind kind) const {
-        return static_cast<Uint32>(StateOf(kind).FreeList.size());
+        const KindState& state = StateOf(kind);
+        return static_cast<Uint32>(state.FreeList.size() + state.BandFreeList.size());
+    }
+
+    Uint32 MGPipeSlotAllocator::CompositeFreeCount() const {
+        return static_cast<Uint32>(StateOf(MGPipeKind::ShaderCso).BandFreeList.size());
     }
 
     void MGPipeSlotAllocator::Reset() {
         for (KindState& state : m_kinds) {
             state.Slots.clear();
             state.FreeList.clear();
+            state.BandSlots.clear();
+            state.BandFreeList.clear();
             state.ByLifetimeId.clear();
             state.LiveCount = 0;
+            state.BandLiveCount = 0;
         }
     }
 
     MGPipeSlotAllocator& MGPipeSlots() {
-        static MGPipeSlotAllocator allocator;
-        return allocator;
+        // NEVER DESTROYED, deliberately (one allocation for the life of the process). A
+        // frontend object's destructor reaches this allocator - ~BufferObject through
+        // MGPipeEmitResourceDestroyAndFree, ~VertexArrayObject through the death notice - and
+        // MG_Backend/MGPipe/PipeInputs.h's gPipeInputs holds SharedPtrs to those objects at
+        // namespace scope, so they are destroyed by __run_exit_handlers AFTER this
+        // function-local static would have been. A destroyed allocator then answers
+        // FindByLifetimeId out of a freed hash table and Free() writes into freed vectors -
+        // an exit-time heap corruption whose fatality depends only on the allocator's layout.
+        static MGPipeSlotAllocator* allocator = new MGPipeSlotAllocator();
+        return *allocator;
     }
 } // namespace MobileGL::MG_Pipe

MobileGL/MG_Impl/Pipe/SlotAllocator.h

@@ -47,6 +47,25 @@ namespace MobileGL::MG_Pipe {
         MGPipeHandle Allocate(MGPipeKind kind);
         // Allocate and remember `lifetimeId` as this handle's frontend identity.
         MGPipeHandle AllocateFor(MGPipeKind kind, Uint64 lifetimeId);
+
+        // P4a, D-H7: THE ONE ENTRY POINT INTO THE ShaderCso COMPOSITE BAND, and the only one
+        // there will ever be. Allocate() above refuses that band on purpose, so a program
+        // pipeline's flattened composite - minted client-side from the stage programs bound to
+        // the pipeline object, and indistinguishable from an ordinary program to the server -
+        // needs a door of its own rather than a flag on the handle. The kind is implied: only
+        // ShaderCso has a band.
+        //
+        // It behaves exactly like AllocateFor in every other respect (free list first, then
+        // the band's own high-water mark; Gen moves only on reuse; the lifetimeId -> slot map
+        // is written) and it carries the band's own exhaustion assert, so exhausting the
+        // composite space is a NAMED Fatal rather than silent slot theft from ordinary
+        // programs. Returns kMGPipeNullHandle when the band is full.
+        //
+        // Freed through the ordinary Free(MGPipeKind::ShaderCso, handle): a composite's slot
+        // has two independent release paths - the pipeline cache's LRU eviction and the
+        // composite ProgramObject's own destructor - and Free refusing a slot that is not live
+        // at that generation is what makes the second one a proven no-op.
+        MGPipeHandle AllocateComposite(Uint64 lifetimeId);
         // The handle a lifetime id was allocated for, or kMGPipeNullHandle. A recycled heap
         // address does NOT reproduce a mapping: MG_State hands out a fresh lifetime id per
         // object, so the map key is unique for the life of the process.
@@ -64,11 +83,40 @@ namespace MobileGL::MG_Pipe {
         // otherwise, live or not.
         Uint32 GenOfSlot(MGPipeKind kind, Uint32 slot) const;
         Uint64 LifetimeIdOfSlot(MGPipeKind kind, Uint32 slot) const;
-        // One past the highest slot ever handed out of this kind, i.e. what a server-side
-        // slot-indexed table must be sized to.
+        // One past the highest ORDINARY slot ever handed out of this kind. For every kind but
+        // ShaderCso that is the whole story; for ShaderCso the composite band is a second,
+        // separately dense space and CompositeHighWater() below answers it.
+        //
+        // THE TWO SPACES ARE REPORTED SEPARATELY, and that is the point rather than a detail.
+        // Folding the band into this number pins it at ~983k from the first composite mint
+        // onward, and every later assertion of the "the high-water mark did not move over N
+        // churn rounds" shape - the one that catches a dense table that never shrinks, which
+        // is the ~1.3 KB-per-record leak C-1 produced - becomes vacuously true for ordinary
+        // ShaderCso slots for the rest of the process. A leak case per space is two real
+        // assertions; one merged number is one real assertion and one that cannot go red.
+        //
+        // It is also NOT a table size for kind ShaderCso even now: the band is sparse against
+        // the ordinary space by design, so a consumer indexing by slot must test
+        // MGPipeIsCompositeShaderSlot(slot) first and keep the band in a table of its own,
+        // exactly as this allocator does.
         Uint32 HighWater(MGPipeKind kind) const;
+        // One past the highest COMPOSITE slot ever handed out, i.e.
+        // kMGPipeShaderCsoCompositeSlotBase + (band slots ever handed out), and exactly the
+        // base when none ever was. Kind ShaderCso is the only kind with a band, so it is
+        // implied - as it is for AllocateComposite. A LEAKED COMPOSITE MOVES THIS and moves
+        // nothing else, which is what the composite's own leak case asserts on.
+        Uint32 CompositeHighWater() const;
+        // Live slots of this kind, ORDINARY AND COMPOSITE TOGETHER for ShaderCso: a live
+        // composite is a live ShaderCso, the applier's two record tables are one object class,
+        // and a caller asking "how many shader CSOs does this client hold" wants both. The
+        // band's own count is CompositeLiveCount(); the ordinary space's is the difference.
         Uint32 LiveCount(MGPipeKind kind) const;
+        Uint32 CompositeLiveCount() const;
+        // Slots waiting on a free list. Also BOTH SPACES for ShaderCso, for LiveCount's
+        // reason and with the same caveat: a caller that needs to know WHICH space a slot went
+        // back to reads CompositeFreeCount() and subtracts.
         Uint32 FreeCount(MGPipeKind kind) const;
+        Uint32 CompositeFreeCount() const;
 
         // Context teardown / server reset / a unit test's fixture.
         void Reset();
@@ -85,12 +133,30 @@ namespace MobileGL::MG_Pipe {
             // Indexed by slot; [0] is the reserved slot and is never live.
             Vector<SlotState> Slots;
             Vector<Uint32> FreeList;
+            // P4a: the ShaderCso COMPOSITE band, indexed by (slot - the band's base) and
+            // EMPTY for every other kind. A SECOND VECTOR RATHER THAN MORE OF THE FIRST, and
+            // it is not a micro-optimisation: the band starts at 983040, so minting one
+            // composite into the slot-indexed vector above would allocate ~983k SlotStates -
+            // ~23 MB - for a single program pipeline, and a consumer that sized a table off
+            // HighWater would pay the same shape again with a far bigger record. Both spaces
+            // stay dense against their own high-water mark, which is the property this
+            // allocator exists to give the server.
+            Vector<SlotState> BandSlots;
+            Vector<Uint32> BandFreeList;
             UnorderedMap<Uint64, Uint32> ByLifetimeId;
             Uint32 LiveCount = 0;
+            // The band's share of LiveCount above, so the two spaces can be reported apart
+            // without walking either table. Always 0 for every kind but ShaderCso.
+            Uint32 BandLiveCount = 0;
         };
 
         KindState& StateOf(MGPipeKind kind);
         const KindState& StateOf(MGPipeKind kind) const;
+        // The SlotState a (kind, slot) names, in whichever of the two vectors holds it, or
+        // null when the slot has never been handed out. One resolver, so a caller that forgets
+        // the band cannot exist.
+        static SlotState* EntryOf(KindState& state, MGPipeKind kind, Uint32 slot);
+        static const SlotState* EntryOf(const KindState& state, MGPipeKind kind, Uint32 slot);
 
         Array<KindState, kKindCount> m_kinds{};
     };

MobileGL/MG_Impl/Pipe/Tracker.h

@@ -20,9 +20,24 @@
 //
 // WHAT IT DOES. One Uint32 dirty mask per verb, one bit per row of ARCHITECTURE.md 5.2,
 // computed by comparing a shutter against what the tracker last pushed. P2 emitted for bits
-// 0..4 (the value-class ones); P3a adds bits 5, 9 and 10 - the vertex-input family - and the
-// rest are still computed, latched and counted so the per-bit fire rate is a measurement
-// rather than a plan, with their fields going through the residual fill until P3b/P4a/P4b.
+// 0..4 (the value-class ones); P3a adds bits 5, 9 and 10 - the vertex-input family - and P4a
+// adds SEVEN: 6, 7 and 8 (the program family), 11 (the framebuffer) and 12, 13 and 14 (the
+// three unit sets). Only bits 15, 16 and 17 - the const-buffer, shader-buffer and
+// stream-output sets - are still computed, latched and counted without an emitter, so the
+// per-bit fire rate is a measurement rather than a plan and their fields go through the
+// residual fill until P4b.
+//
+// P4a NARROWS NOTHING AND WIDENS THREE THINGS, and every one of them was an UNDER-FIRE that
+// only became reachable once the bit gained an emitter:
+//   (1) bit 11's shutter gains the READ framebuffer binding slot's version, because
+//       set_framebuffer_state is emitted per bound TARGET and a glBindFramebuffer(
+//       GL_READ_FRAMEBUFFER, ...) moved no shutter at all before;
+//   (2) bit 13's gains the TEXTURE BIND generation, because glBindSampler moves that one and
+//       not the sampling-resolution one, so bind_sampler_states could not see a sampler bind;
+//   (3) bits 6/7/8 - and with them bit 14's program half - read the EFFECTIVE program source
+//       instead of GetCurrentProgram() alone, which is null for the whole life of a bound
+//       separable program pipeline, so a re-composited pipeline reached no program emitter.
+// Over-firing is free; all three of those were the other direction.
 //
 // WHY EVERY SHUTTER OVER-FIRES. A bit that fires too often costs one extra push. A bit
 // that fires too rarely renders stale, and ARCHITECTURE.md 13.2 names that as the
@@ -61,22 +76,24 @@ namespace MobileGL::MG_Pipe {
         NewPixelPack,            // PixelStoreParameters (pack)         -> set_pixel_pack_state
         NewPatchState,           // the patch trio, NaN legal           -> set_patch_state
         NewVertexAttribDefaults, // glVertexAttrib* defaults            -> set_vertex_attrib_defaults
-        // ---- value class: NEW_VERTEX_ELEMENTS is emitted from P3a; the other three are
-        // still computed and counted, and are emitted from P3b/P4a on ----
+        // ---- value class: NEW_VERTEX_ELEMENTS is emitted from P3a and the other three from
+        // P4a - the program family, one subsystem, three bits because the frontend moves them
+        // as three separate events ----
         NewVertexElements,       // the bound VAO's attribute configuration -> create/bind_vertex_elements
-        NewShader,               // the current program's link version
-        NewShaderBindings,       // image units, block bindings, uniform write set
-        NewGlobalConstants,      // the default-uniform-block image
+        NewShader,               // the current program's link version -> create/bind_shader_state,
+                                 //    set_draw_program, set_dispatch_program (P4a)
+        NewShaderBindings,       // image units, block bindings, uniform write set (P4a)
+        NewGlobalConstants,      // the default-uniform-block image -> set_global_constants (P4a)
         // ---- object class. THE FIRST TWO ARE P3a's, not P3b/P4b's: the roadmap puts
         // set_vertex_buffers and set_index_buffer in the same phase as the vertex-elements
-        // trio, and this comment said otherwise until the commit that wired them. The rest
-        // are still computed and counted only. ----
+        // trio, and this comment said otherwise until the commit that wired them. THE NEXT
+        // FOUR ARE P4a's. The last three are still computed and counted only, until P4b. ----
         NewVertexBuffers,        // -> set_vertex_buffers (P3a)
         NewIndexBuffer,          // -> set_index_buffer   (P3a)
-        NewFramebuffer,
-        NewSamplerViews,
-        NewSamplers,
-        NewShaderImages,
+        NewFramebuffer,          // -> set_framebuffer_state, per bound target (P4a)
+        NewSamplerViews,         // -> set_sampler_views   (P4a)
+        NewSamplers,             // -> bind_sampler_states (P4a)
+        NewShaderImages,         // -> set_shader_images   (P4a)
         NewConstBuffers,
         NewShaderBuffers,
         NewSoTargets,
@@ -103,6 +120,22 @@ namespace MobileGL::MG_Pipe {
         kMGPipeDirtyEmittedAtP2 | MGPipeDirtyBit(MGPipeDirty::NewVertexElements) |
         MGPipeDirtyBit(MGPipeDirty::NewVertexBuffers) | MGPipeDirtyBit(MGPipeDirty::NewIndexBuffer);
 
+    // The SEVEN P4a adds, across FOUR subsystems: bits 6/7/8 are the program family, 11 the
+    // framebuffer, and 12/13/14 the sampler-view / sampler-state / image-unit sets. Added
+    // rather than edited into the two above, for the reason those two exist: each phase's
+    // constant survives as the next phase's A/B control and as what a test compares the
+    // subsystem map against.
+    //
+    // EVERY ONE OF THESE SHUTTERS WAS ALREADY COMPUTED, LATCHED AND COUNTED before P4a; what
+    // P4a adds is an emitter for them. That is why this is a one-line constant and not seven
+    // new shutters - and it is also why the two narrowings below are stated as requirements.
+    inline constexpr Uint32 kMGPipeDirtyEmittedAtP4a =
+        kMGPipeDirtyEmittedAtP3a | MGPipeDirtyBit(MGPipeDirty::NewShader) |
+        MGPipeDirtyBit(MGPipeDirty::NewShaderBindings) |
+        MGPipeDirtyBit(MGPipeDirty::NewGlobalConstants) |
+        MGPipeDirtyBit(MGPipeDirty::NewFramebuffer) | MGPipeDirtyBit(MGPipeDirty::NewSamplerViews) |
+        MGPipeDirtyBit(MGPipeDirty::NewSamplers) | MGPipeDirtyBit(MGPipeDirty::NewShaderImages);
+
     inline constexpr const char* kMGPipeDirtyNames[kMGPipeDirtyCount] = {
         "NEW_RENDER_STATE",
         "NEW_PIPELINE_STATE",
@@ -146,8 +179,33 @@ namespace MobileGL::MG_Pipe {
         case MGPipeDirty::NewVertexBuffers:
         case MGPipeDirty::NewIndexBuffer:
             return kMGPipeSubsystemVertexInput;
+        // P4a's seven, across four subsystems. FOUR AND NOT ONE for P3a's reason one level
+        // out: a framebuffer path that regressed, a texture path that regressed, a sampler
+        // path that regressed and a program path that regressed are four different findings.
+        //
+        // The program family is three bits because the frontend moves them separately - a
+        // relink, a binding change and a uniform write are three events - but one subsystem,
+        // because an operator switching programs off has to get the whole family's legacy arm.
+        // Same for the three unit sets: create_sampler_state, create_sampler_view and the
+        // three kVarTail sets are one family, and half of it is not a control.
+        case MGPipeDirty::NewShader:
+        case MGPipeDirty::NewShaderBindings:
+        case MGPipeDirty::NewGlobalConstants:
+            return kMGPipeSubsystemPrograms;
+        case MGPipeDirty::NewFramebuffer:
+            return kMGPipeSubsystemFramebuffer;
+        case MGPipeDirty::NewSamplerViews:
+        case MGPipeDirty::NewSamplers:
+        case MGPipeDirty::NewShaderImages:
+            return kMGPipeSubsystemSamplers;
+        // NO BIT NAMES kMGPipeSubsystemTextureResources, and that is deliberate rather than an
+        // omission: the texture and renderbuffer resource_* calls and set_texture_params are
+        // dispatched from the GL entry points that cause them - a constructor, a storage
+        // definition, a glTexParameter - not from a dirty walk, exactly as P3a's buffer family
+        // is. Bit 10 gates those dispatch sites; there is no dirty bit to map onto it and
+        // there must not be one, or the emission would be gated twice and disagree with itself.
         default:
-            // The remaining bits have no call of their own until P3b/P4a/P4b, so there is no
+            // The remaining bits have no call of their own until P4b, so there is no
             // subsystem to switch and the residual fill keeps supplying their fields.
             return 0;
         }
@@ -243,11 +301,66 @@ namespace MobileGL::MG_Pipe {
             // must not force a compile just to answer "did the shader move". These version
             // counters are plain members and are exactly what the backends already read
             // without joining (Core.cpp, the glUseProgram half of join site J1).
+            //
+            // BUT GetCurrentProgram() ALONE IS NOT THE PROGRAM SOURCE, AND AT P4a THAT IS AN
+            // UNDER-FIRE. Under GL_ARB_separate_shader_objects an application drives
+            // `glUseProgram(0); glBindProgramPipeline(P)`, and m_currentProgram is then null
+            // for the whole life of that pipeline (Core.cpp, GetProgramForDraw's second half):
+            // all three of these shutters read 0 == 0 forever, so after the first walk on a
+            // fresh context - the one !m_primed fires unconditionally - bits 6, 7 and 8 never
+            // fire again however the pipeline is restaged.
+            //
+            // WHILE NOTHING WAS EMITTED FOR THEM THAT WAS INVISIBLE, which is how it survived
+            // to P4a: GetProgramForDraw is emitted-and-still-pulled, the residual fill copies
+            // it at every verb, and DirtySurface.def rules BindProgramPipelineObject
+            // kPulledEveryVerb for exactly that reason - the backend still receives the right
+            // SharedPtr and nothing renders wrong. The moment P4a emits off these bits it
+            // stops being invisible: glUseProgramStages rebuilds the composite, EmitShaderState
+            // is never called again, so the new composite gets no ShaderCso handle and no
+            // create_shader_state while set_draw_program keeps naming the previous one - a
+            // program the handle protocol never announced, which is exactly the seam-defect
+            // class P3a spent a phase closing. And bit 8 never firing means
+            // set_global_constants is never sent for a pipeline draw at all, where the pull
+            // rescues nothing.
+            //
+            // SO THE SHUTTER READS THE EFFECTIVE SOURCE: the program in use when there is one,
+            // and the bound pipeline when there is not. What it reads OF that pipeline is the
+            // pair ComputeDrawProgramSignature() is built from - each stage program's lifetime
+            // id and LINK version - so bit 6 fires exactly when GetProgramForDraw would hand
+            // back a different composite, which is exactly when a new ShaderCso handle has to
+            // be minted. Those are the same non-artefact fields the plain-program arm above
+            // reads, and the ones Core.cpp calls out as not passing through ProgramObject's
+            // join gate, so the "must not force a compile" rule survives intact: no join, no
+            // flatten, no Link().
+            //
+            // THE PIPELINE NAME IS MIXED IN because two pipelines can carry the same stage set
+            // and each caches its OWN composite object, so the signature alone would let a
+            // glBindProgramPipeline between two such pipelines pass without a fire. What that
+            // does NOT close is a name RECYCLED (glDeleteProgramPipelines +
+            // glGenProgramPipelines) back onto the same stage programs at the same link
+            // versions with no other program-family change in between: a ProgramPipelineObject
+            // has no lifetime id and no wire object at all - DirtySurface.def says so where it
+            // rules MarkProgramPipelineForDeletion kUnpublishedDestroy - so there is nothing
+            // else here to mix it with. Recorded rather than quietly left: closing it needs a
+            // generation counter on the frontend object, which is an MG_State change and not
+            // this file's to make.
             const auto& program = ctx.GetCurrentProgram();
             Uint64 shader = 0;
             Uint64 bindings = 0;
             Uint64 constants = 0;
             Uint64 programImages = 0;
+            // THE PROGRAM INPUT OF THE PROGRAM-RESOLVED VIEW SET (P4a fable seam F-1).
+            // set_sampler_views is resolved for the program in use (SamplerEmit.h: the sampler
+            // uniform's TYPE picks which of a unit's targets is the view) and the emitter
+            // memoises that resolution on (lifetime id, link version, backend state version). A
+            // shutter that read only the texture generations therefore missed a glUseProgram:
+            // `glBindTexture x N; glUseProgram(P1); draw; glUseProgram(P2); draw` moved nothing
+            // bit 12 read, so the view set stayed P1's - and E's record epoch, keyed on the two
+            // set serials, then never rebuilt the texture sync list for P2 either. This value is
+            // that memo key, and bit 12 mixes it in below: over-firing costs one re-resolution
+            // the set-hash suppressor absorbs, under-firing left the record describing the
+            // previous program's units.
+            Uint64 opaqueUnits = 0;
             if (program) {
                 shader = MGPipeMixShutter(program->GetLifetimeId(), program->GetLinkVersion());
                 bindings = MGPipeMixShutter(
@@ -256,12 +369,156 @@ namespace MobileGL::MG_Pipe {
                                      program->GetBlockBindingVersion()),
                     program->GetUniformWriteSetVersion());
                 constants = MGPipeMixShutter(program->GetLifetimeId(), program->GetUBOContentVersion());
-                programImages = program->GetImageUnitVersion();
+                // THE IDENTITY IS MIXED IN (P4a fable seam F-2), exactly as the pipeline arm
+                // below mixes stageLinks into its half: the counter alone is a per-program
+                // number two programs routinely share - 0 == 0 for any pair that never moved an
+                // image unit through glUniform1i, and 0 == 0 against no program at all - so a
+                // glUseProgram between them fired nothing, set_shader_images' window stayed the
+                // previous program's, and a program whose only image is a BUFFER image (E's
+                // SD-4: nothing else moves between the bind and the dispatch) never reached the
+                // record at all.
+                programImages = MGPipeMixShutter(shader, program->GetImageUnitVersion());
+                opaqueUnits = MGPipeMixShutter(shader, program->GetBackendStateVersion());
+            } else if (const auto& pipeline = ctx.GetBoundProgramPipeline(); pipeline) {
+                using Pipeline = MG_State::GLState::ProgramPipelineObject;
+                // THE FIELDS ARE READ DIRECTLY RATHER THAN THROUGH THE TWO FUNCTIONS THAT
+                // ALREADY PACK THEM, and that is a gate constraint, not a preference. Calling
+                // ComputeDrawProgramSignature() / ComputeUniformMirrorVersions() would say
+                // "the same pairs the composite cache and the uniform-mirror gate compare"
+                // far better than this loop does - but gen_pipe_dirty_surface.py derives a
+                // shutter by following each accessor to the member it returns, and both of
+                // those build a LOCAL array and return that, which it cannot place. A shutter
+                // naming them is UNRESOLVED, and then every DirtySurface.def row that names
+                // bits 6, 7, 8 or 14 loses its verdict - including the derivation that is the
+                // only mechanism able to catch the next under-fire here. So the pairs are
+                // spelled out, and the two static_asserts below are what say they must stay in
+                // step with the functions they mirror.
+                static_assert(sizeof(Pipeline::DrawProgramSignature) ==
+                                  2 * Pipeline::kGraphicsStageCount * sizeof(Uint64),
+                              "bit 6 reads the {lifetimeId, linkVersion} pair per graphics "
+                              "stage that ComputeDrawProgramSignature packs");
+                static_assert(sizeof(Pipeline::UniformMirrorVersions) ==
+                                  2 * Pipeline::kGraphicsStageCount * sizeof(Uint64),
+                              "bits 7 and 8 read the four counters per graphics stage that "
+                              "ComputeUniformMirrorVersions packs");
+
+                // Bit 6 is the pipeline's identity plus the composite cache key. Bits 7 and 8
+                // add the per-program state, which under a pipeline is written to the STAGE
+                // programs - glUniform* addresses the pipeline's active program,
+                // glProgramUniform* and the two block-binding calls address a named one - and
+                // only reaches the composite through RefreshCompositeUniforms. Bit 14's half
+                // takes the image-unit generation, which is its own counter for the reason
+                // ProgramObject gives (ES forbids glUniform1i on an image uniform, so Espryt
+                // BAKES the unit into the ESSL it generates and only a regeneration honours a
+                // change) and which D-G4 asks this shutter to keep reading as a FRONTEND
+                // counter rather than any server-side epoch.
+                //
+                // STAGELINKS IS MIXED INTO ALL THREE OF THE OTHERS, ON PURPOSE. A composite
+                // REBUILD hands back a brand-new ProgramObject with an empty default uniform
+                // block and no backend state at all - SetCachedDrawProgram clears the mirror
+                // versions with it - so a shutter watching only the per-stage state counters
+                // would let a rebuilt composite inherit the bindings, the constants and the
+                // image units of the one it replaced.
+                Uint64 stageLinks = static_cast<Uint64>(ctx.GetBoundProgramPipelineName());
+                Uint64 stageState = 0;
+                Uint64 stageImages = 0;
+                // The per-stage sampler/image unit assignments alone (glUniform1i on a stage
+                // program's sampler moves its backend state version and reaches the composite
+                // through the uniform mirror), for bit 12's program input below.
+                Uint64 stageOpaque = 0;
+                for (SizeT stage = 0; stage < Pipeline::kGraphicsStageCount; ++stage) {
+                    const auto& staged = pipeline->GetStageProgram(static_cast<ShaderStage>(stage));
+                    if (!staged) continue;
+                    stageLinks = MGPipeMixShutter(
+                        MGPipeMixShutter(stageLinks, staged->GetLifetimeId()), staged->GetLinkVersion());
+                    stageState = MGPipeMixShutter(
+                        MGPipeMixShutter(MGPipeMixShutter(stageState, staged->GetBackendStateVersion()),
+                                         MGPipeMixShutter(staged->GetUBOContentVersion(),
+                                                          staged->GetBlockBindingVersion())),
+                        staged->GetUniformWriteSetVersion());
+                    stageImages = MGPipeMixShutter(stageImages, staged->GetImageUnitVersion());
+                    stageOpaque = MGPipeMixShutter(stageOpaque, staged->GetBackendStateVersion());
+                }
+                shader = stageLinks;
+                stageState = MGPipeMixShutter(stageLinks, stageState);
+                bindings = MGPipeMixShutter(stageState, stageImages);
+                constants = stageState;
+                programImages = MGPipeMixShutter(stageLinks, stageImages);
+                opaqueUnits = MGPipeMixShutter(stageLinks, stageOpaque);
             }
             now[Index(MGPipeDirty::NewShader)] = shader;
             now[Index(MGPipeDirty::NewShaderBindings)] = bindings;
             now[Index(MGPipeDirty::NewGlobalConstants)] = constants;
 
+            // ===========================================================================
+            // THE RECORD-FIELD -> SETTER -> SHUTTER TABLE FOR THE SEVEN P4a BITS.
+            //
+            // THE RULE (P4a fable seam audit, section C.1): every field of every emitted
+            // record names the frontend setter that changes it, and that setter moves a
+            // counter the emitting bit's shutter reads - or the emission is unconditional at
+            // the setter (the resource_* family, set_texture_params). A record field whose
+            // setter moves no shutter input is a stale record with nothing to refuse: c0d
+            // (bit 13 without the bind generation), SD-0 (an image re-bind), F-1 (the
+            // program behind the view set), F-2 (the program behind the image window) and
+            // F-3 (an attached object's storage) were all this one class. DirtySurface.def
+            // cannot catch it - it maps MUTATORS to bits and cannot see that a DERIVED field
+            // depends on a mutator whose row is another family's - so the table lives here,
+            // beside the shutters, and a row is added whenever a record gains a field.
+            //
+            // bit 6  create/bind_shader_state, set_draw/dispatch_program (ProgramEmit.h)
+            //        fields: Cso, StageMask, GlobalUboSize, the artefact blob refs, the two
+            //                bound handles
+            //        setters: glUseProgram (m_currentProgram), glLinkProgram (link version),
+            //                glBindProgramPipeline / glUseProgramStages (pipeline name +
+            //                per-stage {lifetime id, link version})
+            //        shutter: lifetime id x link version, or stageLinks under a pipeline
+            // bit 7  the program's bindings (image units, block bindings, uniform write set)
+            //        setters: glUniform1i on an opaque uniform (backend state version, image
+            //                unit version), glUniformBlockBinding / glShaderStorageBlockBinding
+            //                (block binding version), any glUniform* (uniform write set)
+            //        shutter: the four per-program counters, x stageLinks under a pipeline
+            // bit 8  set_global_constants: ShaderCso, Version, the default-block image
+            //        setters: any glUniform* on the default block (UBO content version),
+            //                glUseProgram (lifetime id)
+            //        shutter: lifetime id x UBO content version, or stageState
+            // bit 11 set_framebuffer_state: Fbo, Color[8]/Depth/Stencil/ReadSurface
+            //        (Res, Kind, InternalFormat, TextureTarget, Layered, Level, Layer,
+            //        UploadTarget), DrawBuffers[8], Width/Height/Layers/Samples/
+            //        FixedSampleLocations, IsDefault, Complete, Target
+            //        setters: glFramebufferTexture*/glFramebufferRenderbuffer, glDrawBuffer(s),
+            //                glReadBuffer, glFramebufferParameteri (the attachment
+            //                aggregate); glBindFramebuffer (the two binding slot versions);
+            //                AND a storage redefinition of an ATTACHED texture or
+            //                renderbuffer - glTexImage*/glTexStorage*/glTexBuffer/
+            //                glTextureView/glRenderbufferStorage* - because InternalFormat,
+            //                TextureTarget, the extent, Samples and Complete are INLINED at
+            //                emission (D-C1): those bump the attachment aggregate from the
+            //                object's PipePublishDescriptor (F-3)
+            //        shutter: attachment aggregate x draw bind version x read bind version
+            // bit 12 set_sampler_views: per unit {View, Texture}
+            //        setters: glBindTexture / glActiveTexture (bind generation), a texture's
+            //                or a sampler object's parameters (SamplesAsIncompleteTexture -
+            //                the params aggregate), an upload that defines a level (content
+            //                aggregate), the default texture's image appearing (bind
+            //                generation, TextureObject.cpp); AND the program in use -
+            //                glUseProgram, a relink, glUniform1i on a sampler uniform (which
+            //                unit a uniform's TYPE resolves) - F-1
+            //        shutter: content x params x bind generation x opaqueUnits
+            // bit 13 bind_sampler_states: per unit the sampler CSO handle
+            //        setters: glBindSampler (bind generation, c0d), glSamplerParameter* /
+            //                glTexParameter* (params aggregate + sampling resolution),
+            //                glDeleteSamplers (bind generation)
+            //        shutter: params x sampling resolution x bind generation
+            // bit 14 set_shader_images: per unit {Res, InternalFormat, Layer, Level,
+            //        Layered, Access} over the program's image-unit window
+            //        setters: glBindImageTexture (bind generation, SD-0), a texture's
+            //                content/params, glUniform1i on an image uniform (image unit
+            //                version); AND the program in use - glUseProgram, a relink -
+            //                F-2
+            //        shutter: content x params x bind generation x programImages
+            //                (lifetime id x link version x image unit version)
+            // ===========================================================================
+
             // ---- the object-class bits 9..17 ----
             const Uint64 textureContent = ctx.GetAnyTextureContentGeneration();
             const Uint64 textureParams = ctx.GetAnyTextureParamsGeneration();
@@ -300,16 +557,82 @@ namespace MobileGL::MG_Pipe {
                                                 indexObject ? indexObject->GetLifetimeId() : 0);
             }
             now[Index(MGPipeDirty::NewIndexBuffer)] = MGPipeMixShutter(vaoIdentity, indexShutter);
+            // Bit 11, WIDENED AT P4a AND THIS IS A REQUIREMENT RATHER THAN AN OPTION. The
+            // shutter observed the DRAW binding slot only, so glBindFramebuffer(
+            // GL_READ_FRAMEBUFFER, ...) moved nothing at all - which was harmless while
+            // nothing was emitted for the bit and is an UNDER-FIRE the moment P4a emits
+            // set_framebuffer_state per bound target (D-C2): the read record would never be
+            // sent and the server's ReadSurface would stay the previous framebuffer's. Over-
+            // firing costs one extra push; under-firing renders stale, and this file's own
+            // rule is that under-firing is the dangerous direction.
+            //
+            // A STORAGE REDEFINITION OF AN ATTACHED OBJECT MOVES THIS SHUTTER (P4a fable seam
+            // F-3), and the sentence that stood here - "a renderbuffer respecify is still
+            // invisible here, and deliberately so ... closed by emitting resource_respecify
+            // straight from the storage entry point" - was true of the RESOURCE record only.
+            // set_framebuffer_state inlines each attachment's InternalFormat, TextureTarget,
+            // extent, Samples and Complete (D-C1: "so the four cross-object masks fall out at
+            // push time with no lookup"), so `glTexImage2D(tex, RGB8); attach; draw;
+            // glTexImage2D(tex, RGBA8); draw` left the FRAMEBUFFER record saying RGB8 while the
+            // resource record said RGBA8, and the handle arm answered its alpha-widening,
+            // snorm-clamp and integer masks from the stale copy where the legacy arm re-read
+            // the frontend at the same re-sync - a proven arm divergence on a public-GL
+            // sequence. The fix is at the SETTER, not here: TextureObjectBase::PipePublish
+            // Descriptor and RenderbufferObject::PipePublishDescriptor - the one funnel every
+            // storage-defining entry point of either object takes, push-only - bump the
+            // attachment aggregate this shutter already reads. No counter is added to either
+            // object (G1), nothing widens this shutter onto the texture-content aggregate (which
+            // would fire the 304-byte record build on every glTexSubImage2D), and a storage
+            // definition of an UNATTACHED object over-fires it exactly once at load time.
+            //
+            // AND A TRAP THE NEXT NARROWING WOULD WALK INTO, recorded here because it is
+            // invisible from the shutter: FramebufferObject::SetDrawBuffer versions the VALUE
+            // being written rather than the index being written TO - it calls
+            // BumpAttachmentVersion(buffer). The object version and the aggregate still move,
+            // so THIS shutter is safe; a narrower one built on m_attachmentVersions would not
+            // be, and P4a must not build one.
             now[Index(MGPipeDirty::NewFramebuffer)] = MGPipeMixShutter(
+                MGPipeMixShutter(
                     ctx.GetAnyFramebufferAttachmentGeneration(),
                     m_framebufferBind.Observe(
-                    ctx.GetFramebufferBindingSlot(FramebufferTarget::Draw).GetVersion()));
-            now[Index(MGPipeDirty::NewSamplerViews)] =
-                MGPipeMixShutter(textureContent, ctx.GetTextureBindGeneration());
-            now[Index(MGPipeDirty::NewSamplers)] =
-                MGPipeMixShutter(textureParams, ctx.GetSamplingResolutionGeneration());
-            now[Index(MGPipeDirty::NewShaderImages)] =
-                MGPipeMixShutter(MGPipeMixShutter(textureContent, textureParams), programImages);
+                        ctx.GetFramebufferBindingSlot(FramebufferTarget::Draw).GetVersion())),
+                m_readFramebufferBind.Observe(
+                    ctx.GetFramebufferBindingSlot(FramebufferTarget::Read).GetVersion()));
+            // Bit 12 reads FOUR things (F-1): the two texture aggregates, the bind generation
+            // and the program input computed above. The params aggregate is here because
+            // SamplerEmit.h drops a unit's view to null when SamplesAsIncompleteTexture says so,
+            // and that predicate reads the effective sampler's filters - a glTexParameteri(
+            // MIN_FILTER) that completes a texture fired bit 13 and not this one, so the entry
+            // stayed null. The program input is here because the set is resolved FOR THE
+            // PROGRAM IN USE, and a glUseProgram alone moved nothing this shutter read.
+            now[Index(MGPipeDirty::NewSamplerViews)] = MGPipeMixShutter(
+                MGPipeMixShutter(MGPipeMixShutter(textureContent, textureParams), ctx.GetTextureBindGeneration()),
+                opaqueUnits);
+            // Bit 13, WIDENED AT P4a FOR BIT 11's REASON and found the same way. glBindSampler
+            // moves NEITHER half of what this used to read: GL_Sampler.cpp's BindSampler_State
+            // goes through NoteTextureUnitTouched and TextureUnit::SetSamplerObject, and both
+            // of those bump the TEXTURE BIND generation - bit 12's. The only two writers of
+            // BumpSamplingResolutionGeneration are PARAMETER changes (SamplerObject.cpp,
+            // TextureObject.cpp). So `glBindSampler(3, a); draw; glBindSampler(3, b); draw`
+            // fired bit 12 twice and bit 13 not once, and the server's BoundSamplerStates[3]
+            // went on naming a's CSO: wrong filtering, with nothing able to see it, because
+            // bind_sampler_states has no pulled twin to fall back on the way the view set does.
+            //
+            // MIXING THE GENERATION IN IS THE FIX RATHER THAN A SECOND GATE ON THE EMITTER,
+            // because that generation is what the unit SET is derived from: a sampler bind
+            // changes which sampler state applies at a unit, and a texture bind changes it too
+            // whenever the unit carries no sampler object and the texture's BUILT-IN sampler is
+            // what applies. Keeping it one shutter per bit is also what keeps the per-subsystem
+            // A/B and the per-bit fire tallies meaning what they say - a bit gated on another
+            // bit's shutter measures neither. The extra fires a plain texture bind now costs
+            // are swallowed by the emitter's own set-hash suppressor, which MGPipeTypes.h makes
+            // mandatory for every kVarTail set for this exact traffic.
+            now[Index(MGPipeDirty::NewSamplers)] = MGPipeMixShutter(
+                MGPipeMixShutter(textureParams, ctx.GetSamplingResolutionGeneration()),
+                ctx.GetTextureBindGeneration());
+            now[Index(MGPipeDirty::NewShaderImages)] = MGPipeMixShutter(
+            MGPipeMixShutter(MGPipeMixShutter(textureContent, textureParams), programImages),
+            ctx.GetTextureBindGeneration());
             now[Index(MGPipeDirty::NewConstBuffers)] = buffers;
             now[Index(MGPipeDirty::NewShaderBuffers)] = buffers;
             now[Index(MGPipeDirty::NewSoTargets)] =
@@ -380,6 +703,7 @@ namespace MobileGL::MG_Pipe {
             m_renderStateVersion.Reset();
             m_pipelineStateVersion.Reset();
             m_framebufferBind.Reset();
+            m_readFramebufferBind.Reset();
             m_indexSlotVersion.Reset();
             m_pack = PixelStoreParameters{};
             m_patch = PatchTrio{};
@@ -469,6 +793,12 @@ namespace MobileGL::MG_Pipe {
         // The draw framebuffer BINDING slot version, widened for the same reason: a Uint16
         // that wrapped would let a composite shutter repeat and cost a missed fire.
         MGPipeWidenedCounter m_framebufferBind;
+        // P4a: the READ framebuffer binding slot's version, its own counter for the same
+        // reason the draw one exists. Two counters rather than one over both slots: a single
+        // widened counter fed two independent Uint16s reads a decrease as a wrap on every
+        // alternation and would add 65536 per switch, which costs nothing in correctness
+        // (over-firing) but makes the high word meaningless.
+        MGPipeWidenedCounter m_readFramebufferBind;
         // The BOUND VAO's element-array slot version, widened for the same reason. One
         // counter over a slot that changes with the bound VAO: a stale high word can only
         // ADD a fire, never drop one, and the VAO identity in the same mix is what makes a
@@ -521,8 +851,14 @@ namespace MobileGL::MG_Pipe {
     // The monolith's one tracker. Under split there is one per client context; the context
     // identity check inside Update is what makes the single instance safe today.
     inline MGPipeTracker& MGPipeTrackerInstance() {
-        static MGPipeTracker tracker;
-        return tracker;
+        // NEVER DESTROYED, for MGPipeSlots()' reason (MG_Impl/Pipe/SlotAllocator.cpp). The
+        // rule is stated over the SET of MGPipe process singletons rather than over the two
+        // that a frontend destructor reaches today: which of them a destructor reaches is a
+        // property of the emitters, and the emitters change (C-1 added a second reaching
+        // path in one commit). One allocation per process, no destructor to lose - this type
+        // has none - and nothing can then answer a late call out of freed storage.
+        static MGPipeTracker* tracker = new MGPipeTracker();
+        return *tracker;
     }
 } // namespace MobileGL::MG_Pipe
 #endif // MOBILEGL_PIPE_PUSH

MobileGL/MG_Impl/Pipe/VertexInputEmit.h

@@ -431,8 +431,14 @@ namespace MobileGL::MG_Pipe {
     // The monolith's one vertex-input emitter, beside the tracker, the CSO cache, the
     // set-hash suppressor and the resource tracker.
     inline MGPipeVertexInputEmitter& MGPipeVertexInputEmitterInstance() {
-        static MGPipeVertexInputEmitter emitter;
-        return emitter;
+        // NEVER DESTROYED, for MGPipeSlots()' reason (MG_Impl/Pipe/SlotAllocator.cpp), and
+        // this one is not hypothetical: C-1 put this emitter DIRECTLY on ~VertexArrayObject's
+        // path - MGPipeEmitVertexElementsDestroyAndFree asks RecordIsPublished(handle) and
+        // then NoteRecordDestroyed(handle), which read and WRITE m_latch. A destroyed
+        // emitter answers out of a freed Vector and the write grows it, i.e. an operator
+        // new + memcpy + operator delete on an already-freed block.
+        static MGPipeVertexInputEmitter* emitter = new MGPipeVertexInputEmitter();
+        return *emitter;
     }
 } // namespace MobileGL::MG_Pipe
 #endif // MOBILEGL_PIPE_PUSH

MobileGL/MG_IntegrationTest/CMakeLists.txt

@@ -53,6 +53,9 @@ add_executable(MobileGLIntegrationTest
     Harness/HeadlessGL.cpp
     Harness/BackendCapsPeek.cpp
     Harness/PipeSlotPeek.cpp
+    Harness/PipeApplyPeek.cpp
+    Harness/P4aSeamPeek.cpp
+    Harness/P4aFinalFixPeek.cpp
     Scenarios/OrientationScenario.cpp
     Scenarios/CrossFrameBufferScenario.cpp
     Scenarios/ResidentIndexScenario.cpp
@@ -133,6 +136,11 @@ add_executable(MobileGLIntegrationTest
     Scenarios/HandleRecycleScenario.cpp
     Scenarios/CsoContentAddressingScenario.cpp
     Scenarios/ResourceSubsystemControlScenario.cpp
+    Scenarios/TextureParamsWithoutASamplerViewScenario.cpp
+    Scenarios/TextureUploadShapeScenario.cpp
+    Scenarios/ObjectSubsystemControlScenario.cpp
+    Scenarios/P4aSeamAuditScenario.cpp
+    Scenarios/P4aFinalFixScenario.cpp
 )
 
 target_include_directories(MobileGLIntegrationTest PRIVATE
@@ -405,6 +413,60 @@ function(mgl_itest_probe_for_symbol outVar directory symbolRegex)
     set(${outVar} "${mglItestProbeHit}" PARENT_SCOPE)
 endfunction()
 
+# The same probe, over a CONJUNCTION: BOTH regexes matched ANYWHERE UNDER the directory, not
+# necessarily in the same file. outVar is set to "<file matching A> + <file matching B>" when both
+# were found and to the empty string otherwise.
+#
+# P4a needs it for exactly one question and the question cannot be asked any other way. "Does
+# MOBILEGL_PIPE_HANDLE_ABA_CONTROL defeat the identity of P4a's OBJECT kinds on this backend?" is
+# not answered by "some source reads Features.PipeHandleAbaControl" - MagmaPipeArms.h does, and its
+# consumers are Magma's VERTEX-INPUT keys, so a single-regex probe would arm the six P4a ABA
+# controls on a backend where the knob cannot reach a texture, a framebuffer, a sampler, a view or a
+# program, and every one of them would assert a corruption nothing on the tree can produce - a hard
+# red on an always-on integration-gpu lane. Nor is it answered by "some source names a P4a subsystem
+# bit", which will become true for a backend that honours the mask long before anyone wires the
+# knob. What the arm needs is BOTH FACTS TO BE TRUE OF THE BACKEND.
+#
+# DIRECTORY-WIDE RATHER THAN PER FILE, and that is review finding F-M5 rather than a preference.
+# Requiring one file to carry both makes the arming depend on the FILE LAYOUT a later package
+# chooses: a backend that wires the knob in Managers.cpp while its P4a subsystem constants live in
+# SlotTables.h satisfies the question and fails the probe, the six controls keep printing wired=0
+# and asserting the correct pixels, and NOTHING fails, warns or records that the expected flip did
+# not happen - the one failure mode a control whose flip is in the future has. The false-positive
+# this trades against is a backend that reads the knob somewhere and names a P4a bit somewhere else
+# without connecting them; that costs a red lane an engineer must look at, which is the direction
+# that gets noticed. Both spellings of the answer are printed, so the configure log says which file
+# supplied which half.
+#
+# Same staleness guarantees as the single-regex probe: CONFIGURE_DEPENDS on the glob, and every file
+# it finds appended to CMAKE_CONFIGURE_DEPENDS.
+function(mgl_itest_probe_for_two_symbols outVar directory symbolRegexA symbolRegexB)
+    file(GLOB_RECURSE mglItestProbeSources CONFIGURE_DEPENDS
+        "${directory}/*.h" "${directory}/*.hpp" "${directory}/*.cpp" "${directory}/*.c")
+    set(mglItestProbeHitA "")
+    set(mglItestProbeHitB "")
+    foreach(mglItestProbeSource IN LISTS mglItestProbeSources)
+        set_property(DIRECTORY APPEND PROPERTY CMAKE_CONFIGURE_DEPENDS "${mglItestProbeSource}")
+        if (NOT mglItestProbeHitA)
+            file(STRINGS "${mglItestProbeSource}" mglItestProbeLinesA REGEX "${symbolRegexA}")
+            if (mglItestProbeLinesA)
+                set(mglItestProbeHitA "${mglItestProbeSource}")
+            endif()
+        endif()
+        if (NOT mglItestProbeHitB)
+            file(STRINGS "${mglItestProbeSource}" mglItestProbeLinesB REGEX "${symbolRegexB}")
+            if (mglItestProbeLinesB)
+                set(mglItestProbeHitB "${mglItestProbeSource}")
+            endif()
+        endif()
+    endforeach()
+    if (mglItestProbeHitA AND mglItestProbeHitB)
+        set(${outVar} "${mglItestProbeHitA} + ${mglItestProbeHitB}" PARENT_SCOPE)
+    else()
+        set(${outVar} "" PARENT_SCOPE)
+    endif()
+endfunction()
+
 if (MOBILEGL_PIPE_PUSH)
     # DirectGLES' Track H arm, probed by the subsystem bit it is gated on rather than by
     # SlotTables.h existing: the bit is declared in the contract (MG_Pipe/MGPipe.h:77) and the
@@ -490,6 +552,91 @@ if (MOBILEGL_PIPE_PUSH)
                        "mpr entries will SKIP")
     endif()
 
+    # P4a's THIRD re-key question, per backend, and it is not either of the two above. Bits 5/6
+    # re-keyed each backend's VERTEX-INPUT memos and bit 7/8 the BUFFER's; P4a re-keys six OBJECT
+    # classes - texture, renderbuffer, framebuffer, sampler CSO, sampler view, shader CSO - behind
+    # four new subsystem bits, and a backend has to NAME one of those constants to honour
+    # MOBILEGL_PIPE_PUSH's default mask. A P4a case that read either older marker would arm its
+    # Handles arm on a tree where nothing about a texture is keyed on a handle: green for a re-key
+    # that does not exist. Probed by the constants rather than by a file, for the reason the block
+    # above gives - packages D and E choose their own file layout.
+    foreach(mglItestObjectBackend DirectGLES DirectVulkan)
+        mgl_itest_probe_for_symbol(MGL_ITEST_OBJECT_REKEY
+            "${MGL_ITEST_ROOT}/MobileGL/MG_Backend/${mglItestObjectBackend}"
+            "kMGPipeSubsystem(Framebuffer|TextureResources|Samplers|Programs)")
+        if (MGL_ITEST_OBJECT_REKEY)
+            message(STATUS "Integration tests: ${mglItestObjectBackend} is keyed on {slot, gen} for "
+                           "P4a's object families (${MGL_ITEST_OBJECT_REKEY})")
+            list(APPEND MGL_ITEST_CAPABILITY_ENV
+                "MGITEST_HANDLE_REKEY_OBJECTS_${mglItestObjectBackend}=1")
+        else()
+            message(STATUS "Integration tests: no ${mglItestObjectBackend} source names "
+                           "kMGPipeSubsystem{Framebuffer,TextureResources,Samplers,Programs} - "
+                           "HandleRecycle's six P4a cases will SKIP their Handles arm on it")
+        endif()
+
+        # ...and whether the ABA knob reaches those kinds THERE. A conjunction over the WHOLE
+        # backend directory, for the reason mgl_itest_probe_for_two_symbols states: reading the
+        # knob is not the same as steering P4a's keys with it, so the weaker single-regex evidence
+        # would turn six always-on entries into a permanent red - but requiring one FILE to carry
+        # both halves would let a backend satisfy the question and miss the probe, and the six
+        # controls would then keep asserting the correct pixels with nothing recording that the
+        # flip was forgotten (F-M5).
+        mgl_itest_probe_for_two_symbols(MGL_ITEST_OBJECT_ABA
+            "${MGL_ITEST_ROOT}/MobileGL/MG_Backend/${mglItestObjectBackend}"
+            "PipeHandleAbaControl"
+            "kMGPipeSubsystem(Framebuffer|TextureResources|Samplers|Programs)")
+        if (MGL_ITEST_OBJECT_ABA)
+            message(STATUS "Integration tests: MOBILEGL_PIPE_HANDLE_ABA_CONTROL steers "
+                           "${mglItestObjectBackend}'s P4a object keys (${MGL_ITEST_OBJECT_ABA})")
+            list(APPEND MGL_ITEST_CAPABILITY_ENV
+                "MGITEST_HANDLE_ABA_OBJECTS_${mglItestObjectBackend}=1")
+        else()
+            message(STATUS "Integration tests: MobileGL/MG_Backend/${mglItestObjectBackend} does not "
+                           "both read Features.PipeHandleAbaControl and name a P4a subsystem bit "
+                           "somewhere under it - HandleRecycle's six P4a cases will assert the "
+                           "CORRECT pixels on the AbaControl arm and say that it is not a control "
+                           "for them yet")
+        endif()
+    endforeach()
+
+    # The client-side emitter of P4a's four suppressor-visible emission counters, which is what
+    # ObjectSubsystemControl reads. Same shape and same reason as the CSO and map-persistent
+    # emitter probes above: the emitters are minted in MG_Impl/Pipe (packages B and C), header-only
+    # by design (D-P), so the question is "does any source there emit it", not "does a named file
+    # exist". Until one does, every counter in the emit[] bracket is structurally zero in BOTH arms
+    # of the A/B and an assertion about their difference would be a statement about nothing.
+    mgl_itest_probe_for_symbol(MGL_ITEST_OBJECT_EMITTER
+        "${MGL_ITEST_ROOT}/MobileGL/MG_Impl/Pipe" "FramebufferEmissions")
+    if (MGL_ITEST_OBJECT_EMITTER)
+        message(STATUS "Integration tests: P4a's object emissions have an emitter "
+                       "(${MGL_ITEST_OBJECT_EMITTER})")
+        list(APPEND MGL_ITEST_CAPABILITY_ENV "MGITEST_PIPE_OBJECT_EMITTER_PRESENT=1")
+    else()
+        message(STATUS "Integration tests: no MG_Impl/Pipe source emits FramebufferEmissions - "
+                       "ObjectSubsystemControl's emission case will SKIP")
+    endif()
+
+    # ...and the CLIENT half of the texture-upload shape, separately, because it is a different
+    # question with a different owner's file behind it (review F-m7). ctu= is emitted by PipeStats
+    # in EVERY push build whether or not anything increments it, so "the counter read zero" and
+    # "no client emitter exists" are the same number and TextureUploadShape cannot tell them apart
+    # from the summary line alone. Once package B's texture emitter lands, an emitter that stopped
+    # emitting would read exactly like no emitter at all and the two-sided assertion the scenario
+    # exists for would pass while comparing nothing. This probe is what separates them.
+    mgl_itest_probe_for_symbol(MGL_ITEST_CLIENT_TEXTURE_UPLOAD_EMITTER
+        "${MGL_ITEST_ROOT}/MobileGL/MG_Impl/Pipe" "ClientTextureUploadEmissions")
+    if (MGL_ITEST_CLIENT_TEXTURE_UPLOAD_EMITTER)
+        message(STATUS "Integration tests: the client texture-upload counter has an emitter "
+                       "(${MGL_ITEST_CLIENT_TEXTURE_UPLOAD_EMITTER}) - TextureUploadShape's "
+                       "two-sided assertion is live")
+        list(APPEND MGL_ITEST_CAPABILITY_ENV "MGITEST_PIPE_CLIENT_TEXTURE_UPLOAD_EMITTER_PRESENT=1")
+    else()
+        message(STATUS "Integration tests: no MG_Impl/Pipe source emits "
+                       "ClientTextureUploadEmissions - TextureUploadShape records the SERVER shape "
+                       "only and asserts that ctu= is zero")
+    endif()
+
     mgl_itest_probe_for_symbol(MGL_ITEST_MAGMA_ABA
         "${MGL_ITEST_ROOT}/MobileGL/MG_Backend/DirectVulkan" "PipeHandleAbaControl")
     if (MGL_ITEST_MAGMA_ABA)
@@ -502,8 +649,9 @@ if (MOBILEGL_PIPE_PUSH)
     endif()
 else()
     message(STATUS "Integration tests: pull build - HandleRecycle.{Handles,AbaControl}, "
-                   "CsoContentAddressing and ResourceSubsystemControl stay registered (G2) and SKIP: "
-                   "every arm they assert is compiled only under MOBILEGL_PIPE_PUSH")
+                   "CsoContentAddressing, ResourceSubsystemControl, ObjectSubsystemControl and "
+                   "TextureUploadShape stay registered (G2) and SKIP: every arm they assert is "
+                   "compiled only under MOBILEGL_PIPE_PUSH")
 endif()
 
 mgl_itest_join_environment(MGL_ITEST_GLES_ENVIRONMENT
@@ -676,6 +824,36 @@ gtest_discover_tests(MobileGLIntegrationTest
         ENVIRONMENT "${MGL_ITEST_GLES_UNLOCATED_IO_BLOCKS_ENVIRONMENT}"
 )
 
+# P4a final review C-2: the dirty-then-delete case, with the allocator SCRIBBLING every freed
+# block. The defect this pins was a client emitter resolving a dead-but-not-recycled texture
+# handle to the freed ITextureObject* and calling a virtual on it from the next verb's drain;
+# whether that reads the object's ghost or faults depends on what the allocator did with the
+# block, so the ambient registrations above run the case as the application would see it and
+# these two run it with MALLOC_PERTURB_ set, where a resolved-but-dead pointer faults rather
+# than passes. Both backends: the death path is backend-neutral by ruling (ID-8).
+mgl_itest_join_environment(MGL_ITEST_GLES_MALLOC_PERTURB_ENVIRONMENT
+    "MOBILEGL_BACKEND_TYPE=DirectGLES" "MALLOC_PERTURB_=165" ${MGL_ITEST_COMMON_ENV})
+mgl_itest_join_environment(MGL_ITEST_VULKAN_MALLOC_PERTURB_ENVIRONMENT
+    "MOBILEGL_BACKEND_TYPE=DirectVulkan" "MALLOC_PERTURB_=165" ${MGL_ITEST_VULKAN_ENV})
+gtest_discover_tests(MobileGLIntegrationTest
+    TEST_PREFIX "DirectGLES.MallocPerturb."
+    TEST_FILTER "P4aFinalFixScenario.ADirtyTextureDeletedBeforeAnyVerbIsWalkedByTheNextDrain"
+    DISCOVERY_TIMEOUT 30
+    PROPERTIES
+        LABELS integration-gpu
+        TIMEOUT ${MGL_ITEST_TIMEOUT}
+        ENVIRONMENT "${MGL_ITEST_GLES_MALLOC_PERTURB_ENVIRONMENT}"
+)
+gtest_discover_tests(MobileGLIntegrationTest
+    TEST_PREFIX "DirectVulkan.MallocPerturb."
+    TEST_FILTER "P4aFinalFixScenario.ADirtyTextureDeletedBeforeAnyVerbIsWalkedByTheNextDrain"
+    DISCOVERY_TIMEOUT 30
+    PROPERTIES
+        LABELS integration-gpu
+        TIMEOUT ${MGL_ITEST_TIMEOUT}
+        ENVIRONMENT "${MGL_ITEST_VULKAN_MALLOC_PERTURB_ENVIRONMENT}"
+)
+
 # AsyncCompileScenario, with asynchronous compilation PINNED ON per backend.
 #
 # Not a duplicate of what the two ambient registrations already run: they run whatever
@@ -939,14 +1117,15 @@ gtest_discover_tests(MobileGLIntegrationTest
 # explicit bitmask below that leaked PUSH=0 turned this lane's LEGACY_MEMOS=0 into D14's armless
 # combination: the bring-up aborted, on purpose, and the lane went red for a reason that was never
 # about handles. The mask is the PHASE default, not a hand-picked bit, so the lane keeps measuring
-# the shape that ships: it was kMGPipeSubsystemsMigratedAtP2 (0x7f) and is now
-# kMGPipeSubsystemsMigratedAtP3a (0x1ff, MG_Pipe/MGPipe.h), which adds bit 7 (resources) and bit 8
-# (vertex input). Pinning it at 0x7f after P3a would leave the Handles arm asserting the P2 shape
-# while the buffer and vertex-input handles it is supposed to be about stayed switched off - a lane
-# that still passes and no longer measures the key that ships. Each phase's constant survives as the
-# NEXT phase's A/B control, which is what ResourceSubsystemControl's Off lane uses 0x7f for.
+# the shape that ships: it was kMGPipeSubsystemsMigratedAtP2 (0x7f), then
+# kMGPipeSubsystemsMigratedAtP3a (0x1ff), and is now kMGPipeSubsystemsMigratedAtP4a (0x1fff,
+# MG_Pipe/MGPipe.h), which adds bits 9-12 - framebuffer, texture resources, samplers and programs.
+# Pinning it at 0x1ff after P4a would leave the Handles arm asserting the P3a shape while the six
+# OBJECT handles it is now also about stayed switched off - a lane that still passes and no longer
+# measures the key that ships. Each phase's constant survives as the NEXT phase's A/B control, which
+# is what ResourceSubsystemControl's Off lane uses 0x7f for and ObjectSubsystemControl's uses 0x1ff.
 if (MOBILEGL_PIPE_PUSH)
-    set(MGL_ITEST_HANDLES_ARM_KNOBS "MOBILEGL_PIPE_LEGACY_MEMOS=0" "MOBILEGL_PIPE_PUSH=0x1ff")
+    set(MGL_ITEST_HANDLES_ARM_KNOBS "MOBILEGL_PIPE_LEGACY_MEMOS=0" "MOBILEGL_PIPE_PUSH=0x1fff")
     set(MGL_ITEST_ABA_ARM_KNOBS "MOBILEGL_PIPE_HANDLE_ABA_CONTROL=1")
 else()
     set(MGL_ITEST_HANDLES_ARM_KNOBS "")
@@ -1051,33 +1230,36 @@ gtest_discover_tests(MobileGLIntegrationTest
 # only thing these four lanes are an A/B about is `no CSO content addressing` (bit 63,
 # kMGPipeBehaviourNoCsoContentAddressing), which is what separates the On lane from the Off lane.
 # Every
-# other bit is the build's shipping mask, so it moves with the phase: it was 0x7f
-# (kMGPipeSubsystemsMigratedAtP2) and is now 0x1ff (kMGPipeSubsystemsMigratedAtP3a) for the same
-# reason MGL_ITEST_HANDLES_ARM_KNOBS above moved. Left pinned at 0x7f after P3a these lanes would
-# keep passing while running on a configuration nothing ships - bits 7 (resources) and 8 (vertex
-# input) cleared - which is the "still green, no longer measuring the shape that ships" failure
-# the Handles-arm comment above rejects. The counters they read (csom / csob) are render-state and
+# other bit is the build's shipping mask, so it moves with the phase: 0x7f
+# (kMGPipeSubsystemsMigratedAtP2), then 0x1ff (kMGPipeSubsystemsMigratedAtP3a), now 0x1fff
+# (kMGPipeSubsystemsMigratedAtP4a) for the same reason MGL_ITEST_HANDLES_ARM_KNOBS above moved. Left
+# pinned at 0x1ff after P4a these lanes would keep passing while running on a configuration nothing
+# ships - bits 9-12 (framebuffer, texture resources, samplers, programs) cleared - which is the
+# "still green, no longer measuring the shape that ships" failure the Handles-arm comment above
+# rejects. NOTE THAT THE OFF LANE'S MASK MOVED TOO, from 0x80000000000001ff to
+# 0x8000000000001fff: the mask moves with the phase, the control is bit 63, and the two must not be
+# confused. The counters they read (csom / csob) are render-state and
 # are steered by neither bit, so raising the mask is behaviour-preserving for what they assert;
 # what it buys is that a CSO regression that only shows up with the P3a subsystems on can reach
 # them. (contract-review-v1.md item 11, closed here for all three lane families.)
 mgl_itest_join_environment(MGL_ITEST_GLES_CSO_ON_ENVIRONMENT
     "MOBILEGL_BACKEND_TYPE=DirectGLES" "MGITEST_CSO_LANE=content-addressed"
-    "MOBILEGL_PIPE_PUSH=0x1ff" "MOBILEGL_PIPE_STATS=1" "MOBILEGL_PIPE_STATS_PERIOD=1"
+    "MOBILEGL_PIPE_PUSH=0x1fff" "MOBILEGL_PIPE_STATS=1" "MOBILEGL_PIPE_STATS_PERIOD=1"
     "MOBILEGL_LOG_FILE_PATH=${CMAKE_CURRENT_BINARY_DIR}/cso-content-addressed-DirectGLES.log"
     ${MGL_ITEST_CAPABILITY_ENV} ${MGL_ITEST_COMMON_ENV})
 mgl_itest_join_environment(MGL_ITEST_GLES_CSO_OFF_ENVIRONMENT
     "MOBILEGL_BACKEND_TYPE=DirectGLES" "MGITEST_CSO_LANE=no-content-addressing"
-    "MOBILEGL_PIPE_PUSH=0x80000000000001ff" "MOBILEGL_PIPE_STATS=1" "MOBILEGL_PIPE_STATS_PERIOD=1"
+    "MOBILEGL_PIPE_PUSH=0x8000000000001fff" "MOBILEGL_PIPE_STATS=1" "MOBILEGL_PIPE_STATS_PERIOD=1"
     "MOBILEGL_LOG_FILE_PATH=${CMAKE_CURRENT_BINARY_DIR}/cso-no-content-addressing-DirectGLES.log"
     ${MGL_ITEST_CAPABILITY_ENV} ${MGL_ITEST_COMMON_ENV})
 mgl_itest_join_environment(MGL_ITEST_VULKAN_CSO_ON_ENVIRONMENT
     "MOBILEGL_BACKEND_TYPE=DirectVulkan" "MGITEST_CSO_LANE=content-addressed"
-    "MOBILEGL_PIPE_PUSH=0x1ff" "MOBILEGL_PIPE_STATS=1" "MOBILEGL_PIPE_STATS_PERIOD=1"
+    "MOBILEGL_PIPE_PUSH=0x1fff" "MOBILEGL_PIPE_STATS=1" "MOBILEGL_PIPE_STATS_PERIOD=1"
     "MOBILEGL_LOG_FILE_PATH=${CMAKE_CURRENT_BINARY_DIR}/cso-content-addressed-DirectVulkan.log"
     ${MGL_ITEST_CAPABILITY_ENV} ${MGL_ITEST_VULKAN_ENV})
 mgl_itest_join_environment(MGL_ITEST_VULKAN_CSO_OFF_ENVIRONMENT
     "MOBILEGL_BACKEND_TYPE=DirectVulkan" "MGITEST_CSO_LANE=no-content-addressing"
-    "MOBILEGL_PIPE_PUSH=0x80000000000001ff" "MOBILEGL_PIPE_STATS=1" "MOBILEGL_PIPE_STATS_PERIOD=1"
+    "MOBILEGL_PIPE_PUSH=0x8000000000001fff" "MOBILEGL_PIPE_STATS=1" "MOBILEGL_PIPE_STATS_PERIOD=1"
     "MOBILEGL_LOG_FILE_PATH=${CMAKE_CURRENT_BINARY_DIR}/cso-no-content-addressing-DirectVulkan.log"
     ${MGL_ITEST_CAPABILITY_ENV} ${MGL_ITEST_VULKAN_ENV})
 
@@ -1120,12 +1302,15 @@ gtest_discover_tests(MobileGLIntegrationTest
 
 # --- G12: the P3a subsystem A/B, and G10's map-persistent-roundtrips lanes ------------
 #
-# THE MASKS ARE THE TWO PHASE CONSTANTS, not hand-picked bits: 0x1ff is
-# kMGPipeSubsystemsMigratedAtP3a (the push build's default) and 0x7f is
-# kMGPipeSubsystemsMigratedAtP2, which is exactly that default with bits 7 (resources) and 8
-# (vertex input) cleared. MGPipe.h:79 keeps each phase's constant alive as the next phase's A/B
-# control for this reason, and a lane that spelled its own bit pattern would stop being the shape
-# that ships the first time the default moved.
+# THE MASKS ARE PHASE CONSTANTS, not hand-picked bits: 0x1fff is
+# kMGPipeSubsystemsMigratedAtP4a (the push build's default as of P4a) and 0x7f is
+# kMGPipeSubsystemsMigratedAtP2, which is that default with bits 7 (resources), 8 (vertex input)
+# and 9-12 (P4a's four object families) cleared. MGPipe.h keeps each phase's constant alive as the
+# next phase's A/B control for this reason, and a lane that spelled its own bit pattern would stop
+# being the shape that ships the first time the default moved. THE ON LANE MOVED TO 0x1fff WITH THE
+# PHASE and the OFF LANE'S 0x7f DID NOT: this A/B is about bit 7, and pinning its On arm at 0x1ff
+# after P4a would measure the resource emitter on a configuration nothing ships. P4a's own A/B -
+# 0x1fff against 0x1ff - is ObjectSubsystemControl's, further down.
 #
 # DirectGLES only. P3a migrates Espryt's buffer and VAO paths; Magma's buffer path is P7 and
 # registers no MGPipeResourceOps, so a DirectVulkan arm would be measuring the client emitter
@@ -1146,7 +1331,7 @@ gtest_discover_tests(MobileGLIntegrationTest
 # the field inside the push guard), exactly as the HandleRecycle Legacy lanes already rely on.
 mgl_itest_join_environment(MGL_ITEST_GLES_RESOURCE_SUBSYSTEM_ON_ENVIRONMENT
     "MOBILEGL_BACKEND_TYPE=DirectGLES" "MGITEST_RESOURCE_SUBSYSTEM_LANE=on"
-    "MOBILEGL_PIPE_PUSH=0x1ff" "MOBILEGL_PIPE_STATS=1" "MOBILEGL_PIPE_STATS_PERIOD=1"
+    "MOBILEGL_PIPE_PUSH=0x1fff" "MOBILEGL_PIPE_STATS=1" "MOBILEGL_PIPE_STATS_PERIOD=1"
     "MOBILEGL_LOG_FILE_PATH=${CMAKE_CURRENT_BINARY_DIR}/resource-subsystem-on-DirectGLES.log"
     ${MGL_ITEST_CAPABILITY_ENV} ${MGL_ITEST_COMMON_ENV})
 mgl_itest_join_environment(MGL_ITEST_GLES_RESOURCE_SUBSYSTEM_OFF_ENVIRONMENT
@@ -1180,12 +1365,12 @@ gtest_discover_tests(MobileGLIntegrationTest
 # TEST_FILTER, for the private-log reason above.
 mgl_itest_join_environment(MGL_ITEST_GLES_MPR_REGROW_ENVIRONMENT
     "MOBILEGL_BACKEND_TYPE=DirectGLES" "MGITEST_MPR_LANE=storage-buffer-regrow"
-    "MOBILEGL_PIPE_PUSH=0x1ff" "MOBILEGL_PIPE_STATS=1" "MOBILEGL_PIPE_STATS_PERIOD=1"
+    "MOBILEGL_PIPE_PUSH=0x1fff" "MOBILEGL_PIPE_STATS=1" "MOBILEGL_PIPE_STATS_PERIOD=1"
     "MOBILEGL_LOG_FILE_PATH=${CMAKE_CURRENT_BINARY_DIR}/mpr-storage-buffer-regrow-DirectGLES.log"
     ${MGL_ITEST_CAPABILITY_ENV} ${MGL_ITEST_COMMON_ENV})
 mgl_itest_join_environment(MGL_ITEST_GLES_MPR_ARENA_ENVIRONMENT
     "MOBILEGL_BACKEND_TYPE=DirectGLES" "MGITEST_MPR_LANE=large-arena-adoption"
-    "MOBILEGL_PIPE_PUSH=0x1ff" "MOBILEGL_PIPE_STATS=1" "MOBILEGL_PIPE_STATS_PERIOD=1"
+    "MOBILEGL_PIPE_PUSH=0x1fff" "MOBILEGL_PIPE_STATS=1" "MOBILEGL_PIPE_STATS_PERIOD=1"
     "MOBILEGL_LOG_FILE_PATH=${CMAKE_CURRENT_BINARY_DIR}/mpr-large-arena-adoption-DirectGLES.log"
     ${MGL_ITEST_CAPABILITY_ENV} ${MGL_ITEST_COMMON_ENV})
 
@@ -1216,7 +1401,7 @@ gtest_discover_tests(MobileGLIntegrationTest
 # four processes to truncate. The fourth case skips in both lanes for exactly that reason, saying
 # so.
 mgl_itest_join_environment(MGL_ITEST_GLES_ARENA_SUBSYSTEM_ON_ENVIRONMENT
-    "MOBILEGL_BACKEND_TYPE=DirectGLES" "MOBILEGL_PIPE_PUSH=0x1ff"
+    "MOBILEGL_BACKEND_TYPE=DirectGLES" "MOBILEGL_PIPE_PUSH=0x1fff"
     ${MGL_ITEST_CAPABILITY_ENV} ${MGL_ITEST_COMMON_ENV})
 mgl_itest_join_environment(MGL_ITEST_GLES_ARENA_SUBSYSTEM_OFF_ENVIRONMENT
     "MOBILEGL_BACKEND_TYPE=DirectGLES" "MOBILEGL_PIPE_PUSH=0x7f"
@@ -1241,6 +1426,191 @@ gtest_discover_tests(MobileGLIntegrationTest
         ENVIRONMENT "${MGL_ITEST_GLES_ARENA_SUBSYSTEM_OFF_ENVIRONMENT}"
 )
 
+# --- G12: the P4a subsystem A/B, and its dependency refusal ---------------------------
+#
+# THE MASKS ARE THE TWO PHASE CONSTANTS, exactly as the P3a block above: 0x1fff is
+# kMGPipeSubsystemsMigratedAtP4a (the push build's default) and 0x1ff is
+# kMGPipeSubsystemsMigratedAtP3a, which is that default with bits 9 (framebuffer), 10 (texture
+# resources), 11 (samplers) and 12 (programs) cleared. THIS is the phase's "new 0x1ff off-lane": the
+# constant P3a shipped survives as P4a's A/B control, and a lane that spelled its own bit pattern
+# would stop being the shape that ships the first time the default moved.
+#
+# THE THIRD AND FOURTH LANES ARE THE DEPENDENCY REFUSALS (D-K2) and they are the entries in this
+# family that are not vacuous before the emitters land, because both are decisions made from the
+# bitmask alone. A half-honoured mask is invisible in the pixels by construction, which is why each
+# needs an entry rather than a code comment.
+#
+#   0x9ff sets the sampler subsystem (bit 11) WITHOUT the texture resource subsystem (bit 10) that
+#         every MGPBoundView::Texture and MGPImageView::Res depends on.
+#   0x5ff sets the texture resource subsystem (bit 10) WITHOUT the sampler subsystem (bit 11):
+#         D-K2's fourth row (ID-15). MGPTextureParams::BuiltinSampler is a SamplerCso handle and
+#         only bit 11 mints sampler CSOs, so bit 10 alone would emit a null there and the applier's
+#         Fatal is the next thing that happens. The brief called this pair harmless; P4a as built
+#         says otherwise, and the refusal belongs in the texture family's arm resolver.
+#
+# In both, the bring-up must log ONE error naming both bits and run the legacy arm.
+#
+# ONE CASE PER LANE, through TEST_FILTER, and it is a constraint rather than a preference: each case
+# READS the library's log and the log is a per-LANE resource (the library opens it fopen(path, "w"),
+# so every process in a lane truncates it). Two entries in one lane race under `ctest -j` with a
+# failure indistinguishable from "the counter was never emitted". Same rule as the CSO lanes, the
+# map-persistent lanes and the verify arming lane.
+#
+# THE FIRST FOUR LANES ARE DirectGLES ONLY. P4a migrates Espryt's framebuffer, texture, sampler
+# and program paths; Magma's are P7 and register nothing here, so a DirectVulkan lane that measured
+# the emit[] bracket would be measuring the client emitters against a backend nobody asked to
+# change.
+#
+# THE FIFTH AND SIXTH LANES INVERT THAT, and the inversion is the point (c0f, ID-39/ID-40). "Magma
+# registers no consumer" stopped being a reason to have no lane the moment it became a THING THE
+# CLIENT MUST CHECK: P4a's families were wired without P3a's "a backend registered
+# MGPipeResourceOps" conjunct, so on Magma the client emitted, the applier ACCEPTED, the client
+# cleared its dirty flags on that acceptance and Magma's legacy path found nothing to upload - 66
+# DirectVulkan cases red, every one of them texture-upload shaped, every one of them green at
+# 0x1ff. The fix's belt (the applier refusing and counting RefusedNoConsumer) is invisible in
+# pixels and invisible in the emit[] bracket, so it needs its own entry, and it needs it on the
+# backend WITHOUT the consumer. The DirectGLES twin is the control that keeps the assertion from
+# being vacuously true of a tree where nothing emits anywhere.
+#
+# Both run at the PHASE DEFAULT (0x1fff) rather than a hand-picked mask, for the reason the whole
+# block gives: the shape that ships is the shape worth measuring.
+#
+# Registered in EVERY build, including the pull build where none of the counters exists, so that
+# `ctest -L integration-gpu` stays name-for-name identical between pull and push (gate G2). In a
+# pull build MGITEST_PIPE_PUSH_BUILD is absent and every one of these cases skips saying so.
+mgl_itest_join_environment(MGL_ITEST_GLES_OBJECT_SUBSYSTEM_ON_ENVIRONMENT
+    "MOBILEGL_BACKEND_TYPE=DirectGLES" "MGITEST_OBJECT_SUBSYSTEM_LANE=on"
+    "MOBILEGL_PIPE_PUSH=0x1fff" "MOBILEGL_PIPE_STATS=1" "MOBILEGL_PIPE_STATS_PERIOD=1"
+    "MOBILEGL_LOG_FILE_PATH=${CMAKE_CURRENT_BINARY_DIR}/object-subsystem-on-DirectGLES.log"
+    ${MGL_ITEST_CAPABILITY_ENV} ${MGL_ITEST_COMMON_ENV})
+mgl_itest_join_environment(MGL_ITEST_GLES_OBJECT_SUBSYSTEM_OFF_ENVIRONMENT
+    "MOBILEGL_BACKEND_TYPE=DirectGLES" "MGITEST_OBJECT_SUBSYSTEM_LANE=off"
+    "MOBILEGL_PIPE_PUSH=0x1ff" "MOBILEGL_PIPE_STATS=1" "MOBILEGL_PIPE_STATS_PERIOD=1"
+    "MOBILEGL_LOG_FILE_PATH=${CMAKE_CURRENT_BINARY_DIR}/object-subsystem-off-DirectGLES.log"
+    ${MGL_ITEST_CAPABILITY_ENV} ${MGL_ITEST_COMMON_ENV})
+mgl_itest_join_environment(MGL_ITEST_GLES_OBJECT_SUBSYSTEM_REFUSED_ENVIRONMENT
+    "MOBILEGL_BACKEND_TYPE=DirectGLES" "MGITEST_OBJECT_SUBSYSTEM_LANE=refused"
+    "MOBILEGL_PIPE_PUSH=0x9ff" "MOBILEGL_PIPE_STATS=1" "MOBILEGL_PIPE_STATS_PERIOD=1"
+    "MOBILEGL_LOG_FILE_PATH=${CMAKE_CURRENT_BINARY_DIR}/object-subsystem-refused-DirectGLES.log"
+    ${MGL_ITEST_CAPABILITY_ENV} ${MGL_ITEST_COMMON_ENV})
+mgl_itest_join_environment(MGL_ITEST_GLES_OBJECT_SUBSYSTEM_REFUSED_TEXTURE_ENVIRONMENT
+    "MOBILEGL_BACKEND_TYPE=DirectGLES" "MGITEST_OBJECT_SUBSYSTEM_LANE=refused-texture"
+    "MOBILEGL_PIPE_PUSH=0x5ff" "MOBILEGL_PIPE_STATS=1" "MOBILEGL_PIPE_STATS_PERIOD=1"
+    "MOBILEGL_LOG_FILE_PATH=${CMAKE_CURRENT_BINARY_DIR}/object-subsystem-refused-texture-DirectGLES.log"
+    ${MGL_ITEST_CAPABILITY_ENV} ${MGL_ITEST_COMMON_ENV})
+mgl_itest_join_environment(MGL_ITEST_GLES_OBJECT_SUBSYSTEM_CONSUMER_ENVIRONMENT
+    "MOBILEGL_BACKEND_TYPE=DirectGLES" "MGITEST_OBJECT_SUBSYSTEM_LANE=consumer"
+    "MOBILEGL_PIPE_PUSH=0x1fff" "MOBILEGL_PIPE_STATS=1" "MOBILEGL_PIPE_STATS_PERIOD=1"
+    "MOBILEGL_LOG_FILE_PATH=${CMAKE_CURRENT_BINARY_DIR}/object-subsystem-consumer-DirectGLES.log"
+    ${MGL_ITEST_CAPABILITY_ENV} ${MGL_ITEST_COMMON_ENV})
+mgl_itest_join_environment(MGL_ITEST_VULKAN_OBJECT_SUBSYSTEM_NO_CONSUMER_ENVIRONMENT
+    "MOBILEGL_BACKEND_TYPE=DirectVulkan" "MGITEST_OBJECT_SUBSYSTEM_LANE=no-consumer"
+    "MOBILEGL_PIPE_PUSH=0x1fff" "MOBILEGL_PIPE_STATS=1" "MOBILEGL_PIPE_STATS_PERIOD=1"
+    "MOBILEGL_LOG_FILE_PATH=${CMAKE_CURRENT_BINARY_DIR}/object-subsystem-no-consumer-DirectVulkan.log"
+    ${MGL_ITEST_CAPABILITY_ENV} ${MGL_ITEST_VULKAN_ENV})
+
+gtest_discover_tests(MobileGLIntegrationTest
+    TEST_PREFIX "DirectGLES.ObjectSubsystemControl.On."
+    TEST_FILTER "ObjectSubsystemControlScenario.ClearingTheP4aBitsStopsTheEmissionsAndNotThePixels"
+    DISCOVERY_TIMEOUT 30
+    PROPERTIES
+        LABELS integration-gpu
+        TIMEOUT ${MGL_ITEST_TIMEOUT}
+        ENVIRONMENT "${MGL_ITEST_GLES_OBJECT_SUBSYSTEM_ON_ENVIRONMENT}"
+)
+gtest_discover_tests(MobileGLIntegrationTest
+    TEST_PREFIX "DirectGLES.ObjectSubsystemControl.Off."
+    TEST_FILTER "ObjectSubsystemControlScenario.ClearingTheP4aBitsStopsTheEmissionsAndNotThePixels"
+    DISCOVERY_TIMEOUT 30
+    PROPERTIES
+        LABELS integration-gpu
+        TIMEOUT ${MGL_ITEST_TIMEOUT}
+        ENVIRONMENT "${MGL_ITEST_GLES_OBJECT_SUBSYSTEM_OFF_ENVIRONMENT}"
+)
+gtest_discover_tests(MobileGLIntegrationTest
+    TEST_PREFIX "DirectGLES.ObjectSubsystemControl.Refused."
+    TEST_FILTER "ObjectSubsystemControlScenario.ASamplerBitWithoutTheTextureBitIsRefusedAndNamed"
+    DISCOVERY_TIMEOUT 30
+    PROPERTIES
+        LABELS integration-gpu
+        TIMEOUT ${MGL_ITEST_TIMEOUT}
+        ENVIRONMENT "${MGL_ITEST_GLES_OBJECT_SUBSYSTEM_REFUSED_ENVIRONMENT}"
+)
+gtest_discover_tests(MobileGLIntegrationTest
+    TEST_PREFIX "DirectGLES.ObjectSubsystemControl.RefusedTexture."
+    TEST_FILTER "ObjectSubsystemControlScenario.ATextureBitWithoutTheSamplerBitIsRefusedAndNamed"
+    DISCOVERY_TIMEOUT 30
+    PROPERTIES
+        LABELS integration-gpu
+        TIMEOUT ${MGL_ITEST_TIMEOUT}
+        ENVIRONMENT "${MGL_ITEST_GLES_OBJECT_SUBSYSTEM_REFUSED_TEXTURE_ENVIRONMENT}"
+)
+gtest_discover_tests(MobileGLIntegrationTest
+    TEST_PREFIX "DirectGLES.ObjectSubsystemControl.Consumer."
+    TEST_FILTER "ObjectSubsystemControlScenario.TheAppliersNoConsumerBeltNeverFiresBehindTheClientsGate"
+    DISCOVERY_TIMEOUT 30
+    PROPERTIES
+        LABELS integration-gpu
+        TIMEOUT ${MGL_ITEST_TIMEOUT}
+        ENVIRONMENT "${MGL_ITEST_GLES_OBJECT_SUBSYSTEM_CONSUMER_ENVIRONMENT}"
+)
+gtest_discover_tests(MobileGLIntegrationTest
+    TEST_PREFIX "DirectVulkan.ObjectSubsystemControl.NoConsumer."
+    TEST_FILTER "ObjectSubsystemControlScenario.TheAppliersNoConsumerBeltNeverFiresBehindTheClientsGate"
+    DISCOVERY_TIMEOUT 30
+    PROPERTIES
+        LABELS integration-gpu
+        TIMEOUT ${MGL_ITEST_TIMEOUT}
+        ENVIRONMENT "${MGL_ITEST_VULKAN_OBJECT_SUBSYSTEM_NO_CONSUMER_ENVIRONMENT}"
+)
+
+# --- The texture upload shape: RECORDED, NOT GATED in P4a (D-D4) ----------------------
+#
+# SSIM is blind to the box-versus-rect upload shape and the Mali cliff it hides is ~+6 ms/frame, so
+# the shape needs a number - two numbers, in fact, the server's tex[emit= box= rect= jobs=] and the
+# client's emit[ctu=], which agreeing is the whole reason both are published (D-L). What this lane
+# asserts is that the numbers could be READ, that the server bracket's own arithmetic holds and that
+# the two sides agree when both are non-zero; WHICH shape each texture took is RecordProperty'd and
+# printed for MEASUREMENTS.md. P3b/P4b turns it into a gate against a gold standard, with the Mali
+# frame-time delta published beside it - gating a shape this phase has not finished deciding would
+# either pin today's shape as the answer or fail on the change that is the next phase's point.
+#
+# Its own log path and its own single-case filter, for the per-lane-log reason above.
+mgl_itest_join_environment(MGL_ITEST_GLES_TEXTURE_UPLOAD_SHAPE_ENVIRONMENT
+    "MOBILEGL_BACKEND_TYPE=DirectGLES" "MGITEST_TEXTURE_UPLOAD_SHAPE_LANE=1"
+    "MOBILEGL_PIPE_PUSH=0x1fff" "MOBILEGL_PIPE_STATS=1" "MOBILEGL_PIPE_STATS_PERIOD=1"
+    "MOBILEGL_LOG_FILE_PATH=${CMAKE_CURRENT_BINARY_DIR}/texture-upload-shape-DirectGLES.log"
+    ${MGL_ITEST_CAPABILITY_ENV} ${MGL_ITEST_COMMON_ENV})
+
+gtest_discover_tests(MobileGLIntegrationTest
+    TEST_PREFIX "DirectGLES.TextureUploadShape."
+    TEST_FILTER "TextureUploadShapeScenario.TheEmittedUploadShapeIsRecordedAndTheTwoSidesAgree"
+    DISCOVERY_TIMEOUT 30
+    PROPERTIES
+        LABELS integration-gpu
+        TIMEOUT ${MGL_ITEST_TIMEOUT}
+        ENVIRONMENT "${MGL_ITEST_GLES_TEXTURE_UPLOAD_SHAPE_ENVIRONMENT}"
+)
+
+# --- G9: the mandatory red-before scenario -------------------------------------------
+#
+# TextureParamsWithoutASamplerViewScenario needs NO lane of its own, and that is deliberate rather
+# than an omission. It reads no counter and no log - its observable is a sampled colour - and its
+# claim is about the SHIPPING configuration, so the two ambient registrations at the top of this
+# file (which run at the build's default mask) are exactly the arms it wants. A lane here would pin
+# a mask and make the entry stop describing what ships the next time the default moved. The
+# DirectVulkan ambient entries skip in the scenario's SetUp, naming the backend: the gap it is about
+# is Espryt's SyncAttachmentObject / SyncNeccessaryTextures pair and P4a touches no DirectVulkan
+# source but MagmaPipeArms.h (D-Q).
+#
+# D-E3 expects its second case, AReadAttachmentOnlyTexturesDepthStencilModeReachesTheDriver, to be
+# RED until package esprytobj lands. MEASURED ON THE CONTRACT COMMIT IT IS GREEN, and the scenario's
+# header carries the mechanism: a texture parameter's only public-GL observable is a sample, and the
+# sample repairs the state it was meant to catch (the unit sync list re-syncs whenever the params
+# version moved). Nothing about any of that is expressed in this file - a registration that
+# "expected" a red would be a gate that could never go green - and the ruling on the missing
+# artefact is the integrator's, recorded in the gates result document.
+
 if (MOBILEGL_PIPE_VERIFY)
     # 900s, not the ambient 120: the comparator re-reads every field of the fill mask at the verb
     # boundary and again at every accessor read, which the design budgets at 5-10x.

MobileGL/MG_IntegrationTest/Harness/P4aFinalFixPeek.cpp

@@ -0,0 +1,71 @@
+// MobileGL - MobileGL/MG_IntegrationTest/Harness/P4aFinalFixPeek.cpp
+// Copyright (c) 2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+
+#include "P4aFinalFixPeek.h"
+
+#if !defined(__ANDROID__)
+#include <MG_Pipe/MGPipe.h>
+#if MOBILEGL_PIPE_PUSH
+#include <MG_Pipe/MGPipeTypes.h>
+#include <MG_Pipe/PipeApply.h>
+#include <MG_Util/Metrics/PipeStats.h>
+#define MGITEST_P4A_FINALFIX_PEEK_LIVE 1
+#endif
+#endif
+
+namespace MGITest {
+
+#if defined(MGITEST_P4A_FINALFIX_PEEK_LIVE)
+    namespace {
+        namespace MGP = MobileGL::MG_Pipe;
+    } // namespace
+
+    bool PeekPipeTextureResourceRecord(unsigned glTextureName, PipeTextureResourceRecordPeek* out) {
+        if (out == nullptr) return false;
+        const MGP::MGPipeApplierState& applier = MGP::MGPipeApplier();
+        // Slot 0 is the reserved null slot; the walk is the same shape PipeApplyPeek.cpp's
+        // params reading takes. A GL name is never an identity on the wire, which is exactly
+        // why it is the right key for a harness that starts from the application's view.
+        for (MobileGL::SizeT slot = 1; slot < applier.TextureResources.size(); ++slot) {
+            const MGP::MGPipeResourceRecord& record = applier.TextureResources[slot];
+            if (!record.Live) continue;
+            if (record.Desc.GlNameForDiag != static_cast<MobileGL::Uint32>(glTextureName)) continue;
+            out->Slot = static_cast<unsigned>(slot);
+            out->Gen = static_cast<unsigned>(record.Gen);
+            out->Serial = static_cast<unsigned long long>(record.Serial);
+            out->BindMask = static_cast<unsigned>(record.Desc.BindMask);
+            out->ImageBindableHint = static_cast<unsigned>(record.Desc.ImageBindableHint);
+            out->Levels = static_cast<unsigned>(record.Desc.Levels);
+            out->PendingUploads = static_cast<unsigned>(record.PendingUploads.size());
+            return true;
+        }
+        return false;
+    }
+
+    bool PeekPipeStatsTextureRemintPulls(unsigned long long* out) {
+        if (out == nullptr) return false;
+        namespace Stats = MobileGL::MG_Util::PipeStats;
+        if (!Stats::Enabled()) Stats::SetEnabledForTesting(true);
+        *out = static_cast<unsigned long long>(Stats::TotalCalls(Stats::CallClass::TextureRemintPulls));
+        return true;
+    }
+
+    bool PeekPipeStatsTextureUploadEmissions(unsigned long long* out) {
+        if (out == nullptr) return false;
+        namespace Stats = MobileGL::MG_Util::PipeStats;
+        if (!Stats::Enabled()) Stats::SetEnabledForTesting(true);
+        *out = static_cast<unsigned long long>(Stats::TotalCalls(Stats::CallClass::TextureUploadEmissions));
+        return true;
+    }
+#else
+    bool PeekPipeTextureResourceRecord(unsigned, PipeTextureResourceRecordPeek*) { return false; }
+    bool PeekPipeStatsTextureRemintPulls(unsigned long long*) { return false; }
+    bool PeekPipeStatsTextureUploadEmissions(unsigned long long*) { return false; }
+#endif
+
+} // namespace MGITest

MobileGL/MG_IntegrationTest/Harness/P4aFinalFixPeek.h

@@ -0,0 +1,41 @@
+// MobileGL - MobileGL/MG_IntegrationTest/Harness/P4aFinalFixPeek.h
+// Copyright (c) 2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+//
+// The white-box readings P4aFinalFixScenario.cpp takes, in a translation unit of their own for
+// P4aSeamPeek.h's reason: a scenario TU includes the GL prototype headers and cannot include
+// MG_Pipe/PipeApply.h or the Espryt managers beside them, and PipeApplyPeek.cpp is the gates
+// package's file. Every entry point answers false where the reading cannot be taken (a pull
+// build, Android, or an applier that holds no record for the name), and a false teaches the
+// caller nothing - the case declines that half by name and keeps its public-GL verdict.
+#pragma once
+
+namespace MGITest {
+
+    // The applier's resource record for a texture, found by its GL name (GlNameForDiag - a
+    // diagnostics-only field, which is exactly what a test harness is).
+    struct PipeTextureResourceRecordPeek {
+        unsigned Slot;
+        unsigned Gen;
+        unsigned long long Serial;
+        unsigned BindMask;
+        unsigned ImageBindableHint;
+        unsigned Levels;
+        unsigned PendingUploads;
+    };
+    bool PeekPipeTextureResourceRecord(unsigned glTextureName, PipeTextureResourceRecordPeek* out);
+
+    // The process-wide texture-remint pull count (PipeStats "tex-remint-pulls", `trp=` on the
+    // summary line; ROADMAP open question 2). Arms the PipeStats counters for this process on
+    // the first call, which is what lets a case read the number without a stats-enabled lane.
+    bool PeekPipeStatsTextureRemintPulls(unsigned long long* out);
+    // Espryt's count of texture uploads it actually issued (PipeStats "tex-upload-emissions"):
+    // what tells a CONSUMED pending upload apart from a DROPPED one, since the record's set is
+    // empty either way. Arms the counters the same way.
+    bool PeekPipeStatsTextureUploadEmissions(unsigned long long* out);
+
+} // namespace MGITest

MobileGL/MG_IntegrationTest/Harness/P4aSeamPeek.cpp

@@ -0,0 +1,107 @@
+// MobileGL - MobileGL/MG_IntegrationTest/Harness/P4aSeamPeek.cpp
+// Copyright (c) 2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+
+#include "P4aSeamPeek.h"
+
+#if !defined(__ANDROID__)
+#include <MG_Pipe/MGPipe.h>
+#if MOBILEGL_PIPE_PUSH
+#include <MG_Pipe/PipeApply.h>
+#include <MG_State/GLState/Core.h>
+#include <MG_Backend/DirectGLES/Managers.h>
+#include <MG_Backend/DirectGLES/DirectGLES.h>
+#define MGITEST_P4A_SEAM_PEEK_LIVE 1
+#endif
+#endif
+
+namespace MGITest {
+
+#if defined(MGITEST_P4A_SEAM_PEEK_LIVE)
+    namespace {
+        namespace MGP = MobileGL::MG_Pipe;
+        namespace MGB = MobileGL::MG_Backend::DirectGLES;
+
+        // "Is Espryt the backend running" - the same test PipeApplyPeek.cpp makes through a twin:
+        // on Magma no ES entry point was ever resolved and every member of g_GLESFuncs is null.
+        // It is asked BEFORE SamplerSubsystemEnabled(), which is Espryt's own latch and must not
+        // be resolved on a process whose backend is not Espryt.
+        bool EsprytIsRunning() { return MGB::g_GLESFuncs.glBindSampler != nullptr; }
+    } // namespace
+
+    bool PeekEsprytSamplerHandleArmIsLive(bool* outLive) {
+        if (outLive == nullptr) return false;
+        if (!EsprytIsRunning()) return false;
+        *outLive = MGB::SamplerSubsystemEnabled();
+        return true;
+    }
+
+    bool PeekEsprytFramebufferHandleArmIsLive(bool* outLive) {
+        if (outLive == nullptr) return false;
+        if (!EsprytIsRunning()) return false;
+        *outLive = MGB::FramebufferSubsystemEnabled();
+        return true;
+    }
+
+    bool PeekPipeShaderImageWindow(PipeShaderImageWindowPeek* out) {
+        if (out == nullptr) return false;
+        const MGP::MGPipeApplierState& applier = MGP::MGPipeApplier();
+        out->Start = static_cast<unsigned>(applier.ShaderImageStart);
+        out->Count = static_cast<unsigned>(applier.ShaderImageCount);
+        out->Serial = static_cast<unsigned long long>(applier.ShaderImagesSerial);
+        return true;
+    }
+
+    bool PeekEsprytUnitSampler(unsigned unit, unsigned glSamplerName, EsprytUnitSamplerPeek* out) {
+        if (out == nullptr) return false;
+        if (!EsprytIsRunning()) return false;
+        if (!MobileGL::MG_State::pGLContext) return false;
+        const MGP::MGPipeApplierState& applier = MGP::MGPipeApplier();
+        if (unit >= applier.BoundSamplerStates.size() || unit >= MGB::SamplerImpl::g_boundSamplersCache.size()) {
+            return false;
+        }
+        *out = EsprytUnitSamplerPeek{};
+
+        // Espryt's own binding shadow: every glBindSampler this backend issues routes through it
+        // (BackendSamplerObject::Bind / UnbindSampler), so it IS what the driver holds.
+        if (MGB::SamplerImpl::BackendSamplerObject* const bound = MGB::SamplerImpl::g_boundSamplersCache[unit]) {
+            out->BoundSamplerId = static_cast<unsigned>(bound->GetBackendSamplerId());
+        }
+
+        const MGP::MGPipeHandle cso = applier.BoundSamplerStates[unit];
+        out->CsoHandleSlot = static_cast<unsigned>(cso.Slot);
+        out->CsoHandleGen = static_cast<unsigned>(cso.Gen);
+        out->UnitInsideWindow = unit >= applier.SamplerStateStart &&
+                                unit - applier.SamplerStateStart < applier.SamplerStateCount;
+        // The twin AT THE CSO HANDLE, asked of the same table Espryt asks (FindByHandle): a null
+        // here with a live handle is the F-4 shape - a content-addressed handle looked up in a
+        // table that only ever held identity-minted slots.
+        if (!MGP::MGPipeHandleIsNull(cso)) {
+            if (auto* const slot = MGB::SamplerImpl::g_backendSamplerObjects.FindByHandle(cso); slot && *slot) {
+                out->CsoTwinSamplerId = static_cast<unsigned>((*slot)->GetBackendSamplerId());
+            }
+        }
+
+        // And the twin keyed on the frontend OBJECT, which is what the pre-handle program pass
+        // used to mint and bind, so a scenario can say which of the two the driver holds.
+        const auto& object = MobileGL::MG_State::pGLContext->GetSamplerObject(
+            static_cast<MobileGL::Uint>(glSamplerName));
+        if (object) {
+            if (auto* const slot = MGB::SamplerImpl::g_backendSamplerObjects.Find(object.get()); slot && *slot) {
+                out->IdentityTwinSamplerId = static_cast<unsigned>((*slot)->GetBackendSamplerId());
+            }
+        }
+        return true;
+    }
+#else
+    bool PeekEsprytSamplerHandleArmIsLive(bool*) { return false; }
+    bool PeekEsprytFramebufferHandleArmIsLive(bool*) { return false; }
+    bool PeekPipeShaderImageWindow(PipeShaderImageWindowPeek*) { return false; }
+    bool PeekEsprytUnitSampler(unsigned, unsigned, EsprytUnitSamplerPeek*) { return false; }
+#endif
+
+} // namespace MGITest

MobileGL/MG_IntegrationTest/Harness/P4aSeamPeek.h

@@ -0,0 +1,78 @@
+// MobileGL - MobileGL/MG_IntegrationTest/Harness/P4aSeamPeek.h
+// Copyright (c) 2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+//
+// The three readings P4aSeamAuditScenario.cpp takes from the inside, for the two seams the fable
+// seam audit proved that PUBLIC GL CANNOT SEE: F-4 (the record arm's sampler bind is a permanent
+// no-op, hidden by the pre-handle program pass binding the same values) and F-2 / SD-4 (the
+// shader-image window does not follow a program switch, hidden by the server's window/high-water
+// union taking the pre-handle bind for the units outside it). Both are correct pictures over a
+// permanent silent fallback, which is precisely the class ROADMAP.md:20 says a gate has to be
+// able to make red - and the only place the difference exists is inside.
+//
+// A SEPARATE TRANSLATION UNIT for PipeApplyPeek.h's reason, verbatim: this file includes
+// Espryt's own Managers.h, which may not meet a scenario's GL headers in one file. It is NOT
+// PipeApplyPeek.cpp because that file is package F's (gates v3) and this round may not edit it.
+//
+// EVERY ENTRY POINT RETURNS false, TOUCHING NOTHING, WHERE IT CANNOT LOOK - a pull build, Android,
+// a backend that is not Espryt - and a caller that gets false has learned NOTHING: "could not
+// look" is not "was bound". The scenario declines the reading BY NAME and keeps its public-GL
+// half, which is the shape TextureParamsWithoutASamplerViewScenario.cpp argues for.
+
+#pragma once
+
+namespace MGITest {
+
+    // ---- is Espryt's sampler family on its HANDLE arm in this process? -------------------
+    //
+    // The gate for every other reading here. True only on DirectGLES, in a push build, with
+    // Espryt's own resolver answering "handle" for kMGPipeSubsystemSamplers (bit 11 set and its
+    // dependency satisfied) - i.e. exactly when bind_sampler_states / set_shader_images are
+    // consumed, so a white-box assertion about them can be red for its own reason and for no
+    // other. Written only on true.
+    bool PeekEsprytSamplerHandleArmIsLive(bool* outLive);
+
+    // The same question for the FRAMEBUFFER family (bit 9): true when Espryt consumes
+    // set_framebuffer_state in this process. The renderbuffer half of the F-3 case asserts only
+    // there - on the pre-handle arm a renderbuffer re-storaged while attached moves nothing the
+    // FBO memo reads (D-D2's documented hole, pre-P4a code), and the record is what closes it.
+    bool PeekEsprytFramebufferHandleArmIsLive(bool* outLive);
+
+    // ---- the applier's shader-image window, as last received ------------------------------
+    //
+    // MGPipeApplierState::ShaderImageStart / ShaderImageCount / ShaderImagesSerial. Count is
+    // "how many units set_shader_images last described" - 0 means the set has NEVER arrived
+    // (MGPipeApplierReset advances the serial whether or not anything was emitted, so the serial
+    // is not that test). Push build only.
+    struct PipeShaderImageWindowPeek {
+        unsigned Start;
+        unsigned Count;
+        unsigned long long Serial;
+    };
+
+    bool PeekPipeShaderImageWindow(PipeShaderImageWindowPeek* out);
+
+    // ---- which driver sampler a texture unit is bound to, and whose twin it is -------------
+    //
+    // For F-4. `BoundSamplerId` is the ES sampler name Espryt's own binding shadow says unit
+    // `unit` carries (0 = none). `CsoHandleSlot/Gen` is bind_sampler_states' handle for the unit,
+    // `CsoTwinSamplerId` the ES name of the twin Espryt holds AT THAT HANDLE (0 = no twin at the
+    // content-addressed slot - the F-4 shape), and `IdentityTwinSamplerId` the ES name of a twin
+    // keyed on the frontend SamplerObject named `glSamplerName` (0 = none). On a correct handle
+    // arm the unit's driver sampler IS the CSO twin. Push build, DirectGLES only.
+    struct EsprytUnitSamplerPeek {
+        unsigned BoundSamplerId;
+        unsigned CsoHandleSlot;
+        unsigned CsoHandleGen;
+        bool UnitInsideWindow;
+        unsigned CsoTwinSamplerId;
+        unsigned IdentityTwinSamplerId;
+    };
+
+    bool PeekEsprytUnitSampler(unsigned unit, unsigned glSamplerName, EsprytUnitSamplerPeek* out);
+
+} // namespace MGITest

MobileGL/MG_IntegrationTest/Harness/PipeApplyPeek.cpp

@@ -0,0 +1,188 @@
+// MobileGL - MobileGL/MG_IntegrationTest/Harness/PipeApplyPeek.cpp
+// Copyright (c) 2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+
+#include "PipeApplyPeek.h"
+
+#if !defined(__ANDROID__)
+#include <MG_Pipe/MGPipe.h>
+#if MOBILEGL_PIPE_PUSH
+#include <MG_Pipe/PipeApply.h>
+#include <MG_Pipe/MGPipeTypes.h>
+#include <MG_State/GLState/Core.h>
+#include <MG_Util/Converters/MGToGL/TextureEnumConverter.h>
+#include <MG_Backend/DirectGLES/Managers.h>
+#include <MG_Backend/DirectGLES/DirectGLES.h>
+#define MGITEST_PIPE_APPLY_PEEK_LIVE 1
+#endif
+#endif
+
+namespace MGITest {
+
+#if defined(MGITEST_PIPE_APPLY_PEEK_LIVE)
+    namespace {
+        namespace MGP = MobileGL::MG_Pipe;
+        namespace MGB = MobileGL::MG_Backend::DirectGLES;
+
+        // The frontend texture object a GL name denotes in the CURRENT context, or null. This is
+        // a LOOKUP KEY and nothing else: every value this file reports comes from the applier or
+        // from Espryt, never from the object found here. (Reading the frontend's own parameter
+        // state would answer the question the scenario is asking with the input to it.)
+        MobileGL::MG_State::GLState::ITextureObject* FrontendTexture(unsigned glTextureName) {
+            if (!MobileGL::MG_State::pGLContext) return nullptr;
+            const auto& object = MobileGL::MG_State::pGLContext->GetTextureObject(
+                static_cast<MobileGL::Uint>(glTextureName));
+            return object ? object.get() : nullptr;
+        }
+
+        // Espryt's twin for that texture, or null - which is also this file's "is Espryt even the
+        // backend running" answer. On Magma no Espryt twin was ever built, so every entry point
+        // below stops here rather than reaching for g_GLESFuncs, whose members are null there.
+        MGB::TextureImpl::BackendTextureObject* EsprytTwin(unsigned glTextureName) {
+            MobileGL::MG_State::GLState::ITextureObject* const object = FrontendTexture(glTextureName);
+            if (object == nullptr) return nullptr;
+            auto* const found = MGB::TextureImpl::g_backendTextureObjects.Find(object);
+            if (found == nullptr || !*found) return nullptr;
+            return found->get();
+        }
+
+        int SwizzleToGLEnum(MobileGL::Uint8 encoded) {
+            return static_cast<int>(MobileGL::MG_Util::ConvertTextureSwizzleParamToGLEnum(
+                static_cast<MobileGL::TextureSwizzleParam>(encoded)));
+        }
+
+        // MGPipeTypes.h owns the two numbers and says why depth is 0 (a zeroed record must decode
+        // to what an untouched texture already has). This is that decode, and nothing else in
+        // this module may open-code it.
+        int DepthStencilModeToGLEnum(MobileGL::Uint8 encoded) {
+            return encoded == MGP::kMGPipeDepthStencilModeStencil ? GL_STENCIL_INDEX
+                                                                  : GL_DEPTH_COMPONENT;
+        }
+
+        // The GL_TEXTURE_BINDING_* query for a target, or 0 where this file has no answer. A
+        // guess would be worse than a refusal: the binding is what gets RESTORED, so a wrong
+        // pname would leave the driver bound to this test's texture.
+        int BindingQueryFor(unsigned glTarget) {
+            switch (glTarget) {
+                case GL_TEXTURE_2D: return GL_TEXTURE_BINDING_2D;
+                default: return 0;
+            }
+        }
+    } // namespace
+
+    bool PeekPipeTextureParamsRecord(unsigned glTextureName, PipeTextureParamsRecordPeek* out) {
+        if (out == nullptr) return false;
+        const MGP::MGPipeApplierState& applier = MGP::MGPipeApplier();
+        // Slot 0 is the reserved null handle and is never live (MGPipeHandles.h), so the scan
+        // starts at 1 and a match at 0 is impossible rather than merely unlikely.
+        for (MobileGL::SizeT slot = 1; slot < applier.TextureResources.size(); ++slot) {
+            const MGP::MGPipeResourceRecord& record = applier.TextureResources[slot];
+            if (!record.Live) continue;
+            if (record.Desc.GlNameForDiag != static_cast<MobileGL::Uint32>(glTextureName)) continue;
+            out->Slot = static_cast<unsigned>(slot);
+            out->Gen = static_cast<unsigned>(record.Gen);
+            out->ParamsSerial = static_cast<unsigned long long>(record.ParamsSerial);
+            for (int channel = 0; channel < 4; ++channel) {
+                out->Swizzle[channel] = SwizzleToGLEnum(record.Params.Swizzle[channel]);
+            }
+            out->DepthStencilMode = DepthStencilModeToGLEnum(record.Params.DepthStencilMode);
+            return true;
+        }
+        return false;
+    }
+
+    bool PeekEsprytAppliedTextureParams(unsigned glTextureName, unsigned glTarget,
+                                        EsprytAppliedTextureParamsPeek* out) {
+        if (out == nullptr) return false;
+        const int bindingQuery = BindingQueryFor(glTarget);
+        if (bindingQuery == 0) return false;
+        MGB::TextureImpl::BackendTextureObject* const twin = EsprytTwin(glTextureName);
+        if (twin == nullptr) return false;
+        const MobileGL::Uint backendId = twin->GetBackendTextureId();
+        if (backendId == 0) return false;
+        if (MGB::g_GLESFuncs.glGetTexParameteriv == nullptr ||
+            MGB::g_GLESFuncs.glBindTexture == nullptr || MGB::g_GLESFuncs.glGetIntegerv == nullptr ||
+            MGB::g_GLESFuncs.glGetError == nullptr) {
+            return false;
+        }
+
+        // SAVE / QUERY / RESTORE ON THE UNIT THAT IS ALREADY ACTIVE. No glActiveTexture, so the
+        // only driver state this touches is one unit's binding, and it is put back byte for byte
+        // - which is what keeps Espryt's own g_boundTexturesCache true rather than merely
+        // consistent. (Binding through the twin's own Bind() would update that shadow and would
+        // therefore CHANGE what the scenario measures next; this does not.)
+        GLint previousBinding = 0;
+        MGB::g_GLESFuncs.glGetIntegerv(static_cast<GLenum>(bindingQuery), &previousBinding);
+        MGB::g_GLESFuncs.glBindTexture(static_cast<GLenum>(glTarget), backendId);
+
+        out->BackendTextureId = static_cast<unsigned>(backendId);
+        static const GLenum kSwizzlePnames[4] = {GL_TEXTURE_SWIZZLE_R, GL_TEXTURE_SWIZZLE_G,
+                                                 GL_TEXTURE_SWIZZLE_B, GL_TEXTURE_SWIZZLE_A};
+        for (int channel = 0; channel < 4; ++channel) {
+            GLint value = 0;
+            MGB::g_GLESFuncs.glGetTexParameteriv(static_cast<GLenum>(glTarget),
+                                                 kSwizzlePnames[channel], &value);
+            out->Swizzle[channel] = static_cast<int>(value);
+        }
+
+        // The depth/stencil aspect mode is ES 3.1 and is INVALID_ENUM on a driver without it, so
+        // it is asked for last and its own error decides whether the answer is usable. The queue
+        // is drained first because a stale error from anywhere else would be indistinguishable
+        // from this call's - Espryt drains it the same way at every one of its own sync sites
+        // (DebugImpl::ErrorLopper), and this module's own GL errors are read from the FRONTEND
+        // state (ScenarioTest::FirstGLError), which none of this touches.
+        while (MGB::g_GLESFuncs.glGetError() != GL_NO_ERROR) {
+        }
+        GLint mode = 0;
+        MGB::g_GLESFuncs.glGetTexParameteriv(static_cast<GLenum>(glTarget),
+                                             GL_DEPTH_STENCIL_TEXTURE_MODE, &mode);
+        out->DepthStencilModeIsReadable = MGB::g_GLESFuncs.glGetError() == GL_NO_ERROR;
+        out->DepthStencilMode = static_cast<int>(mode);
+
+        MGB::g_GLESFuncs.glBindTexture(static_cast<GLenum>(glTarget),
+                                       static_cast<GLuint>(previousBinding));
+        while (MGB::g_GLESFuncs.glGetError() != GL_NO_ERROR) {
+        }
+        return true;
+    }
+
+    bool PeekEsprytHasSamplerViewForTexture(unsigned glTextureName, bool* outExists) {
+        if (outExists == nullptr) return false;
+        MobileGL::MG_State::GLState::ITextureObject* const object = FrontendTexture(glTextureName);
+        if (object == nullptr) return false;
+        // Espryt must be the backend running, or "no view" would be true of every texture on
+        // every other backend and the assertion would be vacuous where it is loudest.
+        if (EsprytTwin(glTextureName) == nullptr) return false;
+        // HandleOfSamplerViewForTexture is the monolith glue that derives the view's handle from
+        // the TEXTURE's lifetime id (D-F2: one view per ITextureObject), so this asks Espryt's
+        // own table the same way Espryt asks it - it does not consult the applier record's
+        // ViewCso, which is the client's statement about the same fact and would make one side
+        // of the seam vouch for the other.
+        const MGP::MGPipeHandle view = MGB::SamplerViewImpl::HandleOfSamplerViewForTexture(object);
+        if (MGP::MGPipeHandleIsNull(view)) {
+            *outExists = false;
+            return true;
+        }
+        *outExists = MGB::SamplerViewImpl::FindSamplerViewForHandle(view) != nullptr;
+        return true;
+    }
+
+    bool PeekPipeApplierRefusedNoConsumer(unsigned long long* outCount) {
+        if (outCount == nullptr) return false;
+        *outCount = static_cast<unsigned long long>(MGP::MGPipeApplier().RefusedNoConsumer);
+        return true;
+    }
+#else
+    bool PeekPipeTextureParamsRecord(unsigned, PipeTextureParamsRecordPeek*) { return false; }
+    bool PeekEsprytAppliedTextureParams(unsigned, unsigned, EsprytAppliedTextureParamsPeek*) {
+        return false;
+    }
+    bool PeekEsprytHasSamplerViewForTexture(unsigned, bool*) { return false; }
+    bool PeekPipeApplierRefusedNoConsumer(unsigned long long*) { return false; }
+#endif
+
+} // namespace MGITest

MobileGL/MG_IntegrationTest/Harness/PipeApplyPeek.h

@@ -0,0 +1,110 @@
+// MobileGL - MobileGL/MG_IntegrationTest/Harness/PipeApplyPeek.h
+// Copyright (c) 2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+//
+// The APPLIER's texture-parameter record, ESPRYT's applied value for the same texture, and
+// whether that texture has a sampler view yet. Three readings taken from a scenario, for gate
+// G9's WHITE-BOX half.
+//
+// WHY A WHITE-BOX HALF EXISTS AT ALL (ID-19, brief section F, gates review R1). G9's public-GL
+// cases in TextureParamsWithoutASamplerViewScenario.cpp catch "the parameter never reached the
+// driver". They CANNOT catch "the parameter reached the driver LATE", because a texture
+// parameter's only public-GL observable is a SAMPLE and the sample is itself what repairs an
+// unsynced parameter: it puts the texture on the unit list, and that walk pushes the parameters
+// for anything whose params serial moved. A backend that deferred every attachment-only
+// texture's parameters to the first sampler view would be green on all four of those cases,
+// forever, on every tree. The distinction only exists on the inside, so the reading has to be
+// taken there - while the texture is still attachment-only, before any sample.
+//
+// A SEPARATE TRANSLATION UNIT for PipeSlotPeek.h's reason, verbatim: the scenario sources
+// include the GL headers with prototypes and MobileGL's umbrella header is not meant to meet
+// them in one file. This one goes further than PipeSlotPeek and includes Espryt's own
+// Managers.h, which is exactly why it may not be anywhere near a scenario's GL headers.
+//
+// EVERY ENTRY POINT RETURNS false, TOUCHING NOTHING, WHERE IT CANNOT LOOK, and a caller that
+// gets false has learned NOTHING - "could not look" is not "was applied". Out of reach means:
+// a PULL build (there is no applier: it is `#if MOBILEGL_PIPE_PUSH`); Android, where this module
+// links the shipping libMobileGL.so built -fvisibility=hidden and no internal symbol resolves;
+// a backend that is not DirectGLES (Espryt is the subject; Magma answers the same GL question
+// through P7's own paths); and, for the record peek, a mask whose texture-resource bit is off,
+// where no record exists to find because nothing was ever emitted.
+
+#pragma once
+
+namespace MGITest {
+
+    // ---- the applier's set_texture_params record for one GL texture name ------------------
+    //
+    // ADDRESSED BY GL NAME, and the search key is MGPResourceDesc::GlNameForDiag. That field is
+    // diagnostics-only by contract - never an identity, never a memo key (MGPipeTypes.h) - and
+    // this is a diagnostic: a test harness looking for the record a named GL object produced.
+    // The alternative would be to ask the CLIENT emitter for the texture's handle, and the
+    // review is explicit that this probe must arm on package D's applier/backend state and not
+    // on the emitter markers B and C set: they are different questions, and a shared marker
+    // would re-create the shape review F-M5 was raised about.
+    struct PipeTextureParamsRecordPeek {
+        // The handle the record sits at, so a caller can print it.
+        unsigned Slot;
+        unsigned Gen;
+        // set_texture_params' own serial. 0 means the record exists (the resource was created)
+        // but NO set_texture_params has ever been applied to it - which is a different finding
+        // from "no record", and the two must not be merged.
+        unsigned long long ParamsSerial;
+        // MGPTextureParams::Swizzle[4], translated to the GL enums the application passed to
+        // glTextureParameteri (GL_ZERO / GL_ONE / GL_RED / GL_GREEN / GL_BLUE / GL_ALPHA), so
+        // the scenario compares what it set against what the record carries in ONE vocabulary
+        // and neither side has to know the other's encoding.
+        int Swizzle[4];
+        // MGPTextureParams::DepthStencilMode, translated the same way: GL_DEPTH_COMPONENT or
+        // GL_STENCIL_INDEX.
+        int DepthStencilMode;
+    };
+
+    bool PeekPipeTextureParamsRecord(unsigned glTextureName, PipeTextureParamsRecordPeek* out);
+
+    // ---- Espryt's APPLIED value for the same texture --------------------------------------
+    //
+    // Read from the DRIVER, through the twin's own ES name, because "applied" means the driver
+    // was told - the same thing package D's white-box unit probe asserts against its mocked
+    // driver (esprytobj-v2 (9)). The current binding on the ACTIVE unit is saved and restored
+    // around the query and no unit is switched, so Espryt's binding shadow still describes
+    // reality afterwards: nothing is perturbed for it to be stale about.
+    //
+    // `glTarget` is the texture's GL target (only GL_TEXTURE_2D is supported today; any other
+    // target returns false rather than guessing a binding query).
+    struct EsprytAppliedTextureParamsPeek {
+        // The driver name Espryt minted for this texture, for the caller's message.
+        unsigned BackendTextureId;
+        int Swizzle[4];
+        int DepthStencilMode;
+        // False when the driver rejected the depth/stencil query - a non-depth texture, or an ES
+        // level without GL_DEPTH_STENCIL_TEXTURE_MODE. The swizzle half is still valid.
+        bool DepthStencilModeIsReadable;
+    };
+
+    bool PeekEsprytAppliedTextureParams(unsigned glTextureName, unsigned glTarget,
+                                        EsprytAppliedTextureParamsPeek* out);
+
+    // ---- and the claim that makes the two above mean anything ------------------------------
+    //
+    // Whether Espryt holds a SAMPLER VIEW twin for this texture. This is the assertion the
+    // public-GL cases cannot make, because making it there would create the view. `*outExists`
+    // is written only on true.
+    bool PeekEsprytHasSamplerViewForTexture(unsigned glTextureName, bool* outExists);
+
+    // ---- c0f's belt, for the ObjectSubsystemControl arms -----------------------------------
+    //
+    // MGPipeApplierState::RefusedNoConsumer: the number of P4a-family entry points that were
+    // refused because no backend had registered MGPipeResourceOps. On a backend WITH a consumer
+    // it must never move; on one without (Magma, ID-39/ID-40) the client's own gate is supposed
+    // to stop the emission before the belt is reached, so it must never move there either. A
+    // non-zero delta says the gate and the belt disagreed, which is the whole point of having
+    // both. Reset by MGPipeApplierReset, so a caller reads it as a DELTA and treats a value that
+    // went DOWN as "the applier was reset, count everything since as `after`".
+    bool PeekPipeApplierRefusedNoConsumer(unsigned long long* outCount);
+
+} // namespace MGITest

MobileGL/MG_IntegrationTest/Harness/PipeSlotPeek.cpp

@@ -20,11 +20,24 @@ namespace MGITest {
 
 #if defined(MGITEST_PIPE_SLOT_PEEK_LIVE)
     namespace {
+        // One arm per member, and NO `default:` on purpose: adding a PipeSlotKind without
+        // deciding which MGPipeKind it names is a compiler warning here (-Wswitch) rather than
+        // a row that silently counts VertexElementsCso and reports "did not leak" about a kind
+        // it never looked at. The trailing return is the unreachable one the compiler needs.
         MobileGL::MG_Pipe::MGPipeKind Translate(PipeSlotKind kind) {
             switch (kind) {
                 case PipeSlotKind::Buffer: return MobileGL::MG_Pipe::MGPipeKind::Buffer;
-                default: return MobileGL::MG_Pipe::MGPipeKind::VertexElementsCso;
+                case PipeSlotKind::VertexElementsCso:
+                    return MobileGL::MG_Pipe::MGPipeKind::VertexElementsCso;
+                case PipeSlotKind::Texture: return MobileGL::MG_Pipe::MGPipeKind::Texture;
+                case PipeSlotKind::Renderbuffer: return MobileGL::MG_Pipe::MGPipeKind::Renderbuffer;
+                case PipeSlotKind::Framebuffer: return MobileGL::MG_Pipe::MGPipeKind::Framebuffer;
+                case PipeSlotKind::SamplerCso: return MobileGL::MG_Pipe::MGPipeKind::SamplerCso;
+                case PipeSlotKind::SamplerViewCso:
+                    return MobileGL::MG_Pipe::MGPipeKind::SamplerViewCso;
+                case PipeSlotKind::ShaderCso: return MobileGL::MG_Pipe::MGPipeKind::ShaderCso;
             }
+            return MobileGL::MG_Pipe::MGPipeKind::None;
         }
     } // namespace
 
@@ -36,12 +49,34 @@ namespace MGITest {
 
     bool PeekPipeSlotHighWater(PipeSlotKind kind, unsigned* outHighWater) {
         if (outHighWater == nullptr) return false;
+        // The ORDINARY space only, for every kind including ShaderCso (contract-v2.md 4.3).
         *outHighWater = static_cast<unsigned>(MobileGL::MG_Pipe::MGPipeSlots().HighWater(Translate(kind)));
         return true;
     }
+
+    bool PeekPipeCompositeSlotLiveCount(unsigned* outLive) {
+        if (outLive == nullptr) return false;
+        *outLive = static_cast<unsigned>(MobileGL::MG_Pipe::MGPipeSlots().CompositeLiveCount());
+        return true;
+    }
+
+    bool PeekPipeCompositeSlotHighWater(unsigned* outHighWater) {
+        if (outHighWater == nullptr) return false;
+        *outHighWater = static_cast<unsigned>(MobileGL::MG_Pipe::MGPipeSlots().CompositeHighWater());
+        return true;
+    }
+
+    bool PeekPipeCompositeSlotBandBase(unsigned* outBandBase) {
+        if (outBandBase == nullptr) return false;
+        *outBandBase = static_cast<unsigned>(MobileGL::MG_Pipe::kMGPipeShaderCsoCompositeSlotBase);
+        return true;
+    }
 #else
     bool PeekPipeSlotLiveCount(PipeSlotKind, unsigned*) { return false; }
     bool PeekPipeSlotHighWater(PipeSlotKind, unsigned*) { return false; }
+    bool PeekPipeCompositeSlotLiveCount(unsigned*) { return false; }
+    bool PeekPipeCompositeSlotHighWater(unsigned*) { return false; }
+    bool PeekPipeCompositeSlotBandBase(unsigned*) { return false; }
 #endif
 
 } // namespace MGITest

MobileGL/MG_IntegrationTest/Harness/PipeSlotPeek.h

@@ -30,6 +30,36 @@ namespace MGITest {
     enum class PipeSlotKind {
         Buffer,
         VertexElementsCso,
+        // P4a's six (G8b). Every one of them is a kind the CLIENT mints and the client alone
+        // frees (BRIEF-P4A.md D-I1: one death helper per kind, called from the frontend
+        // object's own destructor, whatever backend is running), so every one of them can leak
+        // the P3a C-1 way - and the leak is invisible in pixels, in GL names and in
+        // glGetError, exactly as the VertexElementsCso one was.
+        Texture,
+        Renderbuffer,
+        // Framebuffer has a HANDLE but no wire lifetime (D-I2): no create_*, no destroy row in
+        // the catalogue, and its death helper does the notice and the free and emits nothing.
+        // That makes the allocator the ONLY observable of its lifetime, so this row matters
+        // more here than the others rather than less.
+        Framebuffer,
+        SamplerCso,
+        SamplerViewCso,
+        // ShaderCso covers BOTH the ordinary program slots and the program-pipeline COMPOSITES
+        // minted out of the reserved high band (MGPipeHandles.h:86-107, D-H7). One kind, because
+        // that is what the allocator has: the band is a second dense table inside the same kind
+        // and LiveCount counts both.
+        //
+        // THE TWO SPACES' HIGH-WATER MARKS ARE NOT ONE NUMBER, and the correction matters here
+        // more than anywhere else. c0b split them (contract-v2.md 4.3): HighWater(ShaderCso) is
+        // now the ORDINARY space only and the band's own mark is CompositeHighWater(), because
+        // a merged mark is pinned at ~983k from the first composite mint onward and every "the
+        // high-water mark did not move over N churn rounds" assertion about ordinary programs
+        // would be vacuously true for the rest of the process. The composite's leak case is a
+        // separate CASE and reads the BAND'S OWN counters below (PeekPipeCompositeSlot*) - a
+        // composite's slot has TWO independent release paths (the pipeline cache's LRU eviction
+        // and the composite ProgramObject's destructor), and a slot that never comes back to
+        // the band moves neither of the ordinary numbers.
+        ShaderCso,
     };
 
     // Live slots of this kind right now, and one past the highest slot ever handed out.
@@ -41,4 +71,31 @@ namespace MGITest {
     bool PeekPipeSlotLiveCount(PipeSlotKind kind, unsigned* outLive);
     bool PeekPipeSlotHighWater(PipeSlotKind kind, unsigned* outHighWater);
 
+    // The ShaderCso COMPOSITE BAND's own three numbers, the seventh..ninth members
+    // contract-v2.md 4.3 asks this header for. There is no `kind` argument because the band is
+    // ShaderCso's alone - AllocateComposite is the one door into it and no other kind has one.
+    // All three return false on the same terms as the two above, and a caller that gets false
+    // must SKIP.
+    //
+    //   PeekPipeCompositeSlotLiveCount   = MGPipeSlotAllocator::CompositeLiveCount(), the band's
+    //                                      share of LiveCount(ShaderCso).
+    //   PeekPipeCompositeSlotHighWater   = CompositeHighWater() VERBATIM, i.e. one past the
+    //                                      highest band slot ever handed out. It is an ABSOLUTE
+    //                                      slot number and therefore starts at the band's base,
+    //                                      not at zero - "no composite was ever minted" reads as
+    //                                      `high water == band base`, which is what the third
+    //                                      member is for. It is not returned base-relative
+    //                                      because a peek whose name says HighWater and whose
+    //                                      value is a delta is exactly the kind of quietly
+    //                                      redefined counter this member exists to correct.
+    //   PeekPipeCompositeSlotBandBase    = kMGPipeShaderCsoCompositeSlotBase, the floor the
+    //                                      other two are read against. A constant, but it
+    //                                      reaches a scenario only through this header: the
+    //                                      MG_Pipe headers and the GL headers are not meant to
+    //                                      meet in one translation unit, which is why this
+    //                                      harness exists at all.
+    bool PeekPipeCompositeSlotLiveCount(unsigned* outLive);
+    bool PeekPipeCompositeSlotHighWater(unsigned* outHighWater);
+    bool PeekPipeCompositeSlotBandBase(unsigned* outBandBase);
+
 } // namespace MGITest

MobileGL/MG_IntegrationTest/Scenarios/ObjectSubsystemControlScenario.cpp

@@ -0,0 +1,878 @@
+// MobileGL - MobileGL/MG_IntegrationTest/Scenarios/ObjectSubsystemControlScenario.cpp
+// Copyright (c) 2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+//
+// Scenario - THE P4a SUBSYSTEM A/B IS REAL, AND ITS DEPENDENCY REFUSALS ARE EXERCISED (gate G12).
+//
+// P4a migrates FOUR subsystems (D-K1, MG_Pipe/MGPipe.h):
+//
+//   bit  9  kMGPipeSubsystemFramebuffer       set_framebuffer_state
+//   bit 10  kMGPipeSubsystemTextureResources  texture + renderbuffer resource_*, set_texture_params
+//   bit 11  kMGPipeSubsystemSamplers          sampler CSO, sampler view, the three unit sets
+//   bit 12  kMGPipeSubsystemPrograms          shader CSO, draw/dispatch program, global constants
+//
+// so the push build's default mask becomes kMGPipeSubsystemsMigratedAtP4a = 0x1fff, and P3a's
+// 0x1ff survives as the control that clears exactly those four - MGPipe.h's rule that every phase's
+// constant keeps meaning what it meant, so an operator's recorded mask is still readable a phase
+// later. THE OFF LANE IS 0x1ff AND NOT A HAND-PICKED PATTERN, for that reason.
+//
+// That A/B is what every "push vs pull" number in MEASUREMENTS.md is taken against, and it has one
+// characteristic failure mode: the bits stop steering anything, both arms run the same code, and
+// every later comparison is quietly taken against a switch that does nothing. This file is the
+// entry that cannot let that happen. It is the P4a analogue of ResourceSubsystemControlScenario and
+// deliberately its twin in shape.
+//
+// WHAT IT ASSERTS, per lane:
+//
+//   on  (MOBILEGL_PIPE_PUSH=0x1fff)
+//       The client emits P4a's records for the workload: a framebuffer state per bound target that
+//       moved, the three unit sets, and the client-side texture upload record. The window's
+//       emit[fbe= sve= sse= sie= ctu=] bracket therefore carries a NON-ZERO total.
+//
+//   off (MOBILEGL_PIPE_PUSH=0x1ff, P3a's default = P4a's four subsystems cleared)
+//       The frontend dispatch falls through to the legacy MGB_CTX-reading arms, nothing is emitted
+//       through any of the four families, and every one of those five counters must read ZERO.
+//       This is the reading a dead switch fails: with the bits ignored, this lane would report the
+//       same non-zero counts as the other one.
+//
+//   refused (MOBILEGL_PIPE_PUSH=0x9ff = bits 0..8 plus bit 11, samplers, WITHOUT bit 10)
+//       D-K2's dependency refusal. Every MGPBoundView::Texture and MGPImageView::Res names a
+//       Texture handle and only bit 10 populates the texture slot table, so a sampler subsystem
+//       without it would miss every lookup and walk on without unbinding. The bring-up logs ONE
+//       error naming BOTH bits, refuses bit 11 and runs the legacy sampler arm - modelled on the
+//       bit-8-requires-bit-7 refusal that already ships (Managers.cpp:2393-2410). The assertion is
+//       that the refusal is NAMED and that the run then produces the same pixels as any other
+//       lane: a refusal that half-ran, or that aborted, would both be failures here.
+//
+//   refused-texture (MOBILEGL_PIPE_PUSH=0x5ff = bits 0..8 plus bit 10, texture resources, WITHOUT
+//       bit 11)
+//       D-K2's FOURTH row (ID-15), and the direction the brief originally called harmless.
+//       MGPTextureParams::BuiltinSampler is a SamplerCso HANDLE and only bit 11 mints sampler
+//       CSOs, so with bit 10 alone every set_texture_params would carry a null there and the
+//       applier's Fatal{ProtocolCorruption} is the next thing that happens. Same two assertions
+//       as the lane above, with the two bits' roles swapped.
+//
+//   both refusal lanes
+//       "NAMED" means ONE LINE of the library's log, at ERROR severity, that says it REFUSED and
+//       names both bits. Not a substring anywhere in the file: the word "sampler" appears in
+//       almost any log the sampler path writes to, and an assertion that cannot go red for its
+//       stated reason is worse than no assertion (review F-M6).
+//
+//   every lane
+//       THE PIXELS MUST NOT MOVE. The workload draws one solid-colour quad through a texture, an
+//       explicit sampler object and a user framebuffer, and every lane must read back that colour.
+//       "The counters moved and the picture did not" is the whole claim - a switch that changed
+//       what is drawn would not be an A/B, it would be a bug.
+//
+// WHY IT CAN SKIP. The counters are emitted by the client-side emitters P4a packages B and C own,
+// and this file is written against the P4a contract commit, before either lands. Until then nothing
+// emits, the five counters are structurally zero in BOTH lanes, and an assertion about the
+// difference would be a statement about nothing. The build answers the question rather than a
+// hand-maintained list: MG_IntegrationTest/CMakeLists.txt greps every source under MG_Impl/Pipe/
+// for the counters' names and passes the answer in as MGITEST_PIPE_OBJECT_EMITTER_PRESENT, with a
+// CONFIGURE_DEPENDS on that directory and on each file it finds so the answer cannot go stale. It
+// is a CONTENT probe, not a filename probe, so the owning packages keep control of their own file
+// layout - P4a's new client files are headers (D-P), and a glob for a named .cpp would have kept
+// this control skipping forever with a reason that had become false.
+//
+// DIRECTGLES ONLY, and that is the honest scope: P4a migrates Espryt's framebuffer, texture,
+// sampler and program paths. Magma's are P7 (D-Q) and register nothing here, so a DirectVulkan lane
+// would be measuring the client emitters against a backend nobody asked to change.
+
+#include <cstdint>
+#include <cstdlib>
+#include <cstring>
+#include <iostream>
+#include <string>
+#include <vector>
+
+#include "../Harness/HeadlessGL.h"
+#include "../Harness/PipeApplyPeek.h"
+#include "../Harness/PipeStatsWindow.h"
+#include "../Harness/ScenarioFixture.h"
+
+#ifdef GLAPI
+#undef GLAPI
+#endif
+#define GL_GLEXT_PROTOTYPES
+#include <GL/gl.h>
+#include <GL/glcorearb.h>
+#undef GL_GLEXT_PROTOTYPES
+
+namespace MGITest {
+    namespace {
+
+        // Set by the three ObjectSubsystemControl. ctest entries and by nothing else; a harness
+        // marker, never read by the library. Its absence means an ambient entry, where neither the
+        // stats channel nor a private log path is configured.
+        constexpr const char* kLaneMarker = "MGITEST_OBJECT_SUBSYSTEM_LANE";
+        constexpr const char* kLaneOn = "on";
+        constexpr const char* kLaneOff = "off";
+        constexpr const char* kLaneRefused = "refused";
+        // D-K2's FOURTH row (ID-15): bit 10 without bit 11. 0x5ff is 0x1ff plus bit 10.
+        constexpr const char* kLaneRefusedTexture = "refused-texture";
+        // c0f's two halves (ID-39/ID-40), run at the phase default on BOTH backends: the client
+        // GATE (a P4a family emits only where a backend registered MGPipeResourceOps) and the
+        // applier's BELT (every P4a entry point refuses and counts RefusedNoConsumer when none
+        // did). One lane per backend, because the interesting one is the backend with NO
+        // consumer - Magma - and the other is the control that says the assertion is not
+        // vacuously true of a tree where nothing emits at all.
+        constexpr const char* kLaneConsumer = "consumer";
+        constexpr const char* kLaneNoConsumer = "no-consumer";
+
+        bool LaneIsARefusalLane(const std::string& lane) {
+            return lane == kLaneRefused || lane == kLaneRefusedTexture;
+        }
+
+        bool LaneIsAConsumerLane(const std::string& lane) {
+            return lane == kLaneConsumer || lane == kLaneNoConsumer;
+        }
+
+        constexpr int kInset = 2;
+        constexpr int kTextureSize = 4;
+        // Enough frames that a per-frame emitter and a per-draw emitter read differently, and few
+        // enough that one summary window covers exactly this.
+        constexpr int kDrawsInTheWindow = 4;
+
+        constexpr const char* kVS = R"(#version 330 core
+in vec2 aPos;
+out vec2 vUv;
+void main() {
+    vUv = aPos * 0.5 + 0.5;
+    gl_Position = vec4(aPos, 0.0, 1.0);
+}
+)";
+
+        constexpr const char* kFS = R"(#version 330 core
+in vec2 vUv;
+uniform sampler2D uTex;
+out vec4 oColor;
+void main() { oColor = texture(uTex, vUv); }
+)";
+
+        struct Vertex {
+            float x, y;
+        };
+
+        bool BuildMarkerIsSet(const char* name) {
+            const char* value = std::getenv(name);
+            return value != nullptr && value[0] == '1' && value[1] == '\0';
+        }
+
+        std::string LaneName() {
+            const char* lane = std::getenv(kLaneMarker);
+            return lane != nullptr ? std::string(lane) : std::string();
+        }
+
+        // ---- reading the refusal out of the library's own log ------------------------------
+        //
+        // THE UNIT IS A LINE, AND THE LINE HAS TO BE THE REFUSAL (review F-M6). The first cut of
+        // this asked whether the WHOLE FILE contained a lowercase "sampler" and whether it
+        // contained "texture resource", anywhere, in any order, at any severity. Both are true of
+        // almost any log the moment the sampler path says anything at all, so the assertion could
+        // not go red for the reason it claims and the one P4a control that is not vacuous before
+        // the emitters land would have been vacuous too.
+        //
+        // What is matched instead is one line that is ALL of:
+        //   * at ERROR severity - the library writes "[<time>] [<os> <thread>/<TAG>]: <message>",
+        //     one record per line (MG_Util/Debug/Log.cpp), and D-K2 asks for an MGLOG_E. A refusal
+        //     that was demoted to a D or a W is a refusal an operator's log will not carry;
+        //   * carrying the helper's own decision clause, verbatim - so a line that merely
+        //     mentions the two bits (a future summary, a comment echoed into the log) is not
+        //     mistaken for the decision;
+        //   * naming the bit that was SET and the bit it NEEDED, on that same line, AND IN THAT
+        //     ORDER - see the direction check below.
+        //
+        // Espryt's text is one MGLOG_E from the helper the three dependent families share
+        // (Managers.cpp, PipeSubsystemDependencyMissing): "MGPipe: <A> (bit N) is set but <B>
+        // (bit M) is clear; <why> - REFUSING the dependent bit and running the legacy arm. Set
+        // both bits, or clear both". Three spellings are accepted per bit - the constant's name,
+        // "(bit N)", and the hexadecimal mask - so the assertion pins the DECISION and the
+        // DIRECTION, and not the family-specific prose in <why>.
+        //
+        // THE DIRECTION IS THE HALF THIS FILE USED TO BE MISSING (review F-v2-m1). The first form
+        // of the matcher asked "does the line name bit A?" AND "does the line name bit B?", which
+        // is a SYMMETRIC conjunction: swapping the two arguments - exactly what separates the
+        // 0x5ff case from the 0x9ff one below, and what each of their comments claims to be
+        // doing - could not change the answer, and both cases went green on either line. A
+        // resolver that refused correctly but printed the MIRROR sentence would have been green
+        // on a refusal that told the operator the wrong dependency, which is the same class of
+        // "the log says something plausible" defect that made the whole-file substring search
+        // (F-M6) worthless one level up. The two resolvers are forty lines apart in one file,
+        // share this helper and differ only in the `what` string, so the copy-paste is one edit
+        // away at all times.
+        //
+        // What makes the direction readable is the sentence's own shape: the SET bit is named
+        // before " is set but " and the NEEDED bit between that and " is clear". So the check is
+        // four offsets in strictly increasing order, and it is the sentence Espryt emits rather
+        // than a re-statement of it.
+        constexpr const char* kSaysItRefused = "REFUSING the dependent bit and running the legacy arm";
+        constexpr const char* kSaysWhichIsSet = " is set but ";
+        constexpr const char* kSaysWhichIsClear = " is clear";
+
+        // The earliest offset at which any accepted spelling of one bit appears, or npos. The
+        // EARLIEST rather than any: a spelling that also occurs later in <why> (Espryt's
+        // bit-10-requires-bit-11 sentence says "only bit 11 mints sampler CSOs" in its reason)
+        // must not be able to satisfy an ordering the first occurrence does not.
+        std::size_t EarliestSpellingOffset(const std::string& line,
+                                           const std::vector<std::string>& spellings) {
+            std::size_t earliest = std::string::npos;
+            for (const std::string& spelling : spellings) {
+                const std::size_t at = line.find(spelling);
+                if (at != std::string::npos && (earliest == std::string::npos || at < earliest)) {
+                    earliest = at;
+                }
+            }
+            return earliest;
+        }
+
+        // The matching line, or an empty string. Returned rather than a bool so the case can print
+        // what it found: a reader of a green refusal lane must be able to see the sentence.
+        std::string FindTheRefusalLine(const std::string& log,
+                                       const std::vector<std::string>& bitThatWasSet,
+                                       const std::vector<std::string>& bitThatWasNeeded) {
+            std::size_t pos = 0;
+            while (pos <= log.size()) {
+                const std::size_t newline = log.find('\n', pos);
+                const std::string line = log.substr(
+                    pos, newline == std::string::npos ? std::string::npos : newline - pos);
+                const bool atErrorSeverity = line.find("/ERROR]") != std::string::npos;
+                const std::size_t refusedAt = line.find(kSaysItRefused);
+                const std::size_t setAt = EarliestSpellingOffset(line, bitThatWasSet);
+                const std::size_t setClauseAt = line.find(kSaysWhichIsSet);
+                const std::size_t neededAt = EarliestSpellingOffset(line, bitThatWasNeeded);
+                const std::size_t clearClauseAt = line.find(kSaysWhichIsClear);
+                const bool everyPartIsThere =
+                    refusedAt != std::string::npos && setAt != std::string::npos &&
+                    setClauseAt != std::string::npos && neededAt != std::string::npos &&
+                    clearClauseAt != std::string::npos;
+                // "<set bit> ... is set but ... <needed bit> ... is clear", strictly in that
+                // order. Swapping the caller's two arguments breaks the chain, which is the
+                // whole of F-v2-m1.
+                const bool inTheRightDirection =
+                    everyPartIsThere && setAt < setClauseAt && setClauseAt < neededAt &&
+                    neededAt < clearClauseAt;
+                if (atErrorSeverity && inTheRightDirection) {
+                    return line;
+                }
+                if (newline == std::string::npos) break;
+                pos = newline + 1;
+            }
+            return std::string();
+        }
+
+        // The three accepted spellings of each of the two P4a bits this file's two refusal lanes
+        // are about. MGPipe.h: bit 10 = kMGPipeSubsystemTextureResources = 0x400,
+        // bit 11 = kMGPipeSubsystemSamplers = 0x800.
+        std::vector<std::string> SamplerBitSpellings() {
+            return {"kMGPipeSubsystemSamplers", "(bit 11)", "0x800"};
+        }
+
+        std::vector<std::string> TextureResourceBitSpellings() {
+            return {"kMGPipeSubsystemTextureResources", "(bit 10)", "0x400"};
+        }
+
+        class ObjectSubsystemControlScenario : public ScenarioTest {
+        protected:
+            void SetUp() override {
+                ScenarioTest::SetUp();
+                if (!Ready()) return;
+                m_lane = LaneName();
+                std::string error;
+                m_program = CompileProgram(kVS, kFS, &error);
+                ASSERT_NE(m_program, 0u) << error;
+
+                static const Vertex quad[6] = {{-1.0f, -1.0f}, {1.0f, -1.0f}, {1.0f, 1.0f},
+                                               {-1.0f, -1.0f}, {1.0f, 1.0f},  {-1.0f, 1.0f}};
+                glGenBuffers(1, &m_quadBuffer);
+                glBindBuffer(GL_ARRAY_BUFFER, m_quadBuffer);
+                glBufferData(GL_ARRAY_BUFFER, sizeof(quad), quad, GL_STATIC_DRAW);
+                glGenVertexArrays(1, &m_vao);
+                glBindVertexArray(m_vao);
+                glEnableVertexAttribArray(0);
+                glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), nullptr);
+                glBindVertexArray(0);
+                RecordProperty("lane", m_lane.empty() ? "ambient" : m_lane.c_str());
+            }
+
+            void TearDown() override {
+                if (!Ready()) return;
+                glUseProgram(0);
+                glBindVertexArray(0);
+                glBindSampler(0, 0);
+                glBindBuffer(GL_ARRAY_BUFFER, 0);
+                if (m_vao != 0) glDeleteVertexArrays(1, &m_vao);
+                if (m_quadBuffer != 0) glDeleteBuffers(1, &m_quadBuffer);
+                if (m_program != 0) glDeleteProgram(m_program);
+            }
+
+            // GTEST_SKIP() returns from the function it is written in, so this cannot report
+            // through a return value; every caller pairs it with `if (IsSkipped()) return;`.
+            void SkipUnlessTheLaneIsAssertableHere(bool needsTheEmitters) {
+                if (m_lane.empty()) {
+                    GTEST_SKIP() << "runs only in its own lane: the three ObjectSubsystemControl. "
+                                    "ctest entries set " << kLaneMarker
+                                 << " together with the MOBILEGL_PIPE_PUSH bitmask that arm means, "
+                                    "MOBILEGL_PIPE_STATS=1, MOBILEGL_PIPE_STATS_PERIOD=1 and a "
+                                    "private MOBILEGL_LOG_FILE_PATH. None of that is configured in "
+                                    "the ambient entries, and the ambient log is shared, so a read "
+                                    "here would race.";
+                    return;
+                }
+                if (!BuildMarkerIsSet("MGITEST_PIPE_PUSH_BUILD")) {
+                    GTEST_SKIP() << "this library was built without MOBILEGL_PIPE_PUSH: there are no "
+                                    "subsystem bits to clear, P4a's five CallClass members do not "
+                                    "exist and the summary line carries no emit[...] bracket. The "
+                                    "entry is registered here anyway so that `ctest -L "
+                                    "integration-gpu` names the same tests in the pull build and the "
+                                    "push build (gate G2).";
+                    return;
+                }
+                if (needsTheEmitters && !BuildMarkerIsSet("MGITEST_PIPE_OBJECT_EMITTER_PRESENT")) {
+                    GTEST_SKIP() << "subsystem not implemented on this tree: no source under "
+                                    "MobileGL/MG_Impl/Pipe/ emits FramebufferEmissions, so nothing "
+                                    "sends a P4a record, every counter in the emit[] bracket is "
+                                    "structurally zero in BOTH lanes and the difference between them "
+                                    "is not observable yet. P4a packages B (framebuffer, texture) "
+                                    "and C (sampler, image, program) own those emitters; this "
+                                    "control arms itself when they land, whatever files they use.";
+                    return;
+                }
+                if (PipeStatsWindow::LibraryLogPath().empty()) {
+                    GTEST_SKIP() << "the lane configured no MOBILEGL_LOG_FILE_PATH, and the library's "
+                                    "own log is the only channel this module has for reading "
+                                    "PipeStats and the bring-up's refusal line";
+                    return;
+                }
+            }
+
+            // The workload, and every one of P4a's four families is in it exactly once per draw:
+            // a USER FRAMEBUFFER with a texture attachment (bit 9), a TEXTURE with parameters and
+            // an upload (bit 10), an explicit SAMPLER OBJECT on the unit (bit 11) and a PROGRAM
+            // with a default-uniform-block write (bit 12). A lane that steered only one of the four
+            // would move only its own counter, which is why they are counted separately.
+            void RunTheWorkload() {
+                std::vector<std::uint8_t> texels(kTextureSize * kTextureSize * 4);
+                for (std::size_t i = 0; i < texels.size(); i += 4) {
+                    texels[i] = 0;
+                    texels[i + 1] = 255;
+                    texels[i + 2] = 0;
+                    texels[i + 3] = 255;
+                }
+                glGenTextures(1, &m_texture);
+                glBindTexture(GL_TEXTURE_2D, m_texture);
+                glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, kTextureSize, kTextureSize, 0, GL_RGBA,
+                             GL_UNSIGNED_BYTE, texels.data());
+                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_BASE_LEVEL, 0);
+                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 0);
+
+                glGenSamplers(1, &m_sampler);
+                glSamplerParameteri(m_sampler, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+                glSamplerParameteri(m_sampler, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+                glSamplerParameteri(m_sampler, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
+                glSamplerParameteri(m_sampler, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
+
+                // The user framebuffer, drawn into once per iteration so that the framebuffer
+                // record has a reason to move: the binding alternates between it and the default
+                // framebuffer, which is exactly what a per-target set_framebuffer_state counts.
+                glGenTextures(1, &m_attachment);
+                glBindTexture(GL_TEXTURE_2D, m_attachment);
+                glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, kTextureSize, kTextureSize, 0, GL_RGBA,
+                             GL_UNSIGNED_BYTE, nullptr);
+                glBindTexture(GL_TEXTURE_2D, 0);
+                glGenFramebuffers(1, &m_fbo);
+                glBindFramebuffer(GL_FRAMEBUFFER, m_fbo);
+                glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D,
+                                       m_attachment, 0);
+                BindDefaultFramebuffer();
+
+                for (int draw = 0; draw < kDrawsInTheWindow; ++draw) {
+                    // Into the user framebuffer...
+                    glBindFramebuffer(GL_FRAMEBUFFER, m_fbo);
+                    glViewport(0, 0, kTextureSize, kTextureSize);
+                    glUseProgram(m_program);
+                    glUniform1i(glGetUniformLocation(m_program, "uTex"), 0);
+                    glActiveTexture(GL_TEXTURE0);
+                    glBindTexture(GL_TEXTURE_2D, m_texture);
+                    glBindSampler(0, m_sampler);
+                    glBindVertexArray(m_vao);
+                    glDrawArrays(GL_TRIANGLES, 0, 6);
+                    // ...and into the default one, which is what the case reads back.
+                    BindDefaultFramebuffer();
+                    glViewport(0, 0, Gl().Width(), Gl().Height());
+                    glDrawArrays(GL_TRIANGLES, 0, 6);
+                    // One sub-region upload per iteration, so the client-side texture upload
+                    // counter (ctu) has something to count and the server's tex[emit=] has the
+                    // same something.
+                    const std::uint8_t green[4] = {0, 255, 0, 255};
+                    glBindTexture(GL_TEXTURE_2D, m_texture);
+                    glTexSubImage2D(GL_TEXTURE_2D, 0, draw % kTextureSize, 0, 1, 1, GL_RGBA,
+                                    GL_UNSIGNED_BYTE, green);
+                }
+            }
+
+            void ReleaseTheWorkload() {
+                glBindSampler(0, 0);
+                glBindTexture(GL_TEXTURE_2D, 0);
+                BindDefaultFramebuffer();
+                if (m_fbo != 0) glDeleteFramebuffers(1, &m_fbo);
+                if (m_sampler != 0) glDeleteSamplers(1, &m_sampler);
+                if (m_texture != 0) glDeleteTextures(1, &m_texture);
+                if (m_attachment != 0) glDeleteTextures(1, &m_attachment);
+                m_fbo = m_sampler = m_texture = m_attachment = 0;
+            }
+
+            std::string m_lane;
+            GLuint m_program = 0;
+            GLuint m_vao = 0;
+            GLuint m_quadBuffer = 0;
+            GLuint m_texture = 0;
+            GLuint m_attachment = 0;
+            GLuint m_sampler = 0;
+            GLuint m_fbo = 0;
+        };
+
+        // ONE case per lane, and it is a constraint rather than a preference: this case READS the
+        // library log, the log is a per-LANE resource (the library opens it fopen(path, "w"), so
+        // every process in a lane truncates it), and a second case in the same lane would race this
+        // one under `ctest -j` with a failure indistinguishable from "the counter was never
+        // emitted". The CMake registration gives each lane a TEST_FILTER naming one case.
+        TEST_F(ObjectSubsystemControlScenario, ClearingTheP4aBitsStopsTheEmissionsAndNotThePixels) {
+            if (!Ready()) return;
+            SkipUnlessTheLaneIsAssertableHere(/*needsTheEmitters=*/true);
+            if (IsSkipped()) return;
+            if (LaneIsAConsumerLane(m_lane)) {
+                GTEST_SKIP() << "the two consumer lanes run their own case instead "
+                                "(TheAppliersNoConsumerBeltNeverFiresBehindTheClientsGate). They "
+                                "are at the phase default on both backends and their subject is "
+                                "c0f's gate/belt pair, not the on/off A/B: on the backend with no "
+                                "consumer the emit[] bracket is structurally zero AT the default "
+                                "mask, which is neither the on-lane's expectation nor the "
+                                "off-lane's.";
+            }
+            if (LaneIsARefusalLane(m_lane)) {
+                GTEST_SKIP() << "the refusal lanes run their own case instead (0x9ff -> "
+                                "ASamplerBitWithoutTheTextureBitIsRefusedAndNamed, 0x5ff -> "
+                                "ATextureBitWithoutTheSamplerBitIsRefusedAndNamed): a refused "
+                                "subsystem's emission counts are neither the on-lane's nor the "
+                                "off-lane's, and asserting either would be reading a third arm as "
+                                "if it were one of the two.";
+            }
+
+            BindDefaultFramebuffer();
+            Gl().EndFrame(); // close the setup window: everything below is one window
+
+            ClearTo(0.0f, 0.0f, 0.0f, 1.0f);
+            RunTheWorkload();
+            ASSERT_EQ(FirstGLError(), GLenum(GL_NO_ERROR)) << "the workload left a GL error behind";
+            const Image image = ReadPixels(Gl().Width(), Gl().Height());
+            Gl().EndFrame(); // the swap that emits the window covering exactly the work above
+
+            const PipeStatsWindow::Window window = PipeStatsWindow::LastFromLaneLog();
+            ASSERT_TRUE(window.found)
+                << "no 'MGPipe stats:' line in " << PipeStatsWindow::LibraryLogPath()
+                << ". This IS a push build (the lane checked MGITEST_PIPE_PUSH_BUILD before getting "
+                   "here), so either MOBILEGL_PIPE_STATS / MOBILEGL_PIPE_STATS_PERIOD did not reach "
+                   "the process, or no summary line was emitted at all because nothing reached "
+                   "PipeStats::OnPresent.";
+            RecordProperty("stats_line", window.line.c_str());
+
+            // The five counters of the emit[] bracket, read individually so that a lane which
+            // steered one family and not another says WHICH.
+            const long long framebuffer = PipeStatsWindow::CounterOrAbsent(window, "fbe");
+            const long long samplerViews = PipeStatsWindow::CounterOrAbsent(window, "sve");
+            const long long samplerStates = PipeStatsWindow::CounterOrAbsent(window, "sse");
+            const long long shaderImages = PipeStatsWindow::CounterOrAbsent(window, "sie");
+            const long long clientUploads = PipeStatsWindow::CounterOrAbsent(window, "ctu");
+            ASSERT_GE(framebuffer, 0)
+                << "the summary line carries no fbe= field, so this build's PipeStats has no P4a "
+                   "emission counters to read: "
+                << window.line;
+            ASSERT_GE(samplerViews, 0) << "no sve= field: " << window.line;
+            ASSERT_GE(samplerStates, 0) << "no sse= field: " << window.line;
+            ASSERT_GE(shaderImages, 0) << "no sie= field: " << window.line;
+            ASSERT_GE(clientUploads, 0) << "no ctu= field: " << window.line;
+            const long long total = framebuffer + samplerViews + samplerStates + shaderImages +
+                                    clientUploads;
+
+            if (m_lane == kLaneOn) {
+                EXPECT_GT(total, 0)
+                    << "with bits 9|10|11|12 SET the four P4a families are the path this workload "
+                       "takes - a user framebuffer bound and unbound "
+                    << kDrawsInTheWindow
+                    << " times, a texture with parameters and a sub-region upload per iteration, an "
+                       "explicit sampler object on the unit and a program with a default-uniform "
+                       "write - so the window's emit[] bracket must carry something. All five "
+                       "reading zero means the emitters never ran on the arm that is supposed to run "
+                       "them. It reported: "
+                    << window.line;
+                // The framebuffer family on its own, because it is the one that would be hidden by
+                // a large upload count: a suppressor that stopped suppressing shows up as fbe
+                // tracking the DRAW count, and a family that never emitted shows up as zero.
+                EXPECT_GT(framebuffer, 0)
+                    << "fbe= is zero on the ON lane: set_framebuffer_state never went out even "
+                       "though the workload bound a user framebuffer and the default framebuffer "
+                    << kDrawsInTheWindow << " times each. " << window.line;
+            } else if (m_lane == kLaneOff) {
+                EXPECT_EQ(total, 0)
+                    << "with bits 9|10|11|12 CLEARED (MOBILEGL_PIPE_PUSH=0x1ff, P3a's default) the "
+                       "frontend dispatch must fall through to the legacy MGB_CTX-reading arms and "
+                       "emit nothing through any of the four P4a families, so every counter in the "
+                       "emit[] bracket must be zero. A non-zero count here is the dead-switch "
+                       "reading: the bits are being ignored, both arms run the same code, and every "
+                       "push-vs-pull number taken against this A/B is measuring one arm twice. It "
+                       "reported: "
+                    << window.line;
+            } else {
+                FAIL() << "unknown " << kLaneMarker << " value '" << m_lane
+                       << "': the arms are on / off / refused / refused-texture / consumer / "
+                          "no-consumer. Reading an unrecognised name as any of them would make "
+                          "this lane assert another arm's expectation while claiming to test "
+                          "this one.";
+            }
+
+            // ... and the picture is the same whichever arm ran.
+            EXPECT_TRUE(RegionIsMostly(image, kInset, image.Width() - kInset, kInset,
+                                       image.Height() - kInset, "green", 0.0,
+                                       "the sampled draw [" + m_lane + "]"))
+                << "the subsystem bits changed what is DRAWN, which is not an A/B - the handle path "
+                   "and the legacy path must produce the same pixels from the same texture, sampler "
+                   "and framebuffer.";
+
+            ReleaseTheWorkload();
+        }
+
+        // ------------------------------------------------------------------------------------
+        // D-K2's dependency refusal, in the direction that has to be refused.
+        //
+        // 0x9ff is bits 0..8 (everything P3a shipped) plus bit 11 (samplers) and WITHOUT bit 10
+        // (texture resources). Every MGPBoundView::Texture and every MGPImageView::Res names a
+        // Texture handle, and only bit 10 populates the texture slot table, so with bit 11 alone
+        // every lookup would miss and the unit walk would `continue` without unbinding - a
+        // half-run subsystem, which ROADMAP.md:7 forbids as loudly as a dead switch. The bring-up
+        // logs ONE error naming both bits, refuses bit 11, and runs the legacy sampler arm.
+        //
+        // TWO ASSERTIONS, and the second is the one that stops this from being a log-scraping test:
+        // the refusal is NAMED in the library's own log, and the run then draws the same picture as
+        // every other lane. A refusal that aborted the process, and a refusal that silently let the
+        // half-configured arm run, are both failures - and they look completely different here.
+        // ------------------------------------------------------------------------------------
+        TEST_F(ObjectSubsystemControlScenario, ASamplerBitWithoutTheTextureBitIsRefusedAndNamed) {
+            if (!Ready()) return;
+            // needsTheEmitters=false: the refusal is a BRING-UP decision made from the bitmask
+            // alone, so it is assertable before any emitter exists - which is exactly what makes it
+            // the one P4a control that is not vacuous on the contract tree.
+            SkipUnlessTheLaneIsAssertableHere(/*needsTheEmitters=*/false);
+            if (IsSkipped()) return;
+            if (m_lane != kLaneRefused) {
+                GTEST_SKIP() << "runs only in the refusal lane (MOBILEGL_PIPE_PUSH=0x9ff): the "
+                                "on/off lanes configure a mask whose dependencies are all satisfied, "
+                                "so there is no refusal there to find and a search for one would "
+                                "report a healthy lane as red.";
+            }
+            // The refusal is decided from the bitmask, but it is a BACKEND's decision: D-K2 puts it
+            // in ResolveSamplersSubsystemArm(), beside the bit-8-requires-bit-7 refusal that
+            // already ships, and that function is package D's (Managers.cpp). A backend that does
+            // not yet honour P4a's mask at all cannot refuse a dependency inside it, so on such a
+            // tree there is nothing here to find and this case SKIPS rather than reporting the
+            // absence of an unimplemented subsystem as a failure. The marker is the same one
+            // HandleRecycle's P4a cases read - "does any source under this backend name one of the
+            // four P4a subsystem constants" - because naming the constant is exactly what honouring
+            // the mask means.
+            {
+                const std::string& backend = Gl().BackendName();
+                const std::string marker =
+                    "MGITEST_HANDLE_REKEY_OBJECTS_" + (backend == "DirectVulkan"
+                                                           ? std::string("DirectVulkan")
+                                                           : std::string("DirectGLES"));
+                if (!BuildMarkerIsSet(marker.c_str())) {
+                    GTEST_SKIP() << "subsystem not implemented on this tree: no source under "
+                                    "MobileGL/MG_Backend/"
+                                 << backend
+                                 << " names any of kMGPipeSubsystem{Framebuffer, TextureResources, "
+                                    "Samplers, Programs}, so this backend does not honour P4a's mask "
+                                    "and cannot refuse a dependency inside it. D-K2's refusal lives "
+                                    "in ResolveSamplersSubsystemArm() beside the bit-8-requires-bit-7 "
+                                    "one that already ships (Managers.cpp:2393-2410), which is P4a "
+                                    "package D's file; this control arms itself when that lands. The "
+                                    "lane itself is not wasted: the library came up under 0x9ff, "
+                                    "which on a tree with no P4a arm is P3a's mask plus one inert "
+                                    "bit, and a mask that aborted a bring-up would have failed this "
+                                    "entry before the skip.";
+                }
+            }
+
+            BindDefaultFramebuffer();
+            ClearTo(0.0f, 0.0f, 0.0f, 1.0f);
+            RunTheWorkload();
+            ASSERT_EQ(FirstGLError(), GLenum(GL_NO_ERROR))
+                << "the workload left a GL error behind on the refused lane, which would mean the "
+                   "refusal did not fall back cleanly to the legacy arm";
+            const Image image = ReadPixels(Gl().Width(), Gl().Height());
+            Gl().EndFrame();
+
+            const std::string log = PipeStatsWindow::ReadWholeFile(PipeStatsWindow::LibraryLogPath());
+            ASSERT_FALSE(log.empty())
+                << "the library wrote nothing to " << PipeStatsWindow::LibraryLogPath()
+                << ", so the refusal cannot be read back. MOBILEGL_LOG_FILE_PATH is the only channel "
+                   "this module has for the library's own report.";
+            // ONE LINE, at ERROR severity, saying it refused and naming BOTH bits. See
+            // FindTheRefusalLine: a substring search over the whole file cannot go red for the
+            // reason this case claims (F-M6).
+            const std::string refusal =
+                FindTheRefusalLine(log, SamplerBitSpellings(), TextureResourceBitSpellings());
+            EXPECT_FALSE(refusal.empty())
+                << "MOBILEGL_PIPE_PUSH=0x9ff sets the sampler subsystem (bit 11) without the texture "
+                   "resource subsystem (bit 10) it depends on, and no single ERROR line of the "
+                   "library's log both says it REFUSED and names the two bits. D-K2 requires ONE "
+                   "MGLOG_E naming both and a fall back to the legacy sampler arm; a mask that is "
+                   "silently half-honoured is the failure this case exists to catch, and it is "
+                   "invisible in the pixels by construction. Accepted spellings per bit are the "
+                   "constant's name, '(bit 11)' / '(bit 10)', and '0x800' / '0x400'. The log was "
+                << log.size() << " bytes and is at " << PipeStatsWindow::LibraryLogPath() << ".";
+            if (!refusal.empty()) {
+                // Printed on the pass as well: a reader of a green refusal lane must be able to
+                // see the sentence the lane went green on.
+                std::cout << "[ ObjectSubsystemControl ] refusal line: " << refusal << std::endl;
+                RecordProperty("refusal_line", refusal.c_str());
+            }
+
+            EXPECT_TRUE(RegionIsMostly(image, kInset, image.Width() - kInset, kInset,
+                                       image.Height() - kInset, "green", 0.0,
+                                       "the sampled draw [refused]"))
+                << "the refused configuration did not draw what every other lane draws. A refusal is "
+                   "supposed to run the LEGACY arm, which is the arm that ships in a pull build - so "
+                   "the pixels are the one thing it may not change.";
+
+            ReleaseTheWorkload();
+        }
+
+        // ------------------------------------------------------------------------------------
+        // D-K2's FOURTH dependency row, in the OTHER direction: bit 10 without bit 11 (ID-15).
+        //
+        // 0x5ff is bits 0..8 plus bit 10 (texture resources) and WITHOUT bit 11 (samplers).
+        //
+        // WHY THIS IS A REFUSAL AND NOT THE "FINE" MIRROR PAIR THE BRIEF ORIGINALLY CALLED IT.
+        // BRIEF-P4A.md's D-K2 says "bit 10 without bit 11 is fine", and that sentence is wrong for
+        // P4a AS BUILT: MGPTextureParams carries a BuiltinSampler, which is a SamplerCso HANDLE,
+        // and only bit 11 mints sampler CSOs - c0b's four unconditional mints deliberately exclude
+        // that kind (contract-v2.md), and package C content-addresses them through its own cache
+        // (ID-14). With bit 10 set and bit 11 clear every set_texture_params would therefore carry
+        // a NULL BuiltinSampler, which the applier treats as Fatal{ProtocolCorruption} (wire H1),
+        // and minting it client-side in the arm that exists to exclude samplers was rejected. So
+        // the dependency is real and it has to be refused at bring-up, exactly like bit 11 without
+        // bit 10 above and bit 8 without bit 7 one phase earlier. ID-15 puts the refusal in the
+        // texture family's Resolve*SubsystemArm - package D's Managers.cpp - and this case is the
+        // pin that says it is there.
+        //
+        // ON A TREE WHOSE BACKEND DOES NOT HONOUR P4a's MASK THIS SKIPS, NAMED, exactly as the
+        // 0x9ff case does and for the same reason: a backend that never reads the four constants
+        // cannot refuse a dependency between two of them, and reporting the absence of an
+        // unimplemented subsystem as a failure is what ID-2 forbids. Once the backend DOES name
+        // them the case is a hard pin, which is the point - if D's texture-family resolver honours
+        // the mask and does not carry this row, this entry is where that shows.
+        //
+        // WHAT THIS ARM DOES ON THE INTEGRATED TREE, corrected (review F-v2-m2). An earlier
+        // round's report told the integrator to expect this lane to go RED between esprytobj's
+        // integration and package D's rework, and to read that red as expected. That window does
+        // not exist: esprytobj v2 already carries D-K2's fourth row - Managers.cpp's
+        // ResolveTextureResourceSubsystemArm refuses bit 10 without bit 11 with the sentence this
+        // case matches - so the arm ARMS AND PASSES. A red here is therefore a real finding about
+        // that resolver (it stopped refusing, refused for the wrong reason, or printed the mirror
+        // sentence, which the direction check above is what catches) and must not be waved
+        // through as a sequencing artefact.
+        // ------------------------------------------------------------------------------------
+        TEST_F(ObjectSubsystemControlScenario, ATextureBitWithoutTheSamplerBitIsRefusedAndNamed) {
+            if (!Ready()) return;
+            // needsTheEmitters=false, for the 0x9ff case's reason: a bring-up decision made from
+            // the bitmask alone is assertable before any emitter exists.
+            SkipUnlessTheLaneIsAssertableHere(/*needsTheEmitters=*/false);
+            if (IsSkipped()) return;
+            if (m_lane != kLaneRefusedTexture) {
+                GTEST_SKIP() << "runs only in the texture-side refusal lane "
+                                "(MOBILEGL_PIPE_PUSH=0x5ff): every other lane configures a mask "
+                                "whose dependencies are satisfied or a different refusal, so there "
+                                "is nothing here to find and a search for one would report a "
+                                "healthy lane as red.";
+            }
+            {
+                const std::string& backend = Gl().BackendName();
+                const std::string marker =
+                    "MGITEST_HANDLE_REKEY_OBJECTS_" + (backend == "DirectVulkan"
+                                                           ? std::string("DirectVulkan")
+                                                           : std::string("DirectGLES"));
+                if (!BuildMarkerIsSet(marker.c_str())) {
+                    GTEST_SKIP() << "subsystem not implemented on this tree: no source under "
+                                    "MobileGL/MG_Backend/"
+                                 << backend
+                                 << " names any of kMGPipeSubsystem{Framebuffer, TextureResources, "
+                                    "Samplers, Programs}, so this backend does not honour P4a's mask "
+                                    "and cannot refuse a dependency inside it. D-K2's fourth row "
+                                    "(bit 10 requires bit 11, ID-15) lives in the texture family's "
+                                    "Resolve*SubsystemArm beside the bit-11-requires-bit-10 and "
+                                    "bit-8-requires-bit-7 refusals, which is P4a package D's file; "
+                                    "this control arms itself when that lands. The lane itself is "
+                                    "not wasted: the library came up under 0x5ff, which on a tree "
+                                    "with no P4a arm is P3a's mask plus one inert bit, and a mask "
+                                    "that aborted a bring-up would have failed this entry before "
+                                    "the skip.";
+                }
+            }
+
+            BindDefaultFramebuffer();
+            ClearTo(0.0f, 0.0f, 0.0f, 1.0f);
+            RunTheWorkload();
+            ASSERT_EQ(FirstGLError(), GLenum(GL_NO_ERROR))
+                << "the workload left a GL error behind on the refused lane, which would mean the "
+                   "refusal did not fall back cleanly to the legacy arm";
+            const Image image = ReadPixels(Gl().Width(), Gl().Height());
+            Gl().EndFrame();
+
+            const std::string log = PipeStatsWindow::ReadWholeFile(PipeStatsWindow::LibraryLogPath());
+            ASSERT_FALSE(log.empty())
+                << "the library wrote nothing to " << PipeStatsWindow::LibraryLogPath()
+                << ", so the refusal cannot be read back. MOBILEGL_LOG_FILE_PATH is the only channel "
+                   "this module has for the library's own report.";
+            // The same line shape as the 0x9ff arm, with the two bits' roles swapped: the bit that
+            // was SET is the texture-resource one and the bit it NEEDED is the sampler one. The
+            // swap is now a REAL difference between the two cases: FindTheRefusalLine requires the
+            // set bit to be named before " is set but " and the needed bit after it (F-v2-m1), so
+            // this call and the 0x9ff one above accept disjoint sentences. Espryt's is
+            // "kMGPipeSubsystemTextureResources (bit 10) is set but kMGPipeSubsystemSamplers
+            // (bit 11) is clear; MGPTextureParams::BuiltinSampler is a SamplerCso handle, only
+            // bit 11 mints sampler CSOs, and the applier's verdict for a null one is
+            // Fatal{ProtocolCorruption} - REFUSING the dependent bit and running the legacy arm.
+            // Set both bits, or clear both" (Managers.cpp, ResolveTextureResourceSubsystemArm).
+            const std::string refusal =
+                FindTheRefusalLine(log, TextureResourceBitSpellings(), SamplerBitSpellings());
+            EXPECT_FALSE(refusal.empty())
+                << "MOBILEGL_PIPE_PUSH=0x5ff sets the texture resource subsystem (bit 10) without "
+                   "the sampler subsystem (bit 11) that MGPTextureParams::BuiltinSampler depends on, "
+                   "and no single ERROR line of the library's log both says it REFUSED and names the "
+                   "two bits. Only bit 11 mints sampler CSOs, so every set_texture_params emitted "
+                   "under this mask would carry a null BuiltinSampler and the applier's Fatal is the "
+                   "next thing that happens - which is why this pair is a refusal at bring-up and "
+                   "not the harmless mirror of the 0x9ff one. Accepted spellings per bit are the "
+                   "constant's name, '(bit 10)' / '(bit 11)', and '0x400' / '0x800'. The log was "
+                << log.size() << " bytes and is at " << PipeStatsWindow::LibraryLogPath() << ".";
+            if (!refusal.empty()) {
+                std::cout << "[ ObjectSubsystemControl ] refusal line: " << refusal << std::endl;
+                RecordProperty("refusal_line", refusal.c_str());
+            }
+
+            EXPECT_TRUE(RegionIsMostly(image, kInset, image.Width() - kInset, kInset,
+                                       image.Height() - kInset, "green", 0.0,
+                                       "the sampled draw [refused-texture]"))
+                << "the refused configuration did not draw what every other lane draws. A refusal is "
+                   "supposed to run the LEGACY arm, which is the arm that ships in a pull build - so "
+                   "the pixels are the one thing it may not change.";
+
+            ReleaseTheWorkload();
+        }
+
+        // ------------------------------------------------------------------------------------
+        // c0f's GATE AND BELT, MEASURED TOGETHER (ID-39, ID-40).
+        //
+        // WHAT WENT WRONG AND WHY IT NEEDS A LANE. P4a's four families were wired without the
+        // gate P3a's buffers have had since PipeFill.cpp ~656: emission required the family's bit
+        // and nothing else. On Magma, which registers no MGPipeResourceOps, the client therefore
+        // emitted, THE APPLIER ACCEPTED, the client cleared its dirty flags on that acceptance -
+        // and Magma's legacy path then found nothing to upload. Sixty-six DirectVulkan cases went
+        // red at once, all texture-upload-shaped, and every one of them was green at 0x1ff. The
+        // fix has two halves that are deliberately independent: the client's gate (bit N AND
+        // wired AND a backend registered the ops) and the applier's belt (every P4a entry point
+        // returns accepted = false and counts RefusedNoConsumer when none did).
+        //
+        // THE ASSERTION IS THAT THE BELT NEVER FIRES, and it is the same assertion on both
+        // backends, which is what makes it worth having twice:
+        //
+        //   no-consumer (DirectVulkan, 0x1fff): the belt is the SAFETY NET. A non-zero count here
+        //     means a record reached the applier on a backend with no consumer - i.e. the client
+        //     gate leaked and only the belt stopped the dirty flag from being cleared. That is
+        //     ID-39's bug caught one layer later, and it is invisible in these pixels because the
+        //     belt does its job; the 66 red cases were in another suite entirely.
+        //   consumer (DirectGLES, 0x1fff): the CONTROL. Espryt registers the ops, so no entry
+        //     point may take the no-consumer arm at all. Without this lane a green above could
+        //     also mean "nothing is ever emitted anywhere", which is exactly what a gate that was
+        //     accidentally always-false would look like.
+        //
+        // A DELTA, not an absolute: the counter is process-global and other cases in this binary
+        // run before this one. MGPipeApplierReset also zeroes it, so a count that went DOWN is
+        // read as "the applier was reset and everything since is `after`" rather than as an
+        // underflow.
+        // ------------------------------------------------------------------------------------
+        TEST_F(ObjectSubsystemControlScenario, TheAppliersNoConsumerBeltNeverFiresBehindTheClientsGate) {
+            if (!Ready()) return;
+            // needsTheEmitters=false: the assertion is that a counter did NOT move, which is
+            // meaningful before the emitters land as well as after - and on the no-consumer lane
+            // it is meaningful precisely BECAUSE nothing may be emitted there.
+            SkipUnlessTheLaneIsAssertableHere(/*needsTheEmitters=*/false);
+            if (IsSkipped()) return;
+            if (!LaneIsAConsumerLane(m_lane)) {
+                GTEST_SKIP() << "runs only in the two consumer lanes (MGITEST_OBJECT_SUBSYSTEM_LANE="
+                             << kLaneConsumer << " / " << kLaneNoConsumer
+                             << "), which pin MOBILEGL_PIPE_PUSH at the phase default on the two "
+                                "backends. Every other lane configures a mask or a backend whose "
+                                "emission shape is a different question.";
+            }
+
+            unsigned long long before = 0;
+            if (!PeekPipeApplierRefusedNoConsumer(&before)) {
+                GTEST_SKIP() << "MGPipeApplierState::RefusedNoConsumer is out of reach here: there "
+                                "is no applier in a PULL build (it is #if MOBILEGL_PIPE_PUSH), and "
+                                "on Android this module links the shipping libMobileGL.so built "
+                                "-fvisibility=hidden. 'Could not look' is not 'did not fire'.";
+            }
+
+            BindDefaultFramebuffer();
+            ClearTo(0.0f, 0.0f, 0.0f, 1.0f);
+            RunTheWorkload();
+            ASSERT_EQ(FirstGLError(), GLenum(GL_NO_ERROR))
+                << "the workload left a GL error behind on the " << m_lane << " lane";
+            const Image image = ReadPixels(Gl().Width(), Gl().Height());
+            Gl().EndFrame();
+
+            unsigned long long after = 0;
+            ASSERT_TRUE(PeekPipeApplierRefusedNoConsumer(&after))
+                << "the counter could be read before the workload and not after it";
+            // Down means MGPipeApplierReset ran inside the window, so everything still counted is
+            // what happened since - which is the number this case is about either way.
+            const unsigned long long fired = after >= before ? after - before : after;
+
+            std::cout << "[ ObjectSubsystemControl ] " << m_lane
+                      << " lane: applier RefusedNoConsumer " << before << " -> " << after
+                      << " over the workload (delta " << fired << ")" << std::endl;
+            RecordProperty("refused_no_consumer_delta", static_cast<int>(fired));
+
+            EXPECT_EQ(fired, 0u)
+                << "the applier's no-consumer BELT fired " << fired
+                << " time(s) during this workload on the " << m_lane
+                << " lane. The belt exists so that a P4a record arriving on a backend that "
+                   "registered no MGPipeResourceOps is refused rather than accepted - and an "
+                   "accepted record is what makes the client clear the dirty flags whose texels "
+                   "nobody then uploads (ID-39: sixty-six DirectVulkan cases, all texture-upload "
+                   "shaped). A non-zero count means the CLIENT'S GATE let an emission through and "
+                   "only the belt caught it: the two are supposed to agree, and PipeFill's "
+                   "P4aFamilyHasItsConsumer() is where they stopped.";
+
+            // The pixels, on both lanes, for the reason every arm of this file asserts them: a
+            // backend running its legacy path because no consumer is registered must draw exactly
+            // what a backend running the handle arm draws.
+            EXPECT_TRUE(RegionIsMostly(image, kInset, image.Width() - kInset, kInset,
+                                       image.Height() - kInset, "green", 0.0,
+                                       "the sampled draw [" + m_lane + "]"))
+                << "the " << m_lane
+                << " lane did not draw what every other lane draws, so whatever the counter says, "
+                   "this configuration is not running the workload correctly.";
+
+            ReleaseTheWorkload();
+        }
+
+    } // namespace
+} // namespace MGITest

MobileGL/MG_IntegrationTest/Scenarios/P4aFinalFixScenario.cpp

@@ -0,0 +1,658 @@
+// MobileGL - MobileGL/MG_IntegrationTest/Scenarios/P4aFinalFixScenario.cpp
+// Copyright (c) 2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+//
+// Scenario - THE THREE FINDINGS OF THE P4a FINAL WHOLE-DIFF REVIEW (final-review-v1.md C-1, C-2,
+// M-A), each pinned by the public-GL sequence that was red on the tree the review read and is
+// green with its fix. Every sequence here is legal GL and none of the 80-odd scenarios before
+// this file drove it, which is how two criticals shipped through a green gate.
+//
+//   C-1  The client never passed the applier the LEVEL a respecify redefines, so every per-level
+//        glTexImage*D / glGenerateMipmap grow took the applier's whole-resource arm and dropped
+//        EVERY pending upload of the texture - including a level the applier had already
+//        accepted and whose client-side dirty flag was therefore already clear (D-D5 step 1).
+//        Nobody owed those texels any more. The window is "accepted but not yet consumed":
+//        a verb the texture is not reached by (a draw with another texture) drains the level
+//        into the applier, Espryt does not sync the texture, and the next level definition eats
+//        the entry. Two hazard cases (a level-1 definition, a glGenerateMipmap) read a black
+//        level 0 on the handle arm; the three controls beside them (no verb between, level 0
+//        consumed first, an immediate generate) are red on every arm, which is what pins the
+//        window rather than the mip path.
+//   C-2  A dead-but-not-recycled texture handle still resolved to the freed ITextureObject*
+//        inside the client's drain: the death helper freed the slot without telling the emitter,
+//        the drain list kept the level, and the next verb's drain called virtual
+//        GetStorageType() on freed memory - `glTexImage2D; glDeleteTextures; <any verb>` was a
+//        SIGABRT ("pure virtual method called") at the shipping default mask. The same
+//        delete-then-use shape is driven for every kind P4a mints (renderbuffer, sampler object,
+//        program, framebuffer) and for a slot recycled straight after the death (ABA), on both
+//        backends: the death path is backend-neutral by ruling (ID-8) and the DirectVulkan lane
+//        must see it too.
+//   M-A  Nothing produced kMGPipeBindSampler / kMGPipeBindShaderImage, so ImageBindableHint was
+//        dead: the applier never saw a texture become image-bound, the metadata respecify
+//        (ID-18 M4) had no live trigger, and the remint pull the hint exists to prevent was
+//        neither prevented nor counted. The case here reads the applier's record around a
+//        glBindImageTexture: the hint arrives as a metadata update that keeps the pending upload
+//        standing beside it, and the picture after the transition is the texels that upload
+//        carried.
+//
+// A WHITE-BOX READING THAT CANNOT BE TAKEN IS DECLINED BY NAME AND THE CASE CONTINUES with its
+// public-GL half (P4aSeamAuditScenario.cpp's shape): a pull build or a backend with no P4a
+// consumer holds no record to read, and skipping the whole case there would delete the verdict
+// those lanes carry. The C-1 and M-A cases assert their pictures on DirectGLES only - Espryt is
+// the one consumer of the texture records this phase wires, so on any other backend the handle
+// arm is inert by design and the picture proves nothing about it.
+
+#include <cstdint>
+#include <cstdlib>
+#include <iostream>
+#include <string>
+#include <vector>
+
+#include "../Harness/HeadlessGL.h"
+#include "../Harness/P4aFinalFixPeek.h"
+#include "../Harness/ScenarioFixture.h"
+
+#ifdef GLAPI
+#undef GLAPI
+#endif
+#define GL_GLEXT_PROTOTYPES
+#include <GL/gl.h>
+#include <GL/glcorearb.h>
+#undef GL_GLEXT_PROTOTYPES
+
+namespace MGITest {
+    namespace {
+
+        constexpr int kInset = 2;
+
+        constexpr const char* kVS = R"(#version 330 core
+in vec2 aPos;
+out vec2 vUv;
+void main() {
+    vUv = aPos * 0.5 + 0.5;
+    gl_Position = vec4(aPos, 0.0, 1.0);
+}
+)";
+
+        constexpr const char* kFS = R"(#version 330 core
+in vec2 vUv;
+uniform sampler2D uTex;
+out vec4 oColor;
+void main() { oColor = texture(uTex, vUv); }
+)";
+
+        struct Vertex {
+            float x, y;
+        };
+
+        class P4aFinalFixScenario : public ScenarioTest {
+        protected:
+            void SetUp() override {
+                ScenarioTest::SetUp();
+                if (!Ready()) return;
+                std::string error;
+                m_program = CompileProgram(kVS, kFS, &error);
+                ASSERT_NE(m_program, 0u) << error;
+
+                static const Vertex quad[6] = {{-1.0f, -1.0f}, {1.0f, -1.0f}, {1.0f, 1.0f},
+                                               {-1.0f, -1.0f}, {1.0f, 1.0f},  {-1.0f, 1.0f}};
+                glGenBuffers(1, &m_quadBuffer);
+                glBindBuffer(GL_ARRAY_BUFFER, m_quadBuffer);
+                glBufferData(GL_ARRAY_BUFFER, sizeof(quad), quad, GL_STATIC_DRAW);
+                glGenVertexArrays(1, &m_vao);
+                glBindVertexArray(m_vao);
+                glEnableVertexAttribArray(0);
+                glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), nullptr);
+                glBindVertexArray(0);
+                glDisable(GL_BLEND);
+                glDisable(GL_SCISSOR_TEST);
+                glDisable(GL_DEPTH_TEST);
+                glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
+
+                // The "other" texture: a complete, single-level white texture, so a draw that
+                // samples it is a verb the texture under test is not reached by.
+                m_other = MakeLevel0(255, 255, 255, /*maxLevel=*/0);
+                while (glGetError() != GL_NO_ERROR) {
+                }
+            }
+
+            void TearDown() override {
+                if (!Ready()) return;
+                glUseProgram(0);
+                glBindVertexArray(0);
+                glBindTexture(GL_TEXTURE_2D, 0);
+                glBindBuffer(GL_ARRAY_BUFFER, 0);
+                glBindFramebuffer(GL_FRAMEBUFFER, 0);
+                if (m_other != 0) glDeleteTextures(1, &m_other);
+                if (m_vao != 0) glDeleteVertexArrays(1, &m_vao);
+                if (m_quadBuffer != 0) glDeleteBuffers(1, &m_quadBuffer);
+                if (m_program != 0) glDeleteProgram(m_program);
+                while (glGetError() != GL_NO_ERROR) {
+                }
+            }
+
+            // The C-1 and M-A pictures are about Espryt's consumption of the texture records;
+            // Magma registers no consumer for the P4a families (c0f), so the handle arm is inert
+            // there by design and a green picture proves nothing about the finding. Marks the
+            // case skipped; the caller tests IsSkipped() and returns.
+            void SkipUnlessEspryt(const char* what) {
+                if (Gl().BackendName() == "DirectGLES") return;
+                GTEST_SKIP() << what << " is consumed by DirectGLES only; backend is " << Gl().BackendName();
+            }
+
+            static std::vector<std::uint8_t> Solid(int size, std::uint8_t r, std::uint8_t g, std::uint8_t b) {
+                std::vector<std::uint8_t> texels(static_cast<std::size_t>(size) * size * 4);
+                for (std::size_t i = 0; i < texels.size(); i += 4) {
+                    texels[i] = r;
+                    texels[i + 1] = g;
+                    texels[i + 2] = b;
+                    texels[i + 3] = 255;
+                }
+                return texels;
+            }
+
+            // A 4x4 level 0 of one colour, NEAREST_MIPMAP_NEAREST with the level range clamped
+            // to `maxLevel`, so a single-level texture is complete and a chain is complete once
+            // its levels exist.
+            static GLuint MakeLevel0(std::uint8_t r, std::uint8_t g, std::uint8_t b, int maxLevel, int size = 4) {
+                const std::vector<std::uint8_t> texels = Solid(size, r, g, b);
+                GLuint texture = 0;
+                glGenTextures(1, &texture);
+                glBindTexture(GL_TEXTURE_2D, texture);
+                glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, size, size, 0, GL_RGBA, GL_UNSIGNED_BYTE, texels.data());
+                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST_MIPMAP_NEAREST);
+                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_BASE_LEVEL, 0);
+                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, maxLevel);
+                glBindTexture(GL_TEXTURE_2D, 0);
+                return texture;
+            }
+
+            static void DefineLevel1(GLuint texture, std::uint8_t r, std::uint8_t g, std::uint8_t b) {
+                const std::vector<std::uint8_t> texels = Solid(2, r, g, b);
+                glBindTexture(GL_TEXTURE_2D, texture);
+                glTexImage2D(GL_TEXTURE_2D, 1, GL_RGBA8, 2, 2, 0, GL_RGBA, GL_UNSIGNED_BYTE, texels.data());
+                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 1);
+                glBindTexture(GL_TEXTURE_2D, 0);
+            }
+
+            // A full-viewport draw sampling `texture` on unit 0 through `program` (the fixture's
+            // by default). The viewport is far larger than the 4x4 base level, so this is
+            // MAGNIFICATION and reads LEVEL 0 whatever the chain holds above it.
+            Image DrawSampled(GLuint texture, GLuint program = 0) {
+                if (program == 0) program = m_program;
+                BindDefaultFramebuffer();
+                glViewport(0, 0, Gl().Width(), Gl().Height());
+                glUseProgram(program);
+                glUniform1i(glGetUniformLocation(program, "uTex"), 0);
+                glActiveTexture(GL_TEXTURE0);
+                glBindTexture(GL_TEXTURE_2D, texture);
+                glBindVertexArray(m_vao);
+                glDrawArrays(GL_TRIANGLES, 0, 6);
+                Image image = ReadPixels(Gl().Width(), Gl().Height());
+                glBindTexture(GL_TEXTURE_2D, 0);
+                glBindVertexArray(0);
+                Gl().EndFrame();
+                return image;
+            }
+
+            ::testing::AssertionResult Mostly(const Image& image, const char* color, const std::string& when) {
+                return RegionIsMostly(image, kInset, image.Width() - kInset, kInset, image.Height() - kInset, color,
+                                      0.0, when);
+            }
+
+            void Report(const char* caseName, const Image& image) {
+                const char* mask = std::getenv("MOBILEGL_PIPE_PUSH");
+                const int cx = image.Width() / 2;
+                const int cy = image.Height() / 2;
+                std::cout << "[ P4aFinalFix ] case=" << caseName << " backend=" << Gl().BackendName()
+                          << " MOBILEGL_PIPE_PUSH=" << (mask ? mask : "(unset)") << " centre=" << image.At(cx, cy)
+                          << " (" << image.ColorName(cx, cy) << ")" << std::endl;
+            }
+
+            // The white-box gate of the M-A case: true when the applier holds a record for the
+            // texture in this process. Prints the decline.
+            bool RecordIsReadable(unsigned glTextureName, const char* what, PipeTextureResourceRecordPeek* out) {
+                if (PeekPipeTextureResourceRecord(glTextureName, out)) return true;
+                std::cout << "[ P4aFinalFix ] white-box reading DECLINED for " << what
+                          << ": the applier holds no record for texture " << glTextureName
+                          << " (a pull build, or a backend with no P4a consumer); the public-GL half of "
+                             "the case still runs"
+                          << std::endl;
+                RecordProperty("p4a_finalfix_white_box", "declined");
+                return false;
+            }
+
+            GLuint m_program = 0;
+            GLuint m_vao = 0;
+            GLuint m_quadBuffer = 0;
+            GLuint m_other = 0;
+        };
+
+        // ======================================================================================
+        // C-1: a per-level definition around a verb the texture is not reached by
+        // ======================================================================================
+
+        // THE HAZARD. L0's upload is accepted at the unrelated draw's validate point (the client
+        // clears its flag), Espryt never syncs T there (it is bound nowhere), then the level-1
+        // definition respecifies the resource. Before the fix that respecify carried no level and
+        // the applier dropped every pending upload; level 0 was allocated undefined.
+        TEST_F(P4aFinalFixScenario, PerLevelDefinitionAcrossAnUnrelatedDraw) {
+            if (!Ready()) return;
+            SkipUnlessEspryt("C-1's per-level respecify");
+            if (IsSkipped()) return;
+
+            const GLuint texture = MakeLevel0(255, 0, 0, /*maxLevel=*/0);
+            const Image unrelated = DrawSampled(m_other);
+            EXPECT_TRUE(Mostly(unrelated, "white", "the unrelated draw"));
+            DefineLevel1(texture, 255, 0, 0);
+            const Image image = DrawSampled(texture);
+            ASSERT_EQ(FirstGLError(), GLenum(GL_NO_ERROR));
+            Report("PerLevelDefinitionAcrossAnUnrelatedDraw", image);
+            EXPECT_TRUE(Mostly(image, "red",
+                               "level 0 after a level-1 definition that followed a draw the texture was not "
+                               "reached by - its accepted-but-unconsumed upload was dropped by the whole-"
+                               "resource arm"));
+            GLuint cleanup = texture;
+            glDeleteTextures(1, &cleanup);
+        }
+
+        // CONTROL: both levels defined before any verb; both are pending at the first sync.
+        TEST_F(P4aFinalFixScenario, ConsecutiveDefinitionsNoVerbBetween) {
+            if (!Ready()) return;
+            SkipUnlessEspryt("C-1's per-level respecify");
+            if (IsSkipped()) return;
+
+            const GLuint texture = MakeLevel0(255, 0, 0, /*maxLevel=*/0);
+            DefineLevel1(texture, 255, 0, 0);
+            const Image image = DrawSampled(texture);
+            ASSERT_EQ(FirstGLError(), GLenum(GL_NO_ERROR));
+            Report("ConsecutiveDefinitionsNoVerbBetween", image);
+            EXPECT_TRUE(Mostly(image, "red", "level 0 with both levels defined back to back"));
+            GLuint cleanup = texture;
+            glDeleteTextures(1, &cleanup);
+        }
+
+        // CONTROL: level 0 is consumed by Espryt (T is sampled) before level 1 is defined.
+        TEST_F(P4aFinalFixScenario, LevelZeroConsumedBeforeLevelOne) {
+            if (!Ready()) return;
+            SkipUnlessEspryt("C-1's per-level respecify");
+            if (IsSkipped()) return;
+
+            const GLuint texture = MakeLevel0(255, 0, 0, /*maxLevel=*/0);
+            const Image first = DrawSampled(texture);
+            EXPECT_TRUE(Mostly(first, "red", "level 0 alone"));
+            DefineLevel1(texture, 255, 0, 0);
+            const Image image = DrawSampled(texture);
+            ASSERT_EQ(FirstGLError(), GLenum(GL_NO_ERROR));
+            Report("LevelZeroConsumedBeforeLevelOne", image);
+            EXPECT_TRUE(Mostly(image, "red", "level 0 after level 1 was added to a synced texture"));
+            GLuint cleanup = texture;
+            glDeleteTextures(1, &cleanup);
+        }
+
+        // THE HAZARD, glGenerateMipmap flavour: the frontend grows the level chain (one
+        // AllocateStorage -> respecify per level) BEFORE the backend generate runs, with level 0
+        // accepted-but-unconsumed. The driver then built the chain from an undefined level 0.
+        TEST_F(P4aFinalFixScenario, GenerateMipmapAcrossAnUnrelatedDraw) {
+            if (!Ready()) return;
+            SkipUnlessEspryt("C-1's per-level respecify");
+            if (IsSkipped()) return;
+
+            const GLuint texture = MakeLevel0(255, 0, 0, /*maxLevel=*/1000);
+            const Image unrelated = DrawSampled(m_other);
+            EXPECT_TRUE(Mostly(unrelated, "white", "the unrelated draw"));
+            glBindTexture(GL_TEXTURE_2D, texture);
+            glGenerateMipmap(GL_TEXTURE_2D);
+            glBindTexture(GL_TEXTURE_2D, 0);
+            const Image image = DrawSampled(texture);
+            ASSERT_EQ(FirstGLError(), GLenum(GL_NO_ERROR));
+            Report("GenerateMipmapAcrossAnUnrelatedDraw", image);
+            EXPECT_TRUE(Mostly(image, "red",
+                               "level 0 after a glGenerateMipmap that followed a draw the texture was not "
+                               "reached by"));
+            GLuint cleanup = texture;
+            glDeleteTextures(1, &cleanup);
+        }
+
+        // CONTROL for the generate: no verb between the upload and the generate.
+        TEST_F(P4aFinalFixScenario, GenerateMipmapImmediately) {
+            if (!Ready()) return;
+            SkipUnlessEspryt("C-1's per-level respecify");
+            if (IsSkipped()) return;
+
+            const GLuint texture = MakeLevel0(255, 0, 0, /*maxLevel=*/1000);
+            glBindTexture(GL_TEXTURE_2D, texture);
+            glGenerateMipmap(GL_TEXTURE_2D);
+            glBindTexture(GL_TEXTURE_2D, 0);
+            const Image image = DrawSampled(texture);
+            ASSERT_EQ(FirstGLError(), GLenum(GL_NO_ERROR));
+            Report("GenerateMipmapImmediately", image);
+            EXPECT_TRUE(Mostly(image, "red", "level 0 after an immediate glGenerateMipmap"));
+            GLuint cleanup = texture;
+            glDeleteTextures(1, &cleanup);
+        }
+
+        // ======================================================================================
+        // C-2: delete-then-use, for every kind P4a mints, on both backends
+        // ======================================================================================
+
+        // A level goes dirty, the texture dies before any verb, and the next verb's drain walks
+        // the entry. Before the fix the emitter resolved the dead handle to the freed object and
+        // the drain called a virtual on it: SIGABRT in the first round. Eight rounds, and the
+        // lane registered with MALLOC_PERTURB_ scribbles every freed block so a resolved-but-
+        // dead pointer faults rather than reads the object's ghost.
+        TEST_F(P4aFinalFixScenario, ADirtyTextureDeletedBeforeAnyVerbIsWalkedByTheNextDrain) {
+            if (!Ready()) return;
+            for (int round = 0; round < 8; ++round) {
+                GLuint texture = 0;
+                glGenTextures(1, &texture);
+                glBindTexture(GL_TEXTURE_2D, texture);
+                const std::vector<std::uint8_t> texels = Solid(4, 255, 0, 0);
+                glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, 4, 4, 0, GL_RGBA, GL_UNSIGNED_BYTE, texels.data());
+                glBindTexture(GL_TEXTURE_2D, 0);
+                glDeleteTextures(1, &texture); // the last reference: the frontend object dies here
+                // Something else is allocated between the death and the drain, so the freed
+                // storage is not simply re-handed to the next object.
+                std::vector<std::uint8_t> churn(4096 + round * 1024, static_cast<std::uint8_t>(round));
+                (void)churn;
+                const Image image = DrawSampled(m_other); // the validate point: the drain runs here
+                ASSERT_EQ(FirstGLError(), GLenum(GL_NO_ERROR));
+                if (round == 0) Report("ADirtyTextureDeletedBeforeAnyVerbIsWalkedByTheNextDrain", image);
+                EXPECT_TRUE(Mostly(image, "white", "the draw after a dirty texture died"));
+            }
+        }
+
+        // ABA: the slot the dead texture held is handed straight to the next texture (the free
+        // list is LIFO). The new texture's picture must be its own, and the dead one's drain
+        // entry must not be replayed onto it.
+        TEST_F(P4aFinalFixScenario, ATextureRecycledOntoTheDeadSlotDoesNotInheritItsDrainEntry) {
+            if (!Ready()) return;
+            {
+                GLuint dead = 0;
+                glGenTextures(1, &dead);
+                glBindTexture(GL_TEXTURE_2D, dead);
+                const std::vector<std::uint8_t> texels = Solid(4, 255, 0, 0);
+                glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, 4, 4, 0, GL_RGBA, GL_UNSIGNED_BYTE, texels.data());
+                glBindTexture(GL_TEXTURE_2D, 0);
+                glDeleteTextures(1, &dead); // dirty, dead, no verb between
+            }
+            const GLuint successor = MakeLevel0(0, 0, 255, /*maxLevel=*/0, /*size=*/8);
+            const Image image = DrawSampled(successor);
+            ASSERT_EQ(FirstGLError(), GLenum(GL_NO_ERROR));
+            Report("ATextureRecycledOntoTheDeadSlotDoesNotInheritItsDrainEntry", image);
+            EXPECT_TRUE(Mostly(image, "blue", "the successor of a dead dirty texture on the recycled slot"));
+            const Image other = DrawSampled(m_other);
+            EXPECT_TRUE(Mostly(other, "white", "an unrelated draw after the recycled slot was used"));
+            GLuint cleanup = successor;
+            glDeleteTextures(1, &cleanup);
+        }
+
+        // A renderbuffer with defined storage, attached, cleared through its framebuffer, then
+        // both die before the next verb.
+        TEST_F(P4aFinalFixScenario, ARenderbufferAndItsFramebufferDeletedAfterAClearLeaveTheNextDrawIntact) {
+            if (!Ready()) return;
+            GLuint renderbuffer = 0;
+            glGenRenderbuffers(1, &renderbuffer);
+            glBindRenderbuffer(GL_RENDERBUFFER, renderbuffer);
+            glRenderbufferStorage(GL_RENDERBUFFER, GL_RGBA8, 8, 8);
+            GLuint fbo = 0;
+            glGenFramebuffers(1, &fbo);
+            glBindFramebuffer(GL_FRAMEBUFFER, fbo);
+            glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, renderbuffer);
+            ASSERT_EQ(glCheckFramebufferStatus(GL_FRAMEBUFFER), GLenum(GL_FRAMEBUFFER_COMPLETE));
+            glViewport(0, 0, 8, 8);
+            glClearColor(0.0f, 1.0f, 0.0f, 1.0f);
+            glClear(GL_COLOR_BUFFER_BIT);
+            const Image cleared = ReadPixels(8, 8);
+            EXPECT_TRUE(RegionIsMostly(cleared, 0, 8, 0, 8, "green", 0.0, "the renderbuffer after the clear"));
+            glBindFramebuffer(GL_FRAMEBUFFER, 0);
+            glBindRenderbuffer(GL_RENDERBUFFER, 0);
+            glDeleteFramebuffers(1, &fbo);
+            glDeleteRenderbuffers(1, &renderbuffer); // the attachment's last reference went with the FBO
+            const Image image = DrawSampled(m_other);
+            ASSERT_EQ(FirstGLError(), GLenum(GL_NO_ERROR));
+            Report("ARenderbufferAndItsFramebufferDeletedAfterAClearLeaveTheNextDrawIntact", image);
+            EXPECT_TRUE(Mostly(image, "white", "the draw after a renderbuffer and its framebuffer died"));
+        }
+
+        // A sampler object bound to the unit the draw samples through, deleted while bound: GL
+        // unbinds it from every unit at glDeleteSamplers, and the texture's own parameters apply
+        // again. Both draws must be the texture's colour.
+        TEST_F(P4aFinalFixScenario, ASamplerObjectDeletedWhileBoundLeavesTheNextDrawIntact) {
+            if (!Ready()) return;
+            const GLuint texture = MakeLevel0(255, 0, 0, /*maxLevel=*/0);
+            GLuint sampler = 0;
+            glGenSamplers(1, &sampler);
+            glSamplerParameteri(sampler, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+            glSamplerParameteri(sampler, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+            glBindSampler(0, sampler);
+            const Image withSampler = DrawSampled(texture);
+            EXPECT_TRUE(Mostly(withSampler, "red", "the draw through the bound sampler object"));
+            glDeleteSamplers(1, &sampler); // bound: unbound by the delete, then dies
+            const Image image = DrawSampled(texture);
+            ASSERT_EQ(FirstGLError(), GLenum(GL_NO_ERROR));
+            Report("ASamplerObjectDeletedWhileBoundLeavesTheNextDrawIntact", image);
+            EXPECT_TRUE(Mostly(image, "red", "the draw after the bound sampler object died"));
+            glBindSampler(0, 0);
+            GLuint cleanup = texture;
+            glDeleteTextures(1, &cleanup);
+        }
+
+        // A second program, in use when it is deleted (GL keeps it alive until it is no longer
+        // current), then released by a glUseProgram of the fixture's program: it dies there, and
+        // the draw that follows runs through the survivor.
+        TEST_F(P4aFinalFixScenario, AProgramDeletedWhileInUseLeavesTheNextDrawIntact) {
+            if (!Ready()) return;
+            std::string error;
+            const GLuint second = CompileProgram(kVS, kFS, &error);
+            ASSERT_NE(second, 0u) << error;
+            const GLuint texture = MakeLevel0(255, 0, 0, /*maxLevel=*/0);
+            const Image throughSecond = DrawSampled(texture, second);
+            EXPECT_TRUE(Mostly(throughSecond, "red", "the draw through the second program"));
+            glDeleteProgram(second); // current: flagged for deletion, still very much alive
+            const Image stillCurrent = DrawSampled(texture, second);
+            EXPECT_TRUE(Mostly(stillCurrent, "red", "the draw through a program flagged for deletion"));
+            const Image image = DrawSampled(texture); // glUseProgram(m_program): the second dies here
+            ASSERT_EQ(FirstGLError(), GLenum(GL_NO_ERROR));
+            Report("AProgramDeletedWhileInUseLeavesTheNextDrawIntact", image);
+            EXPECT_TRUE(Mostly(image, "red", "the draw after the deleted program was released"));
+            GLuint cleanup = texture;
+            glDeleteTextures(1, &cleanup);
+        }
+
+        // A framebuffer handed to the server BY NAME (a DSA clear emits a Named record, ID-19(c))
+        // and deleted before the next verb; its attachment lives on and carries the clear.
+        TEST_F(P4aFinalFixScenario, AFramebufferDeletedAfterADsaClearLeavesItsAttachmentIntact) {
+            if (!Ready()) return;
+            const GLuint texture = MakeLevel0(255, 0, 0, /*maxLevel=*/0);
+            GLuint fbo = 0;
+            glGenFramebuffers(1, &fbo);
+            glBindFramebuffer(GL_FRAMEBUFFER, fbo);
+            glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, texture, 0);
+            ASSERT_EQ(glCheckFramebufferStatus(GL_FRAMEBUFFER), GLenum(GL_FRAMEBUFFER_COMPLETE));
+            glBindFramebuffer(GL_FRAMEBUFFER, 0);
+            const GLfloat green[4] = {0.0f, 1.0f, 0.0f, 1.0f};
+            glClearNamedFramebufferfv(fbo, GL_COLOR, 0, green);
+            glDeleteFramebuffers(1, &fbo); // unbound and named: dies here
+            const Image image = DrawSampled(texture);
+            ASSERT_EQ(FirstGLError(), GLenum(GL_NO_ERROR));
+            Report("AFramebufferDeletedAfterADsaClearLeavesItsAttachmentIntact", image);
+            EXPECT_TRUE(Mostly(image, "green", "the attachment of a framebuffer that died after a DSA clear"));
+            GLuint cleanup = texture;
+            glDeleteTextures(1, &cleanup);
+        }
+
+        // ======================================================================================
+        // M-A: an image bind after the allocation is a metadata respecify with the hint set
+        // ======================================================================================
+
+        // glTexStorage2D (immutable: no later respecify to ride), a red upload consumed by a draw,
+        // then a blue upload drained by a verb the texture is not reached by (accepted, standing
+        // in the applier's pending set), then glBindImageTexture. The bind must reach the record
+        // as a metadata update - ImageBindableHint 1, the pending upload still standing - and the
+        // draw after it must show the blue that upload carried through the widened carrier the
+        // hint schedules.
+        TEST_F(P4aFinalFixScenario, AnImageBindAfterAllocationReachesTheApplierAsAMetadataRespecify) {
+            if (!Ready()) return;
+            SkipUnlessEspryt("M-A's image-bindable hint");
+            if (IsSkipped()) return;
+            GLint maxImageUnits = 0;
+            glGetIntegerv(GL_MAX_IMAGE_UNITS, &maxImageUnits);
+            while (glGetError() != GL_NO_ERROR) {
+            }
+            if (maxImageUnits < 1) {
+                GTEST_SKIP() << "no image units";
+                return;
+            }
+
+            // THE NUMBER ROADMAP OPEN QUESTION 2 ASKS FOR: a texture Espryt allocated BEFORE the
+            // hint reached it is re-minted image-bindable at the bind and its levels replayed
+            // from the client's shadow - one remint pull, counted. Arming the counter here is
+            // what makes it readable without a stats-enabled lane.
+            unsigned long long pullsBefore = 0;
+            const bool pullsReadable = PeekPipeStatsTextureRemintPulls(&pullsBefore);
+
+            GLuint texture = 0;
+            glGenTextures(1, &texture);
+            glBindTexture(GL_TEXTURE_2D, texture);
+            glTexStorage2D(GL_TEXTURE_2D, 1, GL_RGBA8, 4, 4);
+            const std::vector<std::uint8_t> red = Solid(4, 255, 0, 0);
+            glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 4, 4, GL_RGBA, GL_UNSIGNED_BYTE, red.data());
+            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+            glBindTexture(GL_TEXTURE_2D, 0);
+            const Image before = DrawSampled(texture); // allocated and consumed, NOT image-bindable
+            EXPECT_TRUE(Mostly(before, "red", "the immutable texture before the image bind"));
+
+            PipeTextureResourceRecordPeek record{};
+            const bool readable = RecordIsReadable(texture, "M-A's image-bindable hint", &record);
+            if (readable) {
+                EXPECT_EQ(record.ImageBindableHint, 0u) << "nothing has image-bound this texture yet";
+                EXPECT_EQ(record.PendingUploads, 0u) << "the red upload was consumed by the draw";
+            }
+
+            // A blue upload, drained by a verb that does not reach T: accepted, unconsumed.
+            const std::vector<std::uint8_t> blue = Solid(4, 0, 0, 255);
+            glBindTexture(GL_TEXTURE_2D, texture);
+            glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 4, 4, GL_RGBA, GL_UNSIGNED_BYTE, blue.data());
+            glBindTexture(GL_TEXTURE_2D, 0);
+            const Image unrelated = DrawSampled(m_other);
+            EXPECT_TRUE(Mostly(unrelated, "white", "the unrelated draw"));
+            if (readable) {
+                ASSERT_TRUE(PeekPipeTextureResourceRecord(texture, &record));
+                EXPECT_EQ(record.PendingUploads, 1u) << "the blue upload was not drained into the applier";
+            }
+            const unsigned long long serialBeforeBind = record.Serial;
+            unsigned long long uploadsBeforeBind = 0;
+            const bool uploadsReadable = PeekPipeStatsTextureUploadEmissions(&uploadsBeforeBind);
+
+            // THE TRANSITION. An immutable texture has no storage-defining respecify left, so the
+            // hint can only arrive as a metadata update (ID-18 M4). Espryt syncs the texture
+            // eagerly inside glBindImageTexture and the widening re-mints its storage, replaying
+            // every defined level from the shadow (the remint pull the counter below counts), so
+            // the standing upload is consumed by that regeneration here and the picture that
+            // follows is blue whatever the metadata respecify did to the record - the KEPT
+            // property is proved further down, on a texture no remint stands in front of.
+            (void)uploadsBeforeBind;
+            (void)uploadsReadable;
+            glBindImageTexture(0, texture, 0, GL_FALSE, 0, GL_READ_ONLY, GL_RGBA8);
+            ASSERT_EQ(FirstGLError(), GLenum(GL_NO_ERROR));
+            if (readable) {
+                ASSERT_TRUE(PeekPipeTextureResourceRecord(texture, &record));
+                EXPECT_EQ(record.ImageBindableHint, 1u)
+                    << "glBindImageTexture did not reach the applier's record as ImageBindableHint";
+                EXPECT_NE(record.BindMask & (1u << 6), 0u) << "kMGPipeBindShaderImage was not produced";
+                EXPECT_GT(record.Serial, serialBeforeBind) << "the metadata respecify moved no serial";
+            }
+
+            const Image image = DrawSampled(texture);
+            ASSERT_EQ(FirstGLError(), GLenum(GL_NO_ERROR));
+            Report("AnImageBindAfterAllocationReachesTheApplierAsAMetadataRespecify", image);
+            EXPECT_TRUE(Mostly(image, "blue", "the texture after the image bind that followed an unconsumed upload"));
+            glBindImageTexture(0, 0, 0, GL_FALSE, 0, GL_READ_ONLY, GL_RGBA8);
+            unsigned long long pullsAfter = 0;
+            if (pullsReadable && readable && PeekPipeStatsTextureRemintPulls(&pullsAfter)) {
+                EXPECT_EQ(pullsAfter, pullsBefore + 1)
+                    << "the re-mint of a texture allocated before its hint was not counted as a remint pull "
+                       "(trp= on the stats line is ROADMAP open question 2's number)";
+            }
+
+            // THE PREVENTION HALF, measured the other way round: a texture whose hint arrives at
+            // the bind, BEFORE its first sync, is allocated image-bindable up front and pulls
+            // nothing - the counter does not move.
+            GLuint early = 0;
+            glGenTextures(1, &early);
+            glBindTexture(GL_TEXTURE_2D, early);
+            glTexStorage2D(GL_TEXTURE_2D, 1, GL_RGBA8, 4, 4);
+            glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 4, 4, GL_RGBA, GL_UNSIGNED_BYTE, red.data());
+            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+            glBindTexture(GL_TEXTURE_2D, 0);
+            glBindImageTexture(0, early, 0, GL_FALSE, 0, GL_READ_ONLY, GL_RGBA8); // before any sync
+            const Image earlyImage = DrawSampled(early);
+            ASSERT_EQ(FirstGLError(), GLenum(GL_NO_ERROR));
+            EXPECT_TRUE(Mostly(earlyImage, "red", "a texture image-bound before its first sync"));
+            glBindImageTexture(0, 0, 0, GL_FALSE, 0, GL_READ_ONLY, GL_RGBA8);
+            unsigned long long pullsEarly = 0;
+            if (pullsReadable && readable && PeekPipeStatsTextureRemintPulls(&pullsEarly)) {
+                EXPECT_EQ(pullsEarly, pullsAfter)
+                    << "a texture whose hint preceded its first sync was still re-minted (the prevention "
+                       "half of the hint did not fire)";
+            }
+
+            // THE METADATA RESPECIFY KEEPS A STANDING UPLOAD, end to end and with no remint in the
+            // way: `early` is image-bindable already, so a NEW sticky bit reaching it - the
+            // RENDER_TARGET bit a DSA attachment produces at its setter (a Named record, ID-19(c)),
+            // with no sync of the texture in between - is a pure metadata update. The blue upload
+            // drained before it must still stand in the record afterwards (or, if a sync did run,
+            // have been uploaded rather than dropped) and reach the driver at the next draw.
+            glBindTexture(GL_TEXTURE_2D, early);
+            glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, 4, 4, GL_RGBA, GL_UNSIGNED_BYTE, blue.data());
+            glBindTexture(GL_TEXTURE_2D, 0);
+            const Image unrelatedAgain = DrawSampled(m_other);
+            EXPECT_TRUE(Mostly(unrelatedAgain, "white", "the unrelated draw"));
+            PipeTextureResourceRecordPeek earlyRecord{};
+            const bool earlyReadable = PeekPipeTextureResourceRecord(early, &earlyRecord);
+            if (earlyReadable) {
+                EXPECT_EQ(earlyRecord.PendingUploads, 1u) << "the blue upload was not drained into the applier";
+            }
+            const unsigned long long earlySerialBefore = earlyRecord.Serial;
+            unsigned long long uploadsBeforeAttach = 0;
+            const bool uploadsCounted = PeekPipeStatsTextureUploadEmissions(&uploadsBeforeAttach);
+            GLuint namedFbo = 0;
+            glCreateFramebuffers(1, &namedFbo);
+            glNamedFramebufferTexture(namedFbo, GL_COLOR_ATTACHMENT0, early, 0);
+            ASSERT_EQ(FirstGLError(), GLenum(GL_NO_ERROR));
+            if (earlyReadable) {
+                ASSERT_TRUE(PeekPipeTextureResourceRecord(early, &earlyRecord));
+                EXPECT_NE(earlyRecord.BindMask & (1u << 7), 0u)
+                    << "the DSA attachment did not produce kMGPipeBindRenderTarget";
+                EXPECT_GT(earlyRecord.Serial, earlySerialBefore) << "the mask move reached the record as no respecify";
+                unsigned long long uploadsAfterAttach = 0;
+                if (earlyRecord.PendingUploads == 0 && uploadsCounted &&
+                    PeekPipeStatsTextureUploadEmissions(&uploadsAfterAttach)) {
+                    EXPECT_GT(uploadsAfterAttach, uploadsBeforeAttach)
+                        << "the standing upload vanished from the record without Espryt uploading anything: "
+                           "the metadata respecify dropped it";
+                } else {
+                    EXPECT_EQ(earlyRecord.PendingUploads, 1u)
+                        << "the metadata respecify dropped the pending upload standing beside it";
+                }
+            }
+            const Image earlyAfter = DrawSampled(early);
+            ASSERT_EQ(FirstGLError(), GLenum(GL_NO_ERROR));
+            EXPECT_TRUE(Mostly(earlyAfter, "blue", "the upload that stood across a metadata respecify"));
+            glDeleteFramebuffers(1, &namedFbo);
+            GLuint cleanup = texture;
+            glDeleteTextures(1, &cleanup);
+            GLuint cleanupEarly = early;
+            glDeleteTextures(1, &cleanupEarly);
+        }
+
+    } // namespace
+} // namespace MGITest

MobileGL/MG_IntegrationTest/Scenarios/P4aSeamAuditScenario.cpp

@@ -0,0 +1,803 @@
+// MobileGL - MobileGL/MG_IntegrationTest/Scenarios/P4aSeamAuditScenario.cpp
+// Copyright (c) 2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+//
+// Scenario - THE FOUR SEAMS THE P4a FABLE SEAM AUDIT PROVED, each pinned by the public-GL sequence
+// (or the white-box reading) that was red on the tree the audit read and is green with its fix.
+//
+// The audit's rule, which every case here is an instance of: EVERY FIELD OF EVERY EMITTED RECORD
+// NAMES THE FRONTEND SETTER THAT CHANGES IT, AND THAT SETTER MOVES A COUNTER THE EMITTING BIT'S
+// SHUTTER READS. A record whose field has a setter no shutter sees is a stale record with nothing
+// to refuse - no census line, no Fatal, a wrong picture or a permanent silent fallback - which is
+// why none of the 80 scenarios before this file caught any of the four (Tracker.h carries the
+// record-field -> setter -> shutter table this file is the gate for).
+//
+//   F-3  set_framebuffer_state INLINES an attachment's format (D-C1) and a storage redefinition of
+//        an ATTACHED texture or renderbuffer moved nothing bit 11 read: Espryt's handle arm then
+//        answered its alpha-widening / snorm-clamp / integer masks from the stale copy. AND THE
+//        PRE-HANDLE ARM WAS NOT FRESH EITHER, which these cases found on the 0x1ff / 0 / pull
+//        lanes: a redefinition that keeps the driver id (mutable texture storage regenerated in
+//        place, a renderbuffer re-storaged in place) moves neither the framebuffer's frontend
+//        versions nor the backend-id generation the FBO memo reads, so SyncToBackend never
+//        re-ran and the masks stayed on both arms. The texture half is fixed on both arms OF A
+//        PUSH BUILD (an in-place regeneration now takes the same generation a re-mint takes -
+//        compiled under MOBILEGL_PIPE_PUSH because G1 keeps the pull library byte-identical to
+//        the P4a baseline, so the pull build keeps the pre-P4a hole until the fix lands on dev on
+//        its own and the texture cases decline by name there); the renderbuffer half only on the
+//        handle arm, where the resource record carries the re-storage - on the pre-handle arm a
+//        renderbuffer's twin is only ever reached from inside the FBO walk the memo skips (D-D2's
+//        documented hole, pre-P4a code), so that case asserts on the handle arm and declines by
+//        name elsewhere. Three cases, both directions, texture and renderbuffer. DirectGLES only:
+//        the masks are Espryt's substitution machinery.
+//   F-1  set_sampler_views is resolved for the PROGRAM IN USE and bit 12's shutter read no program
+//        input, so a glUseProgram alone never re-emitted it; E's record epoch (the two set serials)
+//        then kept the program-independent texture sync list from ever rebuilding, and a texture
+//        bound to an EMPTY slot under one program was never synced for the next. One case, both
+//        backends, red as a black quad.
+//   F-2  bit 14's plain-program arm mixed a per-program COUNTER two programs routinely share, so a
+//        program switch never re-emitted set_shader_images and the window stayed the previous
+//        program's - and E's SD-4 (a buffer image never reaching the record at all) is the same
+//        bit through the null -> program transition. One case, white-box, both backends run it.
+//   F-4  BindCurrentUnitSamplers' record arm looked a CONTENT-addressed CSO handle up in the
+//        IDENTITY-keyed twin registry: a miss on every draw, hidden because the pre-handle program
+//        pass bound the same values. One case, white-box: the unit's driver sampler must be the
+//        CSO's own twin.
+//
+// A WHITE-BOX READING THAT CANNOT BE TAKEN IS DECLINED BY NAME AND THE CASE CONTINUES with its
+// public-GL half (the shape TextureParamsWithoutASamplerViewScenario.cpp argues for): a pull
+// build, Magma, or a lane whose mask leaves Espryt's sampler family on its legacy arm has no
+// record arm to assert about, and skipping the whole case there would delete the public-GL
+// verdict those lanes carry. Every decline is printed and RecordProperty'd.
+
+#include <cstdint>
+#include <cstring>
+#include <iostream>
+#include <string>
+#include <vector>
+
+#include "../Harness/HeadlessGL.h"
+#include "../Harness/P4aSeamPeek.h"
+#include "../Harness/ScenarioFixture.h"
+
+#ifdef GLAPI
+#undef GLAPI
+#endif
+#define GL_GLEXT_PROTOTYPES
+#include <GL/gl.h>
+#include <GL/glcorearb.h>
+#undef GL_GLEXT_PROTOTYPES
+
+namespace MGITest {
+    namespace {
+
+        constexpr int kSize = 16;
+        constexpr int kInset = 2;
+
+        // No attributes: the quad's corners come from gl_VertexID, so a bare VAO is all a draw
+        // needs and no vertex-input state can enter any of the sequences below.
+        constexpr const char* kQuadVS = R"(#version 330 core
+void main() {
+    vec2 corner = vec2((gl_VertexID & 1) == 0 ? -1.0 : 1.0,
+                       (gl_VertexID & 2) == 0 ? -1.0 : 1.0);
+    gl_Position = vec4(corner, 0.0, 1.0);
+}
+)";
+
+        constexpr const char* kColorFS = R"(#version 330 core
+uniform vec4 uColor;
+out vec4 oColor;
+void main() { oColor = uColor; }
+)";
+
+        // texelFetch, so WHICH image the unit holds is the whole answer and no filter, wrap or
+        // completeness rule can explain a colour away.
+        constexpr const char* kFetchFS = R"(#version 330 core
+uniform sampler2D uTex;
+out vec4 oColor;
+void main() { oColor = texelFetch(uTex, ivec2(0, 0), 0); }
+)";
+
+        // texture() at (1.5, 1.5): outside the image on both axes, so the WRAP mode of whichever
+        // sampler applies - the unit's sampler object or the texture's built-in one - decides
+        // whether the texel or the border colour comes back.
+        constexpr const char* kOutsideSampleFS = R"(#version 330 core
+uniform sampler2D uTex;
+out vec4 oColor;
+void main() { oColor = texture(uTex, vec2(1.5, 1.5)); }
+)";
+
+        // F-2 / SD-4: two compute programs over BUFFER images (the SD-4 shape - the kind E's I2
+        // flip found never reached the record at all), the second naming one unit more than the
+        // first, and both image-unit counters equal (layout(binding) assigns the unit at link, so
+        // neither program ever moves it through glUniform1i).
+        constexpr const char* kOneBufferImageCS = R"(#version 430 core
+layout(local_size_x = 1) in;
+layout(binding = 0, r32ui) writeonly uniform uimageBuffer i0;
+void main() { imageStore(i0, 0, uvec4(7u, 0u, 0u, 0u)); }
+)";
+
+        constexpr const char* kTwoBufferImagesCS = R"(#version 430 core
+layout(local_size_x = 1) in;
+layout(binding = 0, r32ui) readonly uniform uimageBuffer i0;
+layout(binding = 1, r32ui) writeonly uniform uimageBuffer i1;
+void main() { imageStore(i1, 0, imageLoad(i0, 0) + uvec4(2u, 0u, 0u, 0u)); }
+)";
+
+        class P4aSeamAuditScenario : public ScenarioTest {
+        protected:
+            void SetUp() override {
+                ScenarioTest::SetUp();
+                if (!Ready()) return;
+                glGenVertexArrays(1, &m_vao);
+                glBindVertexArray(m_vao);
+                glDisable(GL_BLEND);
+                glDisable(GL_SCISSOR_TEST);
+                glDisable(GL_DEPTH_TEST);
+                glColorMask(GL_TRUE, GL_TRUE, GL_TRUE, GL_TRUE);
+                while (glGetError() != GL_NO_ERROR) {
+                }
+            }
+
+            void TearDown() override {
+                if (!Ready()) return;
+                glUseProgram(0);
+                glBindVertexArray(0);
+                if (m_vao != 0) glDeleteVertexArrays(1, &m_vao);
+                glBindFramebuffer(GL_FRAMEBUFFER, 0);
+                while (glGetError() != GL_NO_ERROR) {
+                }
+            }
+
+            // The F-3 cases are about Espryt's four cross-object masks, which are its own
+            // substitution machinery (three-channel widening, SNORM/UNORM clamp, integer outputs);
+            // Magma answers the same GL questions on its own terms, so a verdict there would pin
+            // a coincidence - the same reason SnormAttachment and ThreeChannelAttachment skip.
+            // Marks the case skipped; the caller tests IsSkipped() and returns (GTEST_SKIP is a
+            // void statement, so it cannot return the verdict itself).
+            void SkipUnlessEspryt(const char* what) {
+                if (Gl().BackendName() == "DirectGLES") return;
+                GTEST_SKIP() << what << " is a DirectGLES handle-arm seam; backend is " << Gl().BackendName();
+            }
+
+            static void DrawQuad() { glDrawArrays(GL_TRIANGLE_STRIP, 0, 4); }
+
+            // One pixel's RGBA as floats, from the currently bound READ framebuffer.
+            static void ReadPixelFloat(int x, int y, float out[4]) {
+                out[0] = out[1] = out[2] = out[3] = -1.0f;
+                glReadPixels(x, y, 1, 1, GL_RGBA, GL_FLOAT, out);
+            }
+
+            // The white-box gate shared by F-2 and F-4: true when Espryt's sampler family is on
+            // its handle arm in this process, so the applier's unit sets are consumed and an
+            // assertion about them can only be red for its own reason. Prints the decline.
+            bool SamplerHandleArmIsLive(const char* what) {
+                bool live = false;
+                std::string why;
+                if (!PeekEsprytSamplerHandleArmIsLive(&live)) {
+                    why = "the reading cannot be taken here (a pull build, Android, or a backend that "
+                          "is not DirectGLES)";
+                } else if (!live) {
+                    why = "Espryt's sampler family runs its legacy arm in this process "
+                          "(MOBILEGL_PIPE_PUSH leaves bit 11 clear or refuses it)";
+                }
+                if (why.empty()) return true;
+                std::cout << "[ P4aSeamAudit ] white-box reading DECLINED for " << what << ": " << why
+                          << "; the public-GL half of the case still runs" << std::endl;
+                RecordProperty("p4a_seam_white_box", "declined");
+                RecordProperty("p4a_seam_white_box_reason", why);
+                return false;
+            }
+
+            // A 2x2 RGBA8 texture filled with one colour, NEAREST, single level - complete under
+            // every rule, so nothing about completeness can enter the F-1 and F-4 sequences.
+            static GLuint MakeSolidTexture2D(std::uint8_t r, std::uint8_t g, std::uint8_t b) {
+                std::uint8_t texels[2 * 2 * 4];
+                for (int i = 0; i < 4; ++i) {
+                    texels[i * 4 + 0] = r;
+                    texels[i * 4 + 1] = g;
+                    texels[i * 4 + 2] = b;
+                    texels[i * 4 + 3] = 255;
+                }
+                GLuint texture = 0;
+                glGenTextures(1, &texture);
+                glBindTexture(GL_TEXTURE_2D, texture);
+                glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, 2, 2, 0, GL_RGBA, GL_UNSIGNED_BYTE, texels);
+                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+                return texture;
+            }
+
+            bool ComputeImagesAreUsable() const {
+                GLint maxImageUnits = 0;
+                glGetIntegerv(GL_MAX_IMAGE_UNITS, &maxImageUnits);
+                GLint maxComputeImageUniforms = 0;
+                glGetIntegerv(GL_MAX_COMPUTE_IMAGE_UNIFORMS, &maxComputeImageUniforms);
+                GLint maxBufferSize = 0;
+                glGetIntegerv(GL_MAX_TEXTURE_BUFFER_SIZE, &maxBufferSize);
+                while (glGetError() != GL_NO_ERROR) {
+                }
+                return maxImageUnits >= 2 && maxComputeImageUniforms >= 2 && maxBufferSize >= 4;
+            }
+
+            static GLuint MakeComputeProgram(const char* source, std::string* outError) {
+                const GLuint shader = glCreateShader(GL_COMPUTE_SHADER);
+                glShaderSource(shader, 1, &source, nullptr);
+                glCompileShader(shader);
+                GLint compiled = GL_FALSE;
+                glGetShaderiv(shader, GL_COMPILE_STATUS, &compiled);
+                if (compiled == GL_FALSE) {
+                    char log[2048] = {};
+                    glGetShaderInfoLog(shader, sizeof(log) - 1, nullptr, log);
+                    *outError = std::string("compute shader did not compile: ") + log;
+                    glDeleteShader(shader);
+                    return 0;
+                }
+                const GLuint program = glCreateProgram();
+                glAttachShader(program, shader);
+                glLinkProgram(program);
+                glDeleteShader(shader);
+                GLint linked = GL_FALSE;
+                glGetProgramiv(program, GL_LINK_STATUS, &linked);
+                if (linked == GL_FALSE) {
+                    char log[2048] = {};
+                    glGetProgramInfoLog(program, sizeof(log) - 1, nullptr, log);
+                    *outError = std::string("compute program did not link: ") + log;
+                    glDeleteProgram(program);
+                    return 0;
+                }
+                return program;
+            }
+
+            // An R32UI buffer texture over a fresh 4-texel buffer, every texel `fill`.
+            static GLuint MakeBufferTexture(GLuint* outBuffer, GLuint fill) {
+                const GLuint texels[4] = {fill, fill, fill, fill};
+                glGenBuffers(1, outBuffer);
+                glBindBuffer(GL_TEXTURE_BUFFER, *outBuffer);
+                glBufferData(GL_TEXTURE_BUFFER, sizeof(texels), texels, GL_DYNAMIC_COPY);
+                GLuint texture = 0;
+                glGenTextures(1, &texture);
+                glBindTexture(GL_TEXTURE_BUFFER, texture);
+                glTexBuffer(GL_TEXTURE_BUFFER, GL_R32UI, *outBuffer);
+                return texture;
+            }
+
+            static GLuint ReadBufferTexel0(GLuint buffer) {
+                GLuint value = 0xFFFFFFFFu;
+                glBindBuffer(GL_TEXTURE_BUFFER, buffer);
+                glGetBufferSubData(GL_TEXTURE_BUFFER, 0, sizeof(value), &value);
+                return value;
+            }
+
+            GLuint m_vao = 0;
+        };
+
+        // -----------------------------------------------------------------------------------
+        // F-3: a storage redefinition WHILE ATTACHED reaches the framebuffer record
+        // -----------------------------------------------------------------------------------
+        //
+        // GL_SRGB8 is a format Espryt can only render into through its three-channel widening
+        // (llvmpipe reports INCOMPLETE_ATTACHMENT for it natively - ThreeChannelAttachmentScenario
+        // measured the table), so its draw buffer carries the alpha-widened mask: every draw has its
+        // alpha masked off so the stored alpha stays at the 1.0 a three-channel format implies.
+        // Redefine the same attached texture as GL_SRGB8_ALPHA8 and the application owns alpha
+        // again - the mask must clear. On the tree the audit read the record still said SRGB8, the
+        // handle arm kept masking, and the 0.25 this case draws never reached the storage; on the
+        // pre-handle arm the twin regenerated the (mutable) storage on the same driver id, nothing
+        // the FBO memo reads moved, and the masks stayed the same way.
+
+        TEST_F(P4aSeamAuditScenario, ATextureRespecifiedWhileAttachedReachesTheFramebufferRecord) {
+            if (!Ready()) return;
+            SkipUnlessEspryt("F-3");
+            if (IsSkipped()) return;
+
+            std::string error;
+            const GLuint program = CompileProgram(kQuadVS, kColorFS, &error);
+            ASSERT_NE(program, 0u) << error;
+            const GLint colorLocation = glGetUniformLocation(program, "uColor");
+            ASSERT_GE(colorLocation, 0);
+
+            GLuint texture = 0;
+            glGenTextures(1, &texture);
+            glBindTexture(GL_TEXTURE_2D, texture);
+            glTexImage2D(GL_TEXTURE_2D, 0, GL_SRGB8, kSize, kSize, 0, GL_RGB, GL_UNSIGNED_BYTE, nullptr);
+            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+            ASSERT_EQ(FirstGLError(), 0u) << "the SRGB8 texture was refused";
+
+            GLuint fbo = 0;
+            glGenFramebuffers(1, &fbo);
+            glBindFramebuffer(GL_FRAMEBUFFER, fbo);
+            glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, texture, 0);
+            ASSERT_EQ(glCheckFramebufferStatus(GL_FRAMEBUFFER), static_cast<GLenum>(GL_FRAMEBUFFER_COMPLETE))
+                << "an SRGB8 colour attachment must be complete (natively or through the widening)";
+            glViewport(0, 0, kSize, kSize);
+            glUseProgram(program);
+            glUniform4f(colorLocation, 0.0f, 1.0f, 0.0f, 0.25f);
+
+            // Phase 1: the three-channel format. Whatever the draw writes, GL reports alpha 1.0.
+            glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
+            glClear(GL_COLOR_BUFFER_BIT);
+            DrawQuad();
+            float pixel[4];
+            glReadBuffer(GL_COLOR_ATTACHMENT0);
+            ReadPixelFloat(kSize / 2, kSize / 2, pixel);
+            EXPECT_NEAR(pixel[3], 1.0f, 0.02f) << "a three-channel attachment reports alpha 1.0";
+
+            // Phase 2: THE RESPECIFY, while attached, with no re-attach and no rebind of the FBO.
+            // The only thing that moves between the two draws is the texture's storage.
+            glBindTexture(GL_TEXTURE_2D, texture);
+            glTexImage2D(GL_TEXTURE_2D, 0, GL_SRGB8_ALPHA8, kSize, kSize, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
+            ASSERT_EQ(FirstGLError(), 0u) << "the respecify to SRGB8_ALPHA8 was refused";
+            ASSERT_EQ(glCheckFramebufferStatus(GL_FRAMEBUFFER), static_cast<GLenum>(GL_FRAMEBUFFER_COMPLETE));
+
+            glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
+            glClear(GL_COLOR_BUFFER_BIT);
+            DrawQuad();
+            ReadPixelFloat(kSize / 2, kSize / 2, pixel);
+            EXPECT_NEAR(pixel[1], 1.0f, 0.05f) << "the draw did not land at all";
+            // PUSH BUILDS ONLY, EVERY ARM OF THEM. The pre-handle half of the fix (an in-place
+            // regeneration takes the backend-id generation a re-mint takes) is Espryt code the
+            // pull build would share, and G1 keeps the pull library byte-identical to the P4a
+            // baseline - so it is compiled under MOBILEGL_PIPE_PUSH and the pull build keeps the
+            // pre-P4a hole until the same lines land on dev on their own. The peek returns true
+            // exactly where it could look, which for a case that already skipped off Espryt means
+            // "a push build"; what it writes (is the handle arm live) does not matter here.
+            bool framebufferArmLive = false;
+            if (PeekEsprytFramebufferHandleArmIsLive(&framebufferArmLive)) {
+                EXPECT_NEAR(pixel[3], 0.25f, 0.02f)
+                    << "the draw's alpha never reached a four-channel attachment: the framebuffer record "
+                       "(handle arm) or the FBO twin's memo (pre-handle arm) still describes the "
+                       "three-channel storage the texture was attached with, so alpha stayed masked off (F-3)";
+            } else {
+                std::cout << "[ P4aSeamAudit ] texture respecify verdict DECLINED on the pull build (the "
+                             "in-place regeneration bump is push-only by G1); alpha read "
+                          << pixel[3] << std::endl;
+                RecordProperty("p4a_seam_white_box", "declined");
+                RecordProperty("p4a_seam_white_box_reason", "texture respecify: pull build (G1)");
+            }
+
+            glBindFramebuffer(GL_FRAMEBUFFER, 0);
+            glDeleteFramebuffers(1, &fbo);
+            glDeleteTextures(1, &texture);
+            glDeleteProgram(program);
+            EXPECT_EQ(FirstGLError(), 0u) << GLErrorName(FirstGLError());
+        }
+
+        // The renderbuffer twin. A renderbuffer's three storage setters bump no version at all:
+        // D-D2 closed the RESOURCE record by emitting from the entry point and left the framebuffer
+        // record - and with it the masks - describing the storage it was attached with.
+        TEST_F(P4aSeamAuditScenario, ARenderbufferRestoragedWhileAttachedReachesTheFramebufferRecord) {
+            if (!Ready()) return;
+            SkipUnlessEspryt("F-3");
+            if (IsSkipped()) return;
+
+            std::string error;
+            const GLuint program = CompileProgram(kQuadVS, kColorFS, &error);
+            ASSERT_NE(program, 0u) << error;
+            const GLint colorLocation = glGetUniformLocation(program, "uColor");
+            ASSERT_GE(colorLocation, 0);
+
+            GLuint renderbuffer = 0;
+            glGenRenderbuffers(1, &renderbuffer);
+            glBindRenderbuffer(GL_RENDERBUFFER, renderbuffer);
+            glRenderbufferStorage(GL_RENDERBUFFER, GL_SRGB8, kSize, kSize);
+            ASSERT_EQ(FirstGLError(), 0u) << "the SRGB8 renderbuffer was refused";
+
+            GLuint fbo = 0;
+            glGenFramebuffers(1, &fbo);
+            glBindFramebuffer(GL_FRAMEBUFFER, fbo);
+            glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, renderbuffer);
+            ASSERT_EQ(glCheckFramebufferStatus(GL_FRAMEBUFFER), static_cast<GLenum>(GL_FRAMEBUFFER_COMPLETE))
+                << "an SRGB8 renderbuffer attachment must be complete (natively or through the widening)";
+            glViewport(0, 0, kSize, kSize);
+            glUseProgram(program);
+            glUniform4f(colorLocation, 0.0f, 1.0f, 0.0f, 0.25f);
+
+            glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
+            glClear(GL_COLOR_BUFFER_BIT);
+            DrawQuad();
+            float pixel[4];
+            glReadBuffer(GL_COLOR_ATTACHMENT0);
+            ReadPixelFloat(kSize / 2, kSize / 2, pixel);
+            EXPECT_NEAR(pixel[3], 1.0f, 0.02f) << "a three-channel attachment reports alpha 1.0";
+
+            // THE RE-STORAGE, while attached.
+            glBindRenderbuffer(GL_RENDERBUFFER, renderbuffer);
+            glRenderbufferStorage(GL_RENDERBUFFER, GL_SRGB8_ALPHA8, kSize, kSize);
+            ASSERT_EQ(FirstGLError(), 0u) << "the re-storage to SRGB8_ALPHA8 was refused";
+            ASSERT_EQ(glCheckFramebufferStatus(GL_FRAMEBUFFER), static_cast<GLenum>(GL_FRAMEBUFFER_COMPLETE));
+
+            glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
+            glClear(GL_COLOR_BUFFER_BIT);
+            DrawQuad();
+            ReadPixelFloat(kSize / 2, kSize / 2, pixel);
+            EXPECT_NEAR(pixel[1], 1.0f, 0.05f) << "the draw did not land at all";
+            // THE HANDLE ARM ONLY. On the pre-handle arm a renderbuffer's twin is reached only from
+            // inside the FBO walk, and nothing that walk's memo reads moves on glRenderbufferStorage
+            // - the frontend setters bump no version (D-D2), no framebuffer version sees them, and
+            // the twin that would bump the backend generation is exactly what the memo skips. That
+            // is pre-P4a code and D-D2's documented hole; the resource record is what closes it,
+            // so the verdict is taken where the record is consumed and declined by name elsewhere
+            // (measured: alpha 1.0 on the pull build and at 0x1ff / 0, the mask of the storage the
+            // renderbuffer was attached with).
+            bool framebufferArmLive = false;
+            if (PeekEsprytFramebufferHandleArmIsLive(&framebufferArmLive) && framebufferArmLive) {
+                EXPECT_NEAR(pixel[3], 0.25f, 0.02f)
+                    << "the draw's alpha never reached the four-channel renderbuffer: the framebuffer "
+                       "record still describes the storage it was attached with (F-3)";
+            } else {
+                std::cout << "[ P4aSeamAudit ] renderbuffer re-storage verdict DECLINED on the pre-handle arm "
+                             "(D-D2's documented hole: no frontend version and no backend generation moves on a "
+                             "renderbuffer re-storage until the FBO walk the memo skips); alpha read "
+                          << pixel[3] << std::endl;
+                RecordProperty("p4a_seam_white_box", "declined");
+                RecordProperty("p4a_seam_white_box_reason", "renderbuffer re-storage: pre-handle arm (D-D2)");
+            }
+
+            glBindFramebuffer(GL_FRAMEBUFFER, 0);
+            glDeleteFramebuffers(1, &fbo);
+            glDeleteRenderbuffers(1, &renderbuffer);
+            glDeleteProgram(program);
+            EXPECT_EQ(FirstGLError(), 0u) << GLErrorName(FirstGLError());
+        }
+
+        // The mirror direction, four channels -> three, and it needs the driver to READ the stored
+        // alpha because the readback fixup (which consults the frontend) would hide it: after the
+        // respecify to SRGB8 the widening discipline has to hold - the clear puts 1.0 into the
+        // carrier's alpha and the draw is masked away from it - so a GL_DST_ALPHA blend of white sees
+        // 1.0. On a stale record the draw wrote its 0.25 into the carrier and the blend saw that.
+        TEST_F(P4aSeamAuditScenario, ATextureRespecifiedToThreeChannelsWhileAttachedReachesTheFramebufferRecord) {
+            if (!Ready()) return;
+            SkipUnlessEspryt("F-3");
+            if (IsSkipped()) return;
+
+            std::string error;
+            const GLuint program = CompileProgram(kQuadVS, kColorFS, &error);
+            ASSERT_NE(program, 0u) << error;
+            const GLint colorLocation = glGetUniformLocation(program, "uColor");
+            ASSERT_GE(colorLocation, 0);
+
+            GLuint texture = 0;
+            glGenTextures(1, &texture);
+            glBindTexture(GL_TEXTURE_2D, texture);
+            glTexImage2D(GL_TEXTURE_2D, 0, GL_SRGB8_ALPHA8, kSize, kSize, 0, GL_RGBA, GL_UNSIGNED_BYTE, nullptr);
+            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+            ASSERT_EQ(FirstGLError(), 0u) << "the SRGB8_ALPHA8 texture was refused";
+
+            GLuint fbo = 0;
+            glGenFramebuffers(1, &fbo);
+            glBindFramebuffer(GL_FRAMEBUFFER, fbo);
+            glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, texture, 0);
+            ASSERT_EQ(glCheckFramebufferStatus(GL_FRAMEBUFFER), static_cast<GLenum>(GL_FRAMEBUFFER_COMPLETE));
+            glViewport(0, 0, kSize, kSize);
+            glUseProgram(program);
+
+            // Phase 1: four channels, the application owns alpha.
+            glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
+            glClear(GL_COLOR_BUFFER_BIT);
+            glUniform4f(colorLocation, 0.0f, 1.0f, 0.0f, 0.25f);
+            DrawQuad();
+            float pixel[4];
+            glReadBuffer(GL_COLOR_ATTACHMENT0);
+            ReadPixelFloat(kSize / 2, kSize / 2, pixel);
+            EXPECT_NEAR(pixel[3], 0.25f, 0.02f) << "a four-channel attachment stores the draw's alpha";
+
+            // Phase 2: THE RESPECIFY to three channels, while attached.
+            glBindTexture(GL_TEXTURE_2D, texture);
+            glTexImage2D(GL_TEXTURE_2D, 0, GL_SRGB8, kSize, kSize, 0, GL_RGB, GL_UNSIGNED_BYTE, nullptr);
+            ASSERT_EQ(FirstGLError(), 0u) << "the respecify to SRGB8 was refused";
+            ASSERT_EQ(glCheckFramebufferStatus(GL_FRAMEBUFFER), static_cast<GLenum>(GL_FRAMEBUFFER_COMPLETE));
+
+            glDisable(GL_BLEND);
+            glClearColor(0.0f, 0.0f, 0.0f, 0.0f);
+            glClear(GL_COLOR_BUFFER_BIT);
+            glUniform4f(colorLocation, 0.0f, 1.0f, 0.0f, 0.25f);
+            DrawQuad();
+            // dst = stored alpha; src factor GL_DST_ALPHA, dst factor GL_ZERO, source white =>
+            // the colour becomes (storedAlpha, storedAlpha, storedAlpha) - ThreeChannelAttachment's
+            // own probe, which nothing on the readback path can doctor.
+            glEnable(GL_BLEND);
+            glBlendFunc(GL_DST_ALPHA, GL_ZERO);
+            glUniform4f(colorLocation, 1.0f, 1.0f, 1.0f, 1.0f);
+            DrawQuad();
+            glDisable(GL_BLEND);
+            ReadPixelFloat(kSize / 2, kSize / 2, pixel);
+            // PUSH BUILDS ONLY, EVERY ARM OF THEM (the mirror). The pre-handle half of the fix (an in-place
+            // regeneration takes the backend-id generation a re-mint takes) is Espryt code the
+            // pull build would share, and G1 keeps the pull library byte-identical to the P4a
+            // baseline - so it is compiled under MOBILEGL_PIPE_PUSH and the pull build keeps the
+            // pre-P4a hole until the same lines land on dev on their own. The peek returns true
+            // exactly where it could look, which for a case that already skipped off Espryt means
+            // "a push build"; what it writes (is the handle arm live) does not matter here.
+            bool framebufferArmLive = false;
+            if (PeekEsprytFramebufferHandleArmIsLive(&framebufferArmLive)) {
+                EXPECT_NEAR(pixel[0], 1.0f, 0.05f)
+                    << "GL_DST_ALPHA read the stored alpha of a three-channel attachment and it was not "
+                       "1.0: the framebuffer record (handle arm) or the FBO twin's memo (pre-handle arm) "
+                       "still describes the four-channel storage the texture was attached with, so the "
+                       "draw was let write alpha (F-3, mirror)";
+            } else {
+                std::cout << "[ P4aSeamAudit ] three-channel respecify verdict DECLINED on the pull build (the "
+                             "in-place regeneration bump is push-only by G1); red read "
+                          << pixel[0] << std::endl;
+                RecordProperty("p4a_seam_white_box", "declined");
+                RecordProperty("p4a_seam_white_box_reason", "three-channel respecify: pull build (G1)");
+            }
+
+            glBindFramebuffer(GL_FRAMEBUFFER, 0);
+            glDeleteFramebuffers(1, &fbo);
+            glDeleteTextures(1, &texture);
+            glDeleteProgram(program);
+            EXPECT_EQ(FirstGLError(), 0u) << GLErrorName(FirstGLError());
+        }
+
+        // -----------------------------------------------------------------------------------
+        // F-1 / F-1b: a program switch re-resolves the view set, and the texture sync list with it
+        // -----------------------------------------------------------------------------------
+        //
+        // The sequence the audit named, and every step of it is ordinary: two programs sampling two
+        // different units, a texture bound to a unit's EMPTY 2D slot - the unit was already touched
+        // through another target, so the high-water mark does not move - while a program that does
+        // not sample it is in use, then the switch to the one that does. Nothing between the two
+        // draws touches a parameter, a level or a populated slot, which is exactly what leaves the
+        // record epoch - and the program-independent texture sync list keyed on it - unmoved on
+        // the tree the audit read: the second program sampled an unbound unit and drew black.
+        TEST_F(P4aSeamAuditScenario, ATextureBoundToAnEmptySlotUnderOneProgramIsSampledByTheNext) {
+            if (!Ready()) return;
+
+            std::string error;
+            const GLuint first = CompileProgram(kQuadVS, kFetchFS, &error);
+            ASSERT_NE(first, 0u) << error;
+            const GLuint second = CompileProgram(kQuadVS, kFetchFS, &error);
+            ASSERT_NE(second, 0u) << error;
+            glUseProgram(first);
+            glUniform1i(glGetUniformLocation(first, "uTex"), 0);
+            glUseProgram(second);
+            glUniform1i(glGetUniformLocation(second, "uTex"), 1);
+            glUseProgram(0);
+
+            // Every texture exists, complete, with its parameters set, BEFORE the first draw: a
+            // parameter or a level defined between the two draws would move the sampling-resolution
+            // generation and rescue the list by accident.
+            const GLuint red = MakeSolidTexture2D(255, 0, 0);
+            const GLuint green = MakeSolidTexture2D(0, 255, 0);
+            GLuint touch3D = 0;
+            glGenTextures(1, &touch3D);
+            glBindTexture(GL_TEXTURE_3D, touch3D);
+            const std::uint8_t blue[2 * 2 * 2 * 4] = {0, 0, 255, 255, 0, 0, 255, 255, 0, 0, 255, 255, 0, 0, 255, 255,
+                                                     0, 0, 255, 255, 0, 0, 255, 255, 0, 0, 255, 255, 0, 0, 255, 255};
+            glTexImage3D(GL_TEXTURE_3D, 0, GL_RGBA8, 2, 2, 2, 0, GL_RGBA, GL_UNSIGNED_BYTE, blue);
+            glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+            glTexParameteri(GL_TEXTURE_3D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+            glBindTexture(GL_TEXTURE_3D, 0);
+            glBindTexture(GL_TEXTURE_2D, 0);
+            ASSERT_EQ(FirstGLError(), 0u) << "texture setup left a GL error behind";
+
+            ColorFbo target = MakeColorFbo(kSize, kSize);
+            ASSERT_NE(target.fbo, 0u);
+            BindFbo(target);
+            glBindVertexArray(m_vao);
+
+            // Unit 1 is TOUCHED through its 3D slot; its 2D slot stays empty. Unit 0 holds red.
+            // The first program is in use BEFORE the first verb (the clear), so the very first
+            // view set that goes out is already resolved for it - measured: with no program in
+            // use at the clear the first set is [null, null], and the bind below then re-resolves
+            // to [red, null], a DIFFERENT set that moves the serial and rescues the case by
+            // accident.
+            glActiveTexture(GL_TEXTURE1);
+            glBindTexture(GL_TEXTURE_3D, touch3D);
+            glActiveTexture(GL_TEXTURE0);
+            glBindTexture(GL_TEXTURE_2D, red);
+            glUseProgram(first);
+            ClearTo(0.0f, 0.0f, 1.0f, 1.0f);
+            DrawQuad();
+
+            // THE BIND ONTO THE EMPTY SLOT, under a program that does not sample unit 1, and a
+            // draw with THAT program so the bind's own re-resolution of the view set happens under
+            // it (the bind generation fires bit 12 at the next verb; a switch inside the same verb
+            // gap would let that fire resolve under the second program by accident) ...
+            glActiveTexture(GL_TEXTURE1);
+            glBindTexture(GL_TEXTURE_2D, green);
+            glActiveTexture(GL_TEXTURE0);
+            DrawQuad();
+            // ... and THE SWITCH to the one that does sample it. No other state moves.
+            glUseProgram(second);
+            DrawQuad();
+            EXPECT_EQ(FirstGLError(), 0u) << "the two draws left a GL error behind";
+
+            const Image image = ReadPixels(kSize, kSize);
+            ASSERT_FALSE(image.Empty());
+            EXPECT_TRUE(RegionIsMostly(image, kInset, kSize - 1 - kInset, kInset, kSize - 1 - kInset, "green", 0.0,
+                                       "the draw after the program switch"))
+                << "black means the second program sampled an unbound unit: the texture bound to the "
+                   "empty slot was never synced because the view set - and E's record epoch with it - "
+                   "did not move on the program switch (F-1 / F-1b); red means the first program's "
+                   "set was still in force";
+
+            glActiveTexture(GL_TEXTURE1);
+            glBindTexture(GL_TEXTURE_2D, 0);
+            glBindTexture(GL_TEXTURE_3D, 0);
+            glActiveTexture(GL_TEXTURE0);
+            glBindTexture(GL_TEXTURE_2D, 0);
+            glUseProgram(0);
+            DestroyColorFbo(target);
+            glDeleteTextures(1, &red);
+            glDeleteTextures(1, &green);
+            glDeleteTextures(1, &touch3D);
+            glDeleteProgram(first);
+            glDeleteProgram(second);
+            EXPECT_EQ(FirstGLError(), 0u) << GLErrorName(FirstGLError());
+        }
+
+        // -----------------------------------------------------------------------------------
+        // F-2 / SD-4: the image window follows the program, through buffer images
+        // -----------------------------------------------------------------------------------
+        //
+        // Public-GL half: both dispatches store what they should (every arm passes this - the
+        // server's window/high-water union takes the pre-handle bind for a unit the record does
+        // not cover, which is exactly why the seam was silent). White-box half, on Espryt's handle
+        // arm: after the first dispatch set_shader_images must have arrived with a window of ONE
+        // unit (SD-4: on the tree the audit read a buffer image never reached the record at all -
+        // the null -> program transition moved nothing bit 14 read), and after the switch to the
+        // program naming two units the window must be TWO (F-2: the two programs' image-unit
+        // counters are equal, so the switch alone moved nothing either).
+        TEST_F(P4aSeamAuditScenario, AProgramSwitchWithEqualImageUnitCountersMovesTheImageWindow) {
+            if (!Ready()) return;
+            if (!ComputeImagesAreUsable()) GTEST_SKIP() << "no compute image units / buffer textures on this host";
+
+            std::string error;
+            const GLuint one = MakeComputeProgram(kOneBufferImageCS, &error);
+            ASSERT_NE(one, 0u) << error;
+            const GLuint two = MakeComputeProgram(kTwoBufferImagesCS, &error);
+            ASSERT_NE(two, 0u) << error;
+
+            GLuint buffer0 = 0;
+            GLuint buffer1 = 0;
+            const GLuint image0 = MakeBufferTexture(&buffer0, 0u);
+            const GLuint image1 = MakeBufferTexture(&buffer1, 0u);
+            ASSERT_EQ(FirstGLError(), 0u) << "buffer texture setup left a GL error behind";
+
+            // Both units bound BEFORE any dispatch, so the bind generation does not move between
+            // the two dispatches and the only thing that changes is the program in use.
+            glBindImageTexture(0, image0, 0, GL_FALSE, 0, GL_READ_WRITE, GL_R32UI);
+            glBindImageTexture(1, image1, 0, GL_FALSE, 0, GL_READ_WRITE, GL_R32UI);
+            ASSERT_EQ(FirstGLError(), 0u) << "binding the buffer images left a GL error behind";
+
+            const bool whiteBox = SamplerHandleArmIsLive("F-2 / SD-4");
+
+            glUseProgram(one);
+            glDispatchCompute(1, 1, 1);
+            glMemoryBarrier(GL_ALL_BARRIER_BITS);
+            EXPECT_EQ(FirstGLError(), 0u) << "the first dispatch leaked a GL error";
+            if (whiteBox) {
+                PipeShaderImageWindowPeek window{};
+                ASSERT_TRUE(PeekPipeShaderImageWindow(&window));
+                EXPECT_EQ(window.Start, 0u);
+                EXPECT_EQ(window.Count, 1u)
+                    << "set_shader_images never arrived for a program whose only image is a BUFFER "
+                       "image (SD-4): the null -> program transition moved nothing bit 14 read";
+            }
+
+            glUseProgram(two);
+            glDispatchCompute(1, 1, 1);
+            glMemoryBarrier(GL_ALL_BARRIER_BITS);
+            EXPECT_EQ(FirstGLError(), 0u) << "the second dispatch leaked a GL error";
+            if (whiteBox) {
+                PipeShaderImageWindowPeek window{};
+                ASSERT_TRUE(PeekPipeShaderImageWindow(&window));
+                EXPECT_EQ(window.Start, 0u);
+                EXPECT_EQ(window.Count, 2u)
+                    << "the image window did not follow the program switch: two programs with equal "
+                       "image-unit counters, and bit 14 mixed only the counter (F-2)";
+            }
+
+            EXPECT_EQ(ReadBufferTexel0(buffer0), 7u) << "the first program's store did not land";
+            EXPECT_EQ(ReadBufferTexel0(buffer1), 9u) << "the second program's store did not land";
+
+            glBindImageTexture(0, 0, 0, GL_FALSE, 0, GL_READ_ONLY, GL_R32UI);
+            glBindImageTexture(1, 0, 0, GL_FALSE, 0, GL_READ_ONLY, GL_R32UI);
+            glBindBuffer(GL_TEXTURE_BUFFER, 0);
+            glBindTexture(GL_TEXTURE_BUFFER, 0);
+            glUseProgram(0);
+            glDeleteProgram(one);
+            glDeleteProgram(two);
+            glDeleteTextures(1, &image0);
+            glDeleteTextures(1, &image1);
+            glDeleteBuffers(1, &buffer0);
+            glDeleteBuffers(1, &buffer1);
+            EXPECT_EQ(FirstGLError(), 0u) << GLErrorName(FirstGLError());
+        }
+
+        // -----------------------------------------------------------------------------------
+        // F-4: the unit's driver sampler is the CSO's own twin on the handle arm
+        // -----------------------------------------------------------------------------------
+        //
+        // Public-GL half: a glBindSampler'd object whose wrap differs from the texture's built-in
+        // sampler wins (GL 4.6 core 8.10) - every arm passes this, because the pre-handle program
+        // pass bound the object through its identity twin. White-box half, on Espryt's handle arm:
+        // the sampler the unit carries on the driver must be the twin Espryt holds AT THE CSO
+        // HANDLE bind_sampler_states named for the unit. On the tree the audit read that twin did
+        // not exist - the handle is content-addressed, the registry's twins were minted off
+        // lifetime ids - so the record arm bound nothing on every draw.
+        TEST_F(P4aSeamAuditScenario, ABoundSamplerObjectIsDrivenThroughItsCsoTwinOnTheHandleArm) {
+            if (!Ready()) return;
+
+            std::string error;
+            const GLuint program = CompileProgram(kQuadVS, kOutsideSampleFS, &error);
+            ASSERT_NE(program, 0u) << error;
+
+            // The texture's built-in sampler REPEATS, so (1.5, 1.5) reads the red texel through it;
+            // the sampler object CLAMPS TO A WHITE BORDER, so the same coordinate reads white
+            // through it. White is a Vulkan palette border colour, so Magma needs no extension.
+            const GLuint red = MakeSolidTexture2D(255, 0, 0);
+            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_REPEAT);
+            glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_REPEAT);
+            GLuint sampler = 0;
+            glGenSamplers(1, &sampler);
+            glSamplerParameteri(sampler, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+            glSamplerParameteri(sampler, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+            glSamplerParameteri(sampler, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_BORDER);
+            glSamplerParameteri(sampler, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_BORDER);
+            const GLfloat white[4] = {1.0f, 1.0f, 1.0f, 1.0f};
+            glSamplerParameterfv(sampler, GL_TEXTURE_BORDER_COLOR, white);
+            ASSERT_EQ(FirstGLError(), 0u) << "sampler setup left a GL error behind";
+
+            ColorFbo target = MakeColorFbo(kSize, kSize);
+            ASSERT_NE(target.fbo, 0u);
+            BindFbo(target);
+            glBindVertexArray(m_vao);
+            glActiveTexture(GL_TEXTURE0);
+            glBindTexture(GL_TEXTURE_2D, red);
+            glBindSampler(0, sampler);
+            glUseProgram(program);
+            glUniform1i(glGetUniformLocation(program, "uTex"), 0);
+            ClearTo(0.0f, 0.0f, 1.0f, 1.0f);
+            DrawQuad();
+            EXPECT_EQ(FirstGLError(), 0u) << "the draw left a GL error behind";
+
+            const Image image = ReadPixels(kSize, kSize);
+            ASSERT_FALSE(image.Empty());
+            EXPECT_TRUE(RegionIsMostly(image, kInset, kSize - 1 - kInset, kInset, kSize - 1 - kInset, "white", 0.0,
+                                       "the draw through the bound sampler object"))
+                << "red means the texture's own REPEAT sampler applied instead of the bound object's "
+                   "CLAMP_TO_BORDER";
+
+            if (SamplerHandleArmIsLive("F-4")) {
+                EsprytUnitSamplerPeek peek{};
+                ASSERT_TRUE(PeekEsprytUnitSampler(0, sampler, &peek));
+                std::cout << "[ P4aSeamAudit ] white-box: unit 0 driver sampler " << peek.BoundSamplerId
+                          << ", bind_sampler_states handle {" << peek.CsoHandleSlot << ", " << peek.CsoHandleGen
+                          << "} inside window " << (peek.UnitInsideWindow ? "yes" : "no") << ", CSO twin "
+                          << peek.CsoTwinSamplerId << ", identity twin " << peek.IdentityTwinSamplerId << std::endl;
+                EXPECT_TRUE(peek.UnitInsideWindow) << "bind_sampler_states did not describe unit 0";
+                EXPECT_NE(peek.CsoHandleSlot, 0u) << "bind_sampler_states names no CSO for a unit that carries "
+                                                     "a sampler object";
+                EXPECT_NE(peek.CsoTwinSamplerId, 0u)
+                    << "Espryt holds no twin at the CSO handle bind_sampler_states named: the record arm's "
+                       "lookup went to the identity-keyed registry with a content-addressed handle and "
+                       "could never hit (F-4)";
+                EXPECT_EQ(peek.BoundSamplerId, peek.CsoTwinSamplerId)
+                    << "the driver sampler on unit 0 is not the CSO's twin, so it was put there by the "
+                       "pre-handle program pass and not by the record arm (F-4)";
+                EXPECT_EQ(peek.IdentityTwinSamplerId, 0u)
+                    << "an identity-keyed twin was minted for the sampler object on the handle arm: the "
+                       "pre-handle pass is still the one doing the binding";
+            }
+
+            glBindSampler(0, 0);
+            glBindTexture(GL_TEXTURE_2D, 0);
+            glUseProgram(0);
+            DestroyColorFbo(target);
+            glDeleteSamplers(1, &sampler);
+            glDeleteTextures(1, &red);
+            glDeleteProgram(program);
+            EXPECT_EQ(FirstGLError(), 0u) << GLErrorName(FirstGLError());
+        }
+
+    } // namespace
+} // namespace MGITest

MobileGL/MG_IntegrationTest/Scenarios/TextureParamsWithoutASamplerViewScenario.cpp

@@ -0,0 +1,775 @@
+// MobileGL - MobileGL/MG_IntegrationTest/Scenarios/TextureParamsWithoutASamplerViewScenario.cpp
+// Copyright (c) 2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+//
+// Scenario - A TEXTURE'S PARAMETERS TAKE EFFECT EVEN WHEN IT HAS NO SAMPLER VIEW (gate G9), the
+// one scenario ROADMAP.md:20 names by hand and requires to be RED before P4a lands.
+//
+// THE DESIGN STATEMENT IT TESTS, ARCHITECTURE.md:100 (D10), verbatim: "SetTextureParams 按资源寻址、
+// 与 sampler view 分开（D10）：只作 FBO attachment / image 单元 / glCopyImageSubData 端点的纹理没有
+// sampler view，但 Espryt 对 attachment 也同步纹理参数，且 RequireImageBindableStorage 需要在前端参数
+// 版本不动时强制重同步." A texture that is only an attachment, only an image-unit binding or only a
+// copy endpoint has NO sampler view at all - so a design that carried texture parameters on the
+// view would silently drop them for exactly those textures. P4a addresses set_texture_params by
+// RESOURCE, independently of any binding, which is what makes the record exist for every texture
+// the moment its parameters move.
+//
+// THE FOUR CASES, and BRIEF-P4A.md D-E3 is where their expected verdicts come from:
+//
+//   AnAttachmentOnlyTexturesSwizzleReachesTheDriver                        green today, green after
+//   AReadAttachmentOnlyTexturesDepthStencilModeReachesTheDriver            D-E3 says RED today
+//   AnImageUnitOnlyTexturesSwizzleSurvivesARequireImageBindableStorageRemint green today, green after
+//   ACopyImageEndpointOnlyTexturesParamsReachTheDriver                     green today, green after
+//
+// [MEASURED, AND IT DOES NOT MATCH D-E3] All four are GREEN on the P4a contract commit (08192d72),
+// on llvmpipe, in the push build. The second one is green FOR A REASON THAT IS ITSELF THE FINDING,
+// and it is written here rather than in a review comment because the next person to try to make it
+// red needs to know why they cannot:
+//
+//   A texture parameter's only public-GL observable is a SAMPLE - nothing about an attachment, an
+//   image binding or a copy endpoint reads a swizzle or an aspect mode - and a sample puts the
+//   texture on SyncNeccessaryTextures' UNIT list. That walk calls SyncTextureParamsToBackend for
+//   every entry whose IsDrawSyncClean is false (DirectGLES.cpp:1896-1898), and IsDrawSyncClean is
+//   false whenever the frontend's parameter version has moved since the last sync
+//   (Managers.h:1399-1416, `m_syncedTextureParamsVersion != paramsVersion`). So the very act of
+//   observing the parameter repairs the state the observation was meant to catch: the gap between
+//   "the parameter moved on a read-attachment-only texture" and "the driver was told" is REAL, and
+//   it is closed by the next sampler binding, which is also the only thing that can see it.
+//
+// What that means for the gate, stated plainly so nobody reads a green here as evidence of
+// anything it is not:
+//
+//   * the four cases are a REGRESSION NET around D10, not the evidence for the change. They pin
+//     the design statement: a texture's parameters take effect however the texture is reached, and
+//     in particular they would go RED if any of the four reachability paths were ever made to
+//     depend on the texture having a sampler VIEW - which is exactly the coupling P4a's
+//     resource-addressed set_texture_params removes and the thing a later phase could reintroduce;
+//   * the "落地前必须红" artefact ROADMAP.md:20 asks for is NOT produced by the public-GL half
+//     of this file, and no public-GL integration scenario on a monolith tree can produce it.
+//     Producing it needs an observation of the DRIVER's texture object taken while the texture is
+//     still read-attachment-only. ID-19 rules that G9 is therefore a WHITE-BOX assertion, and this
+//     file now carries the SCENARIO half of it (the unit half is package D's,
+//     MG_Test/SanityTest.cpp's DirectGLESTextureSync.AnAttachmentOnlyTexturesParametersReachThe
+//     DriverWithNoSamplerView).
+//
+// THE WHITE-BOX HALF, and what it adds to the four cases below. Each case, at the point where its
+// texture is reachable ONLY its own way and BEFORE the observing sample, takes three readings
+// through MG_IntegrationTest/Harness/PipeApplyPeek.h and asserts all three:
+//
+//   (a) the APPLIER holds a set_texture_params record for this texture, at a non-zero ParamsSerial,
+//       carrying the field the case moved;
+//   (b) ESPRYT's applied value for the same texture - read back from the DRIVER, through the twin's
+//       own ES name - is that value ALREADY, not after the first sampler view;
+//   (c) Espryt holds NO SAMPLER VIEW for this texture yet, which is what turns (b) from "applied"
+//       into "applied WITHOUT one" and is the whole claim D10 makes.
+//
+// (c) is the assertion the public-GL half structurally cannot make: making it there would create
+// the view. (b) is the half that goes red on a backend that DEFERS - a tree where the parameter
+// push is gated on a sampler view existing is green on all four public-GL cases forever, because
+// the sample that observes the parameter is also what mints the view and repairs the state.
+//
+// WHAT THE THREE READINGS DO **NOT** COVER, so the next reader does not over-trust them
+// (esprytobj re-review N-9, carried here by request). D's unit probe drives
+// SyncTextureParamsToBackend directly, so the only deferral shape IT can see is one INSIDE that
+// function. These three run through the real per-frame paths and therefore also see a deferral
+// introduced ABOVE it - in SyncNeccessaryTextures, in the attachment walk, or in E's per-unit walk.
+// Between them the two halves cover both, and neither covers both alone.
+//
+// A READING THAT CANNOT BE TAKEN IS DECLINED BY NAME AND THE CASE CONTINUES - it is not a
+// GTEST_SKIP, and that is a deliberate departure from the shape the review sketched. These four
+// cases are dual-purpose: they are also the END-TO-END regression net around D10, and that net is
+// the ONLY thing measuring D10 on exactly the arms where the peek cannot look (the pull build,
+// which has no applier at all; the 0x1ff and 0 lanes, where the texture family is switched off;
+// Magma, which has no Espryt twin). Skipping the case there would delete the one verdict those
+// lanes carry in order to report the absence of a second one. The decline is printed, recorded as
+// a test property and named, so a lane that silently stopped taking the reading is visible in the
+// log rather than in a count.
+//
+// WHY THE SECOND ONE IS THE RED, mechanically (scout-espryt-framebuffer.md 2.6, re-opened at the
+// base ref). Today a texture's parameters ride on the UNIT BINDING and on the DRAW attachment set:
+//
+//   bound to a sampler unit <= the high-water mark  SyncNeccessaryTextures' unit list   -> synced
+//   attachment of the DRAW framebuffer              SyncNeccessaryTextures' FBO list    -> synced
+//   attachment of the READ framebuffer ONLY         SyncCurrentFBO -> SyncToBackend ->
+//                                                   SyncAttachmentObject, which calls
+//                                                   SyncMipmapsToBackend at Managers.cpp:7161
+//                                                   and NOTHING ELSE                    -> NOT synced
+//   bound to an image unit                          SyncImageTextureBinding ->
+//                                                   SyncTextureObjectToBackend, and
+//                                                   RequireImageBindableStorage additionally
+//                                                   forces m_forceTextureParamsResync    -> synced
+//   a glCopyImageSubData endpoint                   MakeGLESCopyImageEndpoint ->
+//                                                   SyncTextureObjectToBackend           -> synced
+//
+// SyncNeccessaryTextures' attachment list reads GetFramebufferBindingSlotChecked(Draw) only
+// (DirectGLES.cpp:1944), so a texture that is exclusively a READ attachment gets its STORAGE synced
+// and its PARAMETERS never. P4a closes that gap deliberately (D-E3): the record is addressed by
+// resource, and Espryt's SyncAttachmentObject applies parameters for ANY attachment, draw or read.
+// It is a behaviour change and it is the deliverable, not a drive-by dev fix (ROADMAP.md:98).
+//
+// HOW EACH CASE OBSERVES "REACHED THE DRIVER", and why the observation is always a LATER SAMPLE.
+// A texture parameter is by definition a sampling parameter: nothing about an attachment, an image
+// binding or a copy endpoint reads a swizzle or a depth/stencil aspect mode, so the only thing that
+// can see one is a sample. Each case therefore does the same three things -
+//
+//   1. put the texture through ONE of the five reachability paths above, and only that one,
+//   2. move a parameter while it is reachable ONLY that way (through the DSA entry points
+//      glTextureParameteri / glTextureSubImage2D, so no step of the setup ever binds the texture to
+//      a sampler unit - a bind would put it on the unit list and answer the question by accident),
+//   3. sample it once, at the end, and read the colour back.
+//
+// - and the difference between them is step 1 alone. A case that is red says: the parameter set
+// while the texture was reachable only that way did not survive to the sample.
+//
+// DIRECTGLES ONLY. The gap is Espryt's - it is a statement about SyncAttachmentObject and
+// SyncNeccessaryTextures - and P4a does not touch MG_Backend/DirectVulkan (D-Q). Magma answers the
+// same GL question through an entirely different path, so a red or a green there would be evidence
+// about P7's work rather than about this gate; the cases SKIP on any other backend, naming that.
+
+#include <cstdint>
+#include <cstdlib>
+#include <iostream>
+#include <string>
+#include <vector>
+
+#include "../Harness/HeadlessGL.h"
+#include "../Harness/PipeApplyPeek.h"
+#include "../Harness/ScenarioFixture.h"
+
+#ifdef GLAPI
+#undef GLAPI
+#endif
+#define GL_GLEXT_PROTOTYPES
+#include <GL/gl.h>
+#include <GL/glcorearb.h>
+#undef GL_GLEXT_PROTOTYPES
+
+namespace MGITest {
+    namespace {
+
+        constexpr int kInset = 2;
+        constexpr int kTextureSize = 4;
+
+        constexpr const char* kQuadVS = R"(#version 330 core
+in vec2 aPos;
+out vec2 vUv;
+void main() {
+    vUv = aPos * 0.5 + 0.5;
+    gl_Position = vec4(aPos, 0.0, 1.0);
+}
+)";
+
+        // Samples texel (0,0) with an explicit fetch: no filtering, no derivatives, no wrap - so
+        // the colour that comes back is the texel as the driver's swizzle presents it and nothing
+        // else can move it.
+        constexpr const char* kFetchFS = R"(#version 330 core
+uniform sampler2D uTex;
+out vec4 oColor;
+void main() { oColor = texelFetch(uTex, ivec2(0, 0), 0); }
+)";
+
+        // The stencil aspect of a packed depth/stencil texture is an UNSIGNED INTEGER texture, so
+        // it needs a usampler2D. The case that uses it turns "the stencil value is what was
+        // cleared" into a colour, because a colour is the only thing this harness can read back.
+        constexpr const char* kStencilFetchFS = R"(#version 330 core
+uniform usampler2D uTex;
+uniform uint uExpected;
+out vec4 oColor;
+void main() {
+    uint value = texelFetch(uTex, ivec2(0, 0), 0).r;
+    oColor = (value == uExpected) ? vec4(0.0, 1.0, 0.0, 1.0) : vec4(1.0, 0.0, 0.0, 1.0);
+}
+)";
+
+        struct Vertex {
+            float x, y;
+        };
+
+        class TextureParamsWithoutASamplerViewScenario : public ScenarioTest {
+        protected:
+            void SetUp() override {
+                ScenarioTest::SetUp();
+                if (!Ready()) return;
+                if (Gl().BackendName() != "DirectGLES") {
+                    GTEST_SKIP() << "DirectGLES only: this scenario is about Espryt's own reachability "
+                                    "table - SyncNeccessaryTextures' attachment list walks the DRAW "
+                                    "slot only (DirectGLES.cpp:1944) and SyncAttachmentObject syncs "
+                                    "storage and not parameters (Managers.cpp:7161). "
+                                 << Gl().BackendName()
+                                 << " answers the same GL question through a different path, so a "
+                                    "verdict here would be evidence about that backend rather than "
+                                    "about this gate (P4a touches no DirectVulkan source but "
+                                    "MagmaPipeArms.h, D-Q).";
+                }
+                std::string error;
+                m_fetchProgram = CompileProgram(kQuadVS, kFetchFS, &error);
+                ASSERT_NE(m_fetchProgram, 0u) << error;
+
+                static const Vertex quad[6] = {{-1.0f, -1.0f}, {1.0f, -1.0f}, {1.0f, 1.0f},
+                                               {-1.0f, -1.0f}, {1.0f, 1.0f},  {-1.0f, 1.0f}};
+                glGenBuffers(1, &m_quadBuffer);
+                glBindBuffer(GL_ARRAY_BUFFER, m_quadBuffer);
+                glBufferData(GL_ARRAY_BUFFER, sizeof(quad), quad, GL_STATIC_DRAW);
+                glGenVertexArrays(1, &m_vao);
+                glBindVertexArray(m_vao);
+                glEnableVertexAttribArray(0);
+                glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), nullptr);
+                glBindVertexArray(0);
+                ASSERT_EQ(FirstGLError(), GLenum(GL_NO_ERROR)) << "the scene setup left a GL error behind";
+            }
+
+            void TearDown() override {
+                if (!Ready() || IsSkipped()) return;
+                glUseProgram(0);
+                glBindVertexArray(0);
+                if (m_vao != 0) glDeleteVertexArrays(1, &m_vao);
+                if (m_quadBuffer != 0) glDeleteBuffers(1, &m_quadBuffer);
+                if (m_fetchProgram != 0) glDeleteProgram(m_fetchProgram);
+            }
+
+            // Direct State Access is how every setup step below touches a texture, and it is the
+            // whole reason the cases can claim "this texture never had a sampler view": the classic
+            // entry points (glTexImage2D, glTexParameteri) all require the texture to be BOUND to a
+            // unit first, and a bind is exactly what puts it on SyncNeccessaryTextures' unit list.
+            // A case that used them would sync the parameters through the path it is trying to
+            // exclude and would be green for the wrong reason, on every tree, forever.
+            bool DirectStateAccessIsAvailable() {
+                GLuint probe = 0;
+                glCreateTextures(GL_TEXTURE_2D, 1, &probe);
+                const bool ok = FirstGLError() == GLenum(GL_NO_ERROR) && probe != 0;
+                if (probe != 0) glDeleteTextures(1, &probe);
+                return ok;
+            }
+
+            void SkipWithoutDirectStateAccess() {
+                if (!DirectStateAccessIsAvailable()) {
+                    GTEST_SKIP() << "glCreateTextures is not usable here, and every case in this file "
+                                    "needs the DSA entry points: the classic ones bind the texture to "
+                                    "a unit, which is the reachability path these cases exist to "
+                                    "exclude. A case that fell back to them would be green for the "
+                                    "wrong reason rather than measuring anything.";
+                }
+            }
+
+            // A 4x4 RGBA8 texture, one solid colour, created and filled WITHOUT EVER BINDING IT.
+            GLuint MakeSolidTextureWithoutBinding(std::uint8_t r, std::uint8_t g, std::uint8_t b) {
+                std::vector<std::uint8_t> texels(kTextureSize * kTextureSize * 4);
+                for (std::size_t i = 0; i < texels.size(); i += 4) {
+                    texels[i] = r;
+                    texels[i + 1] = g;
+                    texels[i + 2] = b;
+                    texels[i + 3] = 255;
+                }
+                GLuint texture = 0;
+                glCreateTextures(GL_TEXTURE_2D, 1, &texture);
+                glTextureStorage2D(texture, 1, GL_RGBA8, kTextureSize, kTextureSize);
+                glTextureSubImage2D(texture, 0, 0, 0, kTextureSize, kTextureSize, GL_RGBA,
+                                    GL_UNSIGNED_BYTE, texels.data());
+                glTextureParameteri(texture, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+                glTextureParameteri(texture, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+                return texture;
+            }
+
+            // THE OBSERVATION, shared by every case: bind the texture to a unit for the first time
+            // in its life and read one texel back through the default framebuffer.
+            Image SampleAndRead(GLuint program, GLuint texture) {
+                BindDefaultFramebuffer();
+                glViewport(0, 0, Gl().Width(), Gl().Height());
+                ClearTo(0.0f, 0.0f, 0.0f, 1.0f);
+                glUseProgram(program);
+                glUniform1i(glGetUniformLocation(program, "uTex"), 0);
+                glActiveTexture(GL_TEXTURE0);
+                glBindTexture(GL_TEXTURE_2D, texture);
+                glBindVertexArray(m_vao);
+                glDrawArrays(GL_TRIANGLES, 0, 6);
+                const Image image = ReadPixels(Gl().Width(), Gl().Height());
+                Gl().EndFrame();
+                glBindTexture(GL_TEXTURE_2D, 0);
+                return image;
+            }
+
+            ::testing::AssertionResult WholeViewportIs(const Image& image, const char* expected,
+                                                       const std::string& when) {
+                return RegionIsMostly(image, kInset, image.Width() - kInset, kInset,
+                                      image.Height() - kInset, expected, 0.0, when);
+            }
+
+            // R -> ZERO and G -> ONE, so a RED texel samples as GREEN if and only if the swizzle
+            // reached the driver, and as RED if it did not. Two colours the harness can name, from
+            // one parameter change, with no third outcome that could be mistaken for either.
+            void SwizzleRedIntoGreen(GLuint texture) {
+                glTextureParameteri(texture, GL_TEXTURE_SWIZZLE_R, GL_ZERO);
+                glTextureParameteri(texture, GL_TEXTURE_SWIZZLE_G, GL_ONE);
+                glTextureParameteri(texture, GL_TEXTURE_SWIZZLE_B, GL_ZERO);
+            }
+
+            // Which of the two parameters a case moved, and therefore which one the white-box
+            // reading has to find on both sides of the seam. Two, because they are the two the
+            // four cases use and because a peek that reported "some parameter" would be green for
+            // a backend that applied the wrong one.
+            enum class MovedParameter { Swizzle, DepthStencilMode };
+
+            // ------------------------------------------------------------------------------
+            // G9's WHITE-BOX READING (ID-19). Called by every case at the point where its
+            // texture is reachable only its own way and BEFORE the observing sample - which is
+            // the whole of the design, because the sample repairs what it observes.
+            //
+            // `expectedSwizzle` is the four GL enums the case set (or left at their defaults);
+            // `expectedDepthStencilMode` is GL_DEPTH_COMPONENT or GL_STENCIL_INDEX. Both are
+            // always passed and `moved` says which one is the case's subject, so a reader of a
+            // failure can see the untouched half beside the moved one.
+            void TakeTheWhiteBoxReadingBeforeAnySample(GLuint texture, GLenum target,
+                                                       MovedParameter moved,
+                                                       const GLint expectedSwizzle[4],
+                                                       GLint expectedDepthStencilMode,
+                                                       const char* whatMadeItReachable) {
+                const char* const movedName =
+                    moved == MovedParameter::Swizzle ? "GL_TEXTURE_SWIZZLE_*"
+                                                     : "GL_DEPTH_STENCIL_TEXTURE_MODE";
+
+                PipeTextureParamsRecordPeek record{};
+                if (!PeekPipeTextureParamsRecord(static_cast<unsigned>(texture), &record)) {
+                    DeclineTheWhiteBoxReading(
+                        "no set_texture_params record for this texture in the applier. Either "
+                        "there is no applier here (a PULL build: MGPipeApplierState is "
+                        "#if MOBILEGL_PIPE_PUSH), or this lane's MOBILEGL_PIPE_PUSH leaves "
+                        "kMGPipeSubsystemTextureResources (bit 10) clear, or no backend "
+                        "registered MGPipeResourceOps so the client never emitted (c0f). The "
+                        "end-to-end half of this case below is unaffected and still decides it.");
+                    return;
+                }
+
+                // From here the reading WAS taken, so everything is a hard assertion: a record
+                // that exists and does not carry the parameter is exactly the finding.
+                EXPECT_NE(record.ParamsSerial, 0u)
+                    << "the applier holds a resource record for texture " << texture
+                    << " at handle {" << record.Slot << ", " << record.Gen
+                    << "} but its ParamsSerial is 0, i.e. NO set_texture_params has ever been "
+                       "applied to it - and this case moved " << movedName << " while the texture "
+                       "was " << whatMadeItReachable
+                    << ". A parameter change on a texture with no sampler view has to produce a "
+                       "record addressed BY RESOURCE (D10, D-E1); a zero here means the client "
+                       "never emitted one, which is the coupling P4a exists to remove reappearing "
+                       "on the emitter's side of the seam.";
+
+                if (moved == MovedParameter::Swizzle) {
+                    for (int channel = 0; channel < 4; ++channel) {
+                        EXPECT_EQ(record.Swizzle[channel], static_cast<int>(expectedSwizzle[channel]))
+                            << "the applier's set_texture_params record for texture " << texture
+                            << " carries the wrong swizzle in channel " << channel
+                            << " (record 0x" << std::hex << record.Swizzle[channel] << ", expected 0x"
+                            << expectedSwizzle[channel] << std::dec
+                            << "). The record is what Espryt reads, so a wrong value here is a "
+                               "wrong value everywhere downstream of it.";
+                    }
+                } else {
+                    EXPECT_EQ(record.DepthStencilMode, static_cast<int>(expectedDepthStencilMode))
+                        << "the applier's set_texture_params record for texture " << texture
+                        << " carries GL_DEPTH_STENCIL_TEXTURE_MODE 0x" << std::hex
+                        << record.DepthStencilMode << ", expected 0x" << expectedDepthStencilMode
+                        << std::dec << ".";
+                }
+
+                // (c) - and it is checked BEFORE (b) is read, because (b) reads the driver and a
+                // reader of a failure needs to know the view question was answered on the state
+                // this case built rather than on anything the peek did.
+                bool hasSamplerView = true;
+                if (!PeekEsprytHasSamplerViewForTexture(static_cast<unsigned>(texture),
+                                                        &hasSamplerView)) {
+                    DeclineTheWhiteBoxReading(
+                        "Espryt holds no twin for this texture, so neither the sampler-view "
+                        "question nor the applied-value one can be asked here. On a backend other "
+                        "than DirectGLES that is the designed state (P4a touches no DirectVulkan "
+                        "source but MagmaPipeArms.h, D-Q).");
+                    return;
+                }
+                EXPECT_FALSE(hasSamplerView)
+                    << "Espryt already holds a SAMPLER VIEW for texture " << texture
+                    << ", which was " << whatMadeItReachable
+                    << " and has never been bound to a sampler unit in this case. The whole claim "
+                       "of D10 is that a texture reached this way has no view, so if one exists "
+                       "the reading below cannot separate 'applied by resource' from 'applied "
+                       "through the view' and this case has stopped measuring G9.";
+
+                EsprytAppliedTextureParamsPeek applied{};
+                if (!PeekEsprytAppliedTextureParams(static_cast<unsigned>(texture),
+                                                    static_cast<unsigned>(target), &applied)) {
+                    DeclineTheWhiteBoxReading(
+                        "Espryt's applied value could not be read back from the driver (no twin, "
+                        "no ES name yet, or a target this peek has no binding query for).");
+                    return;
+                }
+
+                std::cout << "[ TextureParamsWithoutASamplerView ] white-box: texture " << texture
+                          << " -> applier handle {" << record.Slot << ", " << record.Gen
+                          << "} paramsSerial " << record.ParamsSerial << ", Espryt ES name "
+                          << applied.BackendTextureId << ", sampler view: none, " << movedName
+                          << " applied before any sample" << std::endl;
+
+                if (moved == MovedParameter::Swizzle) {
+                    for (int channel = 0; channel < 4; ++channel) {
+                        EXPECT_EQ(applied.Swizzle[channel], static_cast<int>(expectedSwizzle[channel]))
+                            << "ESPRYT HAS NOT APPLIED THE SWIZZLE YET. Channel " << channel
+                            << " of the driver texture (ES name " << applied.BackendTextureId
+                            << ") reads 0x" << std::hex << applied.Swizzle[channel] << ", the "
+                            << "application set 0x" << expectedSwizzle[channel] << std::dec
+                            << ", and the applier's record already carries the right value - so "
+                               "the record reached the server and the server has not pushed it. "
+                               "The texture was " << whatMadeItReachable
+                            << " and has NO sampler view (asserted above), which makes this "
+                               "exactly the deferred-to-first-view shape G9 exists to catch: the "
+                               "sample at the end of this case would repair it, and the "
+                               "end-to-end assertion below would then pass on a driver that was "
+                               "told late. That is the half no public-GL case can see.";
+                    }
+                } else {
+                    if (!applied.DepthStencilModeIsReadable) {
+                        DeclineTheWhiteBoxReading(
+                            "this driver would not answer glGetTexParameteriv("
+                            "GL_DEPTH_STENCIL_TEXTURE_MODE), so the applied aspect mode cannot be "
+                            "read back. The record half above was still asserted.");
+                        return;
+                    }
+                    EXPECT_EQ(applied.DepthStencilMode, static_cast<int>(expectedDepthStencilMode))
+                        << "ESPRYT HAS NOT APPLIED THE DEPTH/STENCIL ASPECT MODE YET. The driver "
+                           "texture (ES name " << applied.BackendTextureId << ") reads 0x"
+                        << std::hex << applied.DepthStencilMode << ", the application set 0x"
+                        << expectedDepthStencilMode << std::dec
+                        << ", and the applier's record already carries the right value. The "
+                           "texture was " << whatMadeItReachable
+                        << " and has no sampler view, so this is D-E3's gap measured directly "
+                           "rather than through a sample that would repair it: a driver left at "
+                           "GL_DEPTH_COMPONENT samples the DEPTH bits where the application asked "
+                           "for stencil.";
+                }
+            }
+
+            // Printed, recorded and named, never silent - a lane that stopped taking the reading
+            // must be visible in the log. See this file's header for why it is not a GTEST_SKIP.
+            void DeclineTheWhiteBoxReading(const std::string& why) {
+                std::cout << "[ TextureParamsWithoutASamplerView ] white-box reading DECLINED: "
+                          << why << std::endl;
+                RecordProperty("g9_white_box", "declined");
+                RecordProperty("g9_white_box_reason", why.c_str());
+            }
+
+            GLuint m_fetchProgram = 0;
+            GLuint m_vao = 0;
+            GLuint m_quadBuffer = 0;
+        };
+
+        // The swizzle SwizzleRedIntoGreen leaves behind, as GL enums: R -> ZERO, G -> ONE,
+        // B -> ZERO and A untouched at its GL default. Written once here because both the
+        // applier record and the driver read-back are compared against it.
+        constexpr GLint kRedIntoGreenSwizzle[4] = {GL_ZERO, GL_ONE, GL_ZERO, GL_ALPHA};
+        // A texture whose aspect mode was never touched, i.e. the GL initial value - which is
+        // also what a zeroed MGPTextureParams::DepthStencilMode decodes to (MGPipeTypes.h).
+        constexpr GLint kUntouchedDepthStencilMode = GL_DEPTH_COMPONENT;
+        // ...and the identity swizzle, for the case whose subject is the aspect mode: the moved
+        // half is asserted, and the untouched half is carried so a failure prints both.
+        constexpr GLint kUntouchedSwizzle[4] = {GL_RED, GL_GREEN, GL_BLUE, GL_ALPHA};
+
+        // ------------------------------------------------------------------------------------
+        // 1. DRAW ATTACHMENT ONLY. Green today (SyncNeccessaryTextures' FBO list walks the draw
+        //    slot and calls SyncTextureObjectToBackend, which syncs parameters) and green after.
+        //    It is the regression net for the half of D-E3 that already works: P4a moves the
+        //    parameter sync from the sync list onto the record, and this case is what says the
+        //    move did not lose the case that used to be covered.
+        // ------------------------------------------------------------------------------------
+        TEST_F(TextureParamsWithoutASamplerViewScenario, AnAttachmentOnlyTexturesSwizzleReachesTheDriver) {
+            if (!Ready()) return;
+            SkipWithoutDirectStateAccess();
+            if (IsSkipped()) return;
+
+            const GLuint texture = MakeSolidTextureWithoutBinding(255, 0, 0);
+            GLuint fbo = 0;
+            glGenFramebuffers(1, &fbo);
+            glBindFramebuffer(GL_DRAW_FRAMEBUFFER, fbo);
+            glFramebufferTexture2D(GL_DRAW_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, texture, 0);
+            ASSERT_EQ(glCheckFramebufferStatus(GL_DRAW_FRAMEBUFFER), GLenum(GL_FRAMEBUFFER_COMPLETE));
+
+            // The parameter moves while the texture is reachable ONLY as a draw attachment...
+            SwizzleRedIntoGreen(texture);
+            // ...and a frame runs with it bound that way, so whatever the draw path syncs, syncs.
+            glViewport(0, 0, kTextureSize, kTextureSize);
+            ClearTo(1.0f, 0.0f, 0.0f, 1.0f);
+            BindDefaultFramebuffer();
+            Gl().EndFrame();
+            ASSERT_EQ(FirstGLError(), GLenum(GL_NO_ERROR)) << "the draw-attachment frame left a GL error";
+
+            glBindFramebuffer(GL_FRAMEBUFFER, 0);
+            glDeleteFramebuffers(1, &fbo);
+
+            // G9's white-box reading, taken here: the texture has been a draw attachment and
+            // nothing else, and the sample below has not happened yet.
+            TakeTheWhiteBoxReadingBeforeAnySample(texture, GL_TEXTURE_2D, MovedParameter::Swizzle,
+                                                  kRedIntoGreenSwizzle, kUntouchedDepthStencilMode,
+                                                  "an attachment of the DRAW framebuffer and "
+                                                  "nothing else");
+
+            const Image image = SampleAndRead(m_fetchProgram, texture);
+            EXPECT_TRUE(WholeViewportIs(image, "green",
+                                        "a texture that was only ever a DRAW attachment, sampled "
+                                        "after its swizzle moved"))
+                << "the swizzle set while this texture was reachable only as a draw-framebuffer "
+                   "attachment did not reach the driver: a red texel with R->ZERO, G->ONE must "
+                   "sample as green.";
+
+            GLuint cleanup = texture;
+            glDeleteTextures(1, &cleanup);
+        }
+
+        // ------------------------------------------------------------------------------------
+        // 2. READ ATTACHMENT ONLY - THE MANDATORY RED (ROADMAP.md:20, D-E3, G9).
+        //
+        //    The parameter is GL_DEPTH_STENCIL_TEXTURE_MODE and the texture is a packed
+        //    depth/stencil one, because that is the parameter whose absence is not a mis-filtered
+        //    picture but the WRONG ASPECT: a driver left at the GL default samples the depth bits
+        //    where the application asked for stencil, and the value that comes back is not the
+        //    stencil that was written. RecreateBackendTexture's own comment says exactly this -
+        //    "the mode makes it visible because falling back to the default silently samples the
+        //    wrong aspect rather than merely mis-filtering" (Managers.cpp:4826-4833).
+        //
+        //    The framebuffer is bound to GL_READ_FRAMEBUFFER and the DRAW target is left on the
+        //    default framebuffer for the whole window, which is the ONE thing that separates this
+        //    case from the one above.
+        // ------------------------------------------------------------------------------------
+        TEST_F(TextureParamsWithoutASamplerViewScenario,
+               AReadAttachmentOnlyTexturesDepthStencilModeReachesTheDriver) {
+            if (!Ready()) return;
+            SkipWithoutDirectStateAccess();
+            if (IsSkipped()) return;
+
+            std::string error;
+            const GLuint stencilProgram = CompileProgram(kQuadVS, kStencilFetchFS, &error);
+            ASSERT_NE(stencilProgram, 0u) << error;
+
+            GLuint texture = 0;
+            glCreateTextures(GL_TEXTURE_2D, 1, &texture);
+            glTextureStorage2D(texture, 1, GL_DEPTH24_STENCIL8, kTextureSize, kTextureSize);
+            glTextureParameteri(texture, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+            glTextureParameteri(texture, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+            if (FirstGLError() != GLenum(GL_NO_ERROR)) {
+                glDeleteTextures(1, &texture);
+                glDeleteProgram(stencilProgram);
+                GTEST_SKIP() << "this driver would not create an immutable DEPTH24_STENCIL8 texture, "
+                                "so there is no packed depth/stencil aspect here to sample and the "
+                                "case cannot answer";
+            }
+
+            // Write a stencil value through the texture AS A DRAW ATTACHMENT once, so that there is
+            // something in the stencil aspect to read. This is setup, not the window: the window
+            // below never makes it a draw attachment again.
+            GLuint fbo = 0;
+            glGenFramebuffers(1, &fbo);
+            glBindFramebuffer(GL_FRAMEBUFFER, fbo);
+            glFramebufferTexture2D(GL_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_TEXTURE_2D, texture, 0);
+            glDrawBuffer(GL_NONE);
+            glReadBuffer(GL_NONE);
+            if (glCheckFramebufferStatus(GL_FRAMEBUFFER) != GLenum(GL_FRAMEBUFFER_COMPLETE)) {
+                BindDefaultFramebuffer();
+                glDeleteFramebuffers(1, &fbo);
+                glDeleteTextures(1, &texture);
+                glDeleteProgram(stencilProgram);
+                GTEST_SKIP() << "a depth-stencil-only framebuffer is incomplete on this driver, so "
+                                "the stencil aspect cannot be written and the case cannot answer";
+            }
+            constexpr GLint kStencil = 42;
+            glViewport(0, 0, kTextureSize, kTextureSize);
+            glStencilMask(0xFFu);
+            glClearBufferfi(GL_DEPTH_STENCIL, 0, 0.5f, kStencil);
+            BindDefaultFramebuffer();
+            Gl().EndFrame();
+            ASSERT_EQ(FirstGLError(), GLenum(GL_NO_ERROR)) << "clearing the stencil aspect left a GL error";
+
+            // ---- the window: the texture is reachable ONLY as a READ attachment ----
+            //
+            // The DRAW binding is the default framebuffer throughout, so SyncNeccessaryTextures'
+            // attachment list - which walks the DRAW slot only - never sees this texture, and
+            // SyncCurrentFBO's read path reaches it through SyncAttachmentObject, which syncs
+            // storage and not parameters. That is the gap.
+            glBindFramebuffer(GL_READ_FRAMEBUFFER, fbo);
+            glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
+            glTextureParameteri(texture, GL_DEPTH_STENCIL_TEXTURE_MODE, GL_STENCIL_INDEX);
+            // A frame with the read binding live, and it has to contain a REAL DRAW: SyncCurrentFBO
+            // and the whole sync-list walk run at the validate point, so a frame that only cleared
+            // and swapped would never reach the read-side path this case is about.
+            glViewport(0, 0, Gl().Width(), Gl().Height());
+            ClearTo(0.0f, 0.0f, 0.0f, 1.0f);
+            glUseProgram(m_fetchProgram);
+            glUniform1i(glGetUniformLocation(m_fetchProgram, "uTex"), 0);
+            glActiveTexture(GL_TEXTURE0);
+            glBindTexture(GL_TEXTURE_2D, 0);
+            glBindVertexArray(m_vao);
+            glDrawArrays(GL_TRIANGLES, 0, 6);
+            Gl().EndFrame();
+            glBindFramebuffer(GL_READ_FRAMEBUFFER, 0);
+            ASSERT_EQ(FirstGLError(), GLenum(GL_NO_ERROR)) << "the read-attachment frame left a GL error";
+
+            // G9's white-box reading, and this is the case it matters most for: the aspect
+            // mode was set while the texture was reachable ONLY as a read attachment, and the
+            // observation below is a sample that would repair an unsynced parameter on its way
+            // to reporting it.
+            TakeTheWhiteBoxReadingBeforeAnySample(texture, GL_TEXTURE_2D,
+                                                  MovedParameter::DepthStencilMode,
+                                                  kUntouchedSwizzle, GL_STENCIL_INDEX,
+                                                  "an attachment of the READ framebuffer and "
+                                                  "nothing else");
+
+            // ---- the observation ----
+            BindDefaultFramebuffer();
+            glViewport(0, 0, Gl().Width(), Gl().Height());
+            ClearTo(0.0f, 0.0f, 0.0f, 1.0f);
+            glUseProgram(stencilProgram);
+            glUniform1i(glGetUniformLocation(stencilProgram, "uTex"), 0);
+            glUniform1ui(glGetUniformLocation(stencilProgram, "uExpected"),
+                         static_cast<GLuint>(kStencil));
+            glActiveTexture(GL_TEXTURE0);
+            glBindTexture(GL_TEXTURE_2D, texture);
+            glBindVertexArray(m_vao);
+            glDrawArrays(GL_TRIANGLES, 0, 6);
+            const Image image = ReadPixels(Gl().Width(), Gl().Height());
+            Gl().EndFrame();
+            glBindTexture(GL_TEXTURE_2D, 0);
+
+            const GLenum sampleError = FirstGLError();
+            std::cout << "[ TextureParamsWithoutASamplerView ] read-attachment-only "
+                         "GL_DEPTH_STENCIL_TEXTURE_MODE=GL_STENCIL_INDEX, expecting stencil "
+                      << kStencil << "; sample GL error 0x" << std::hex << sampleError << std::dec
+                      << std::endl;
+
+            EXPECT_TRUE(WholeViewportIs(image, "green",
+                                        "a texture that was only ever a READ attachment, sampled "
+                                        "through its stencil aspect"))
+                << "GL_DEPTH_STENCIL_TEXTURE_MODE = GL_STENCIL_INDEX was set while this texture was "
+                   "reachable ONLY as an attachment of the READ framebuffer, and the sample did not "
+                   "come back as the stencil value that was cleared into it. The parameter did not "
+                   "reach the driver, and - because the sample itself would have repaired an "
+                   "unsynced parameter (see this file's header: the unit sync list calls "
+                   "SyncTextureParamsToBackend whenever the params version moved) - a red here means "
+                   "something stronger than the D-E3 gap: a reachability path that does not sync "
+                   "parameters AT ALL, i.e. the sampler-view coupling ARCHITECTURE.md:100 (D10) "
+                   "exists to remove. Read the case's own stdout line for the GL error the sample "
+                   "raised before assuming an aspect-mode bug.";
+
+            BindDefaultFramebuffer();
+            glDeleteFramebuffers(1, &fbo);
+            glDeleteTextures(1, &texture);
+            glDeleteProgram(stencilProgram);
+        }
+
+        // ------------------------------------------------------------------------------------
+        // 3. IMAGE UNIT ONLY, across a storage RE-MINT. Green today and green after, and the
+        //    reason it is green is the thing P4a must not lose: glBindImageTexture drives
+        //    RequireImageBindableStorage, which re-mints the storage in a possibly WIDENED carrier
+        //    and sets m_forceTextureParamsResync (Managers.cpp:4787) precisely because the
+        //    frontend's parameter version does not move across that transition. A parameter sync
+        //    gated only on the frontend version would leave the driver at its defaults and sample
+        //    the carrier's surplus channels raw.
+        // ------------------------------------------------------------------------------------
+        TEST_F(TextureParamsWithoutASamplerViewScenario,
+               AnImageUnitOnlyTexturesSwizzleSurvivesARequireImageBindableStorageRemint) {
+            if (!Ready()) return;
+            SkipWithoutDirectStateAccess();
+            if (IsSkipped()) return;
+
+            const GLuint texture = MakeSolidTextureWithoutBinding(255, 0, 0);
+
+            // The parameter moves while the texture is reachable only as an image-unit binding...
+            SwizzleRedIntoGreen(texture);
+            glBindImageTexture(0, texture, 0, GL_FALSE, 0, GL_READ_ONLY, GL_RGBA8);
+            const GLenum bindError = FirstGLError();
+            if (bindError != GLenum(GL_NO_ERROR)) {
+                glBindImageTexture(0, 0, 0, GL_FALSE, 0, GL_READ_ONLY, GL_RGBA8);
+                GLuint cleanup = texture;
+                glDeleteTextures(1, &cleanup);
+                GTEST_SKIP() << "glBindImageTexture is not usable here (GL error 0x" << std::hex
+                             << bindError << std::dec
+                             << "), so the RequireImageBindableStorage transition this case is about "
+                                "cannot be reached";
+            }
+            // ...and a frame runs with the image binding live, which is what drives the re-mint.
+            glViewport(0, 0, Gl().Width(), Gl().Height());
+            ClearTo(0.0f, 0.0f, 0.0f, 1.0f);
+            Gl().EndFrame();
+            glBindImageTexture(0, 0, 0, GL_FALSE, 0, GL_READ_ONLY, GL_RGBA8);
+
+            // G9's white-box reading. RGBA8 is a core image format, so no widening carrier is
+            // minted and the driver's swizzle is the application's own - the composition
+            // RecreateBackendTexture applies for a NON-core format would show up here as a
+            // legitimate difference and this case deliberately does not use one.
+            TakeTheWhiteBoxReadingBeforeAnySample(texture, GL_TEXTURE_2D, MovedParameter::Swizzle,
+                                                  kRedIntoGreenSwizzle, kUntouchedDepthStencilMode,
+                                                  "an image-unit binding and nothing else, across "
+                                                  "a RequireImageBindableStorage re-mint");
+
+            const Image image = SampleAndRead(m_fetchProgram, texture);
+            EXPECT_TRUE(WholeViewportIs(image, "green",
+                                        "a texture that was only ever an image-unit binding, sampled "
+                                        "after its swizzle moved and its storage was re-minted"))
+                << "the swizzle did not survive the RequireImageBindableStorage re-mint. The re-mint "
+                   "creates a new driver texture at the ES defaults without moving the frontend's "
+                   "parameter version, so the forced resync (Managers.cpp:4787) is the only thing "
+                   "that puts the application's parameters back.";
+
+            GLuint cleanup = texture;
+            glDeleteTextures(1, &cleanup);
+        }
+
+        // ------------------------------------------------------------------------------------
+        // 4. glCopyImageSubData ENDPOINT ONLY. Green today (MakeGLESCopyImageEndpoint calls
+        //    SyncTextureObjectToBackend, DirectGLES.cpp:7588) and green after. The endpoint is the
+        //    DESTINATION, so the case also proves the copy itself still lands: a swizzled read of
+        //    the copied texel is only meaningful if the texel arrived.
+        // ------------------------------------------------------------------------------------
+        TEST_F(TextureParamsWithoutASamplerViewScenario,
+               ACopyImageEndpointOnlyTexturesParamsReachTheDriver) {
+            if (!Ready()) return;
+            SkipWithoutDirectStateAccess();
+            if (IsSkipped()) return;
+
+            const GLuint source = MakeSolidTextureWithoutBinding(255, 0, 0);
+            const GLuint destination = MakeSolidTextureWithoutBinding(0, 0, 255);
+
+            // The parameter moves while the destination is reachable only as a copy endpoint...
+            SwizzleRedIntoGreen(destination);
+            glCopyImageSubData(source, GL_TEXTURE_2D, 0, 0, 0, 0, destination, GL_TEXTURE_2D, 0, 0, 0,
+                               0, kTextureSize, kTextureSize, 1);
+            const GLenum copyError = FirstGLError();
+            if (copyError != GLenum(GL_NO_ERROR)) {
+                GLuint cleanup[2] = {source, destination};
+                glDeleteTextures(2, cleanup);
+                GTEST_SKIP() << "glCopyImageSubData is not usable here (GL error 0x" << std::hex
+                             << copyError << std::dec << "), so there is no copy endpoint to be";
+            }
+            Gl().EndFrame();
+
+            // G9's white-box reading, on the DESTINATION - the endpoint whose parameters moved.
+            TakeTheWhiteBoxReadingBeforeAnySample(destination, GL_TEXTURE_2D,
+                                                  MovedParameter::Swizzle, kRedIntoGreenSwizzle,
+                                                  kUntouchedDepthStencilMode,
+                                                  "a glCopyImageSubData destination and nothing "
+                                                  "else");
+
+            // ...and the destination now holds the source's RED texel, which the swizzle must turn
+            // into GREEN when it is finally sampled.
+            const Image image = SampleAndRead(m_fetchProgram, destination);
+            EXPECT_TRUE(WholeViewportIs(image, "green",
+                                        "a texture that was only ever a glCopyImageSubData endpoint, "
+                                        "sampled after its swizzle moved"))
+                << "the three readings are distinct and each names its own cause: GREEN is the pass "
+                   "(the swizzle reached the driver); RED means the copy landed and the swizzle did "
+                   "not; BLUE means neither happened, i.e. the destination is still its own original "
+                   "texel and glCopyImageSubData wrote nothing. The swizzle is what turns any texel "
+                   "into (0,1,0), so the colour separates the two failures rather than merging them.";
+
+            GLuint cleanup[2] = {source, destination};
+            glDeleteTextures(2, cleanup);
+        }
+
+    } // namespace
+} // namespace MGITest

MobileGL/MG_IntegrationTest/Scenarios/TextureUploadShapeScenario.cpp

@@ -0,0 +1,396 @@
+// MobileGL - MobileGL/MG_IntegrationTest/Scenarios/TextureUploadShapeScenario.cpp
+// Copyright (c) 2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+//
+// Scenario - THE TEXTURE UPLOAD SHAPE, RECORDED (BRIEF-P4A.md D-D4). NOT A GATE IN P4a.
+//
+// WHAT IT IS FOR. SSIM is completely blind to the difference between "one union box" and "N
+// separate rects", and that difference is the Mali upload cliff: Mali prices an upload by the
+// number of JOBS, and ~100 one-rect sprite jobs against one union box measured +6 ms/frame
+// (ARCHITECTURE.md:249-251). Every P4a gate can be green while the emission shape has silently
+// inverted, so the shape needs a number - and there are TWO numbers, deliberately:
+//
+//   tex[emit= box= rect= jobs=]   the SERVER's count, Espryt's own, which has existed since P2
+//   emit[ctu=]                    the CLIENT's count of the same records (CallClass::
+//                                 ClientTextureUploadEmissions, minted by the P4a contract commit)
+//
+// The two agreeing is the whole reason both are printed (D-L). An emission-shape divergence between
+// the client that decides the rect model and the server that pays the GPU cost is then a difference
+// of two published numbers rather than something only a device can see.
+//
+// WHY IT IS RECORDED AND NOT GATED, and this is a scope decision rather than a hedge. ROADMAP.md:23
+// puts "dirty 归属反转（按存储属主键控的发射游标）" in the P3b/P4b cell: P4a lands the flat drain
+// list, and the per-storage-owner emission cursor with view/owner index remapping - which is what
+// actually decides the shape for a texture uploaded through a VIEW - is the next phase's. Gating a
+// shape the phase has not finished deciding would either pin today's shape as if it were the
+// answer, or fail on a change that is the point of the next phase. So P4a BUILDS the scenario (it
+// is meaningless without P4a's records) and runs it as a RECORDED comparison; P3b/P4b turns it into
+// a gate with the Mali frame-time delta published beside it (D-D4).
+//
+// WHAT IT THEREFORE ASSERTS, and it is not nothing:
+//
+//   1. the numbers could be READ AT ALL - the counters exist, the window covers the workload, and
+//      the workload really uploaded (a run that uploaded nothing would record four zeroes and look
+//      exactly like a healthy run whose emitter had been switched off);
+//   2. the internal ARITHMETIC of the server's own bracket holds: emit == box + rect, and
+//      jobs >= emit, because a box emission is one job and a rect-list emission is N;
+//   3. the client and the server agree on the RECORD COUNT when both are non-zero (ctu == emit).
+//      Not "when the client is non-zero": on the P4a contract tree the client emits nothing and
+//      that is a SKIP-shaped observation, not a divergence.
+//
+// Everything else - which shape each texture took, and whether that is the right shape - is
+// RECORDED with RecordProperty and printed, for MEASUREMENTS.md and for the P3b/P4b gate to be
+// written against.
+//
+// THE WORKLOAD is the shape the decision is about: one texture receiving MANY SMALL SCATTERED
+// SUB-REGIONS per frame (the sprite-atlas / chunk-renderer shape), and one receiving a single large
+// contiguous one. The first is where the box-versus-rect choice is made - MipmapStorage's 96-rect
+// cascade and the summedArea*4 >= unionArea*3 union-box fallback - and the second is the control
+// that must always be one box whatever the policy is.
+//
+// DIRECTGLES ONLY. The server-side counters are Espryt's (Managers.cpp:6360-6395); Magma's upload
+// path is P7 and contributes nothing to them, so a DirectVulkan lane would record a bracket of
+// zeroes and call it a shape.
+
+#include <cstdint>
+#include <cstdlib>
+#include <iostream>
+#include <string>
+#include <vector>
+
+#include "../Harness/HeadlessGL.h"
+#include "../Harness/PipeStatsWindow.h"
+#include "../Harness/ScenarioFixture.h"
+
+#ifdef GLAPI
+#undef GLAPI
+#endif
+#define GL_GLEXT_PROTOTYPES
+#include <GL/gl.h>
+#include <GL/glcorearb.h>
+#undef GL_GLEXT_PROTOTYPES
+
+namespace MGITest {
+    namespace {
+
+        // Set by the TextureUploadShape. ctest entry and by nothing else; a harness marker, never
+        // read by the library.
+        constexpr const char* kLaneMarker = "MGITEST_TEXTURE_UPLOAD_SHAPE_LANE";
+
+        constexpr int kInset = 2;
+        constexpr int kAtlasSize = 64;
+        // Enough scattered rects that the box-versus-rect policy has a real decision to make: the
+        // rect cascade caps at MipmapStorage::kMaxDirtyRects = 96, and the union-box fallback fires
+        // on summedArea*4 >= unionArea*3, so a handful of rects would take neither branch
+        // interestingly.
+        constexpr int kScatteredRects = 40;
+        constexpr int kRectSize = 2;
+        constexpr int kFrames = 3;
+
+        constexpr const char* kVS = R"(#version 330 core
+in vec2 aPos;
+out vec2 vUv;
+void main() {
+    vUv = aPos * 0.5 + 0.5;
+    gl_Position = vec4(aPos, 0.0, 1.0);
+}
+)";
+
+        constexpr const char* kFS = R"(#version 330 core
+in vec2 vUv;
+uniform sampler2D uTex;
+out vec4 oColor;
+void main() { oColor = texture(uTex, vUv); }
+)";
+
+        struct Vertex {
+            float x, y;
+        };
+
+        bool BuildMarkerIsSet(const char* name) {
+            const char* value = std::getenv(name);
+            return value != nullptr && value[0] == '1' && value[1] == '\0';
+        }
+
+        class TextureUploadShapeScenario : public ScenarioTest {
+        protected:
+            void SetUp() override {
+                ScenarioTest::SetUp();
+                if (!Ready()) return;
+                std::string error;
+                m_program = CompileProgram(kVS, kFS, &error);
+                ASSERT_NE(m_program, 0u) << error;
+
+                static const Vertex quad[6] = {{-1.0f, -1.0f}, {1.0f, -1.0f}, {1.0f, 1.0f},
+                                               {-1.0f, -1.0f}, {1.0f, 1.0f},  {-1.0f, 1.0f}};
+                glGenBuffers(1, &m_quadBuffer);
+                glBindBuffer(GL_ARRAY_BUFFER, m_quadBuffer);
+                glBufferData(GL_ARRAY_BUFFER, sizeof(quad), quad, GL_STATIC_DRAW);
+                glGenVertexArrays(1, &m_vao);
+                glBindVertexArray(m_vao);
+                glEnableVertexAttribArray(0);
+                glVertexAttribPointer(0, 2, GL_FLOAT, GL_FALSE, sizeof(Vertex), nullptr);
+                glBindVertexArray(0);
+            }
+
+            void TearDown() override {
+                if (!Ready()) return;
+                glUseProgram(0);
+                glBindVertexArray(0);
+                glBindTexture(GL_TEXTURE_2D, 0);
+                glBindBuffer(GL_ARRAY_BUFFER, 0);
+                if (m_scattered != 0) glDeleteTextures(1, &m_scattered);
+                if (m_contiguous != 0) glDeleteTextures(1, &m_contiguous);
+                if (m_vao != 0) glDeleteVertexArrays(1, &m_vao);
+                if (m_quadBuffer != 0) glDeleteBuffers(1, &m_quadBuffer);
+                if (m_program != 0) glDeleteProgram(m_program);
+            }
+
+            void SkipUnlessTheLaneIsAssertableHere() {
+                if (std::getenv(kLaneMarker) == nullptr) {
+                    GTEST_SKIP() << "runs only in its own lane: the TextureUploadShape. ctest entry "
+                                    "sets " << kLaneMarker
+                                 << " together with MOBILEGL_PIPE_STATS=1, "
+                                    "MOBILEGL_PIPE_STATS_PERIOD=1 and a private "
+                                    "MOBILEGL_LOG_FILE_PATH. None of that is configured in the "
+                                    "ambient entries, and the ambient log is shared, so a read here "
+                                    "would race.";
+                    return;
+                }
+                if (Gl().BackendName() != "DirectGLES") {
+                    GTEST_SKIP() << "DirectGLES only: the upload-shape counters are Espryt's "
+                                    "(Managers.cpp:6360-6395) and " << Gl().BackendName()
+                                 << " contributes nothing to them, so this lane would record a "
+                                    "bracket of zeroes and call it a shape.";
+                    return;
+                }
+                if (!BuildMarkerIsSet("MGITEST_PIPE_PUSH_BUILD")) {
+                    GTEST_SKIP() << "this library was built without MOBILEGL_PIPE_PUSH: the client's "
+                                    "half of the comparison (CallClass::ClientTextureUploadEmissions, "
+                                    "the ctu= field) does not exist there, and a one-sided reading is "
+                                    "not the comparison this scenario is for. The entry is registered "
+                                    "in every build so that `ctest -L integration-gpu` names the same "
+                                    "tests in the pull build and the push build (gate G2).";
+                    return;
+                }
+                if (PipeStatsWindow::LibraryLogPath().empty()) {
+                    GTEST_SKIP() << "the lane configured no MOBILEGL_LOG_FILE_PATH, and the library's "
+                                    "summary line is the only channel this module has for reading "
+                                    "PipeStats";
+                    return;
+                }
+            }
+
+            GLuint MakeAtlas(std::uint8_t r, std::uint8_t g, std::uint8_t b) {
+                std::vector<std::uint8_t> texels(static_cast<std::size_t>(kAtlasSize) * kAtlasSize * 4);
+                for (std::size_t i = 0; i < texels.size(); i += 4) {
+                    texels[i] = r;
+                    texels[i + 1] = g;
+                    texels[i + 2] = b;
+                    texels[i + 3] = 255;
+                }
+                GLuint texture = 0;
+                glGenTextures(1, &texture);
+                glBindTexture(GL_TEXTURE_2D, texture);
+                glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA8, kAtlasSize, kAtlasSize, 0, GL_RGBA,
+                             GL_UNSIGNED_BYTE, texels.data());
+                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
+                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
+                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_BASE_LEVEL, 0);
+                glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAX_LEVEL, 0);
+                return texture;
+            }
+
+            Image DrawSampled(GLuint texture) {
+                BindDefaultFramebuffer();
+                glViewport(0, 0, Gl().Width(), Gl().Height());
+                glUseProgram(m_program);
+                glUniform1i(glGetUniformLocation(m_program, "uTex"), 0);
+                glActiveTexture(GL_TEXTURE0);
+                glBindTexture(GL_TEXTURE_2D, texture);
+                glBindVertexArray(m_vao);
+                glDrawArrays(GL_TRIANGLES, 0, 6);
+                return ReadPixels(Gl().Width(), Gl().Height());
+            }
+
+            GLuint m_program = 0;
+            GLuint m_vao = 0;
+            GLuint m_quadBuffer = 0;
+            GLuint m_scattered = 0;
+            GLuint m_contiguous = 0;
+        };
+
+        TEST_F(TextureUploadShapeScenario, TheEmittedUploadShapeIsRecordedAndTheTwoSidesAgree) {
+            if (!Ready()) return;
+            SkipUnlessTheLaneIsAssertableHere();
+            if (IsSkipped()) return;
+
+            m_scattered = MakeAtlas(0, 255, 0);
+            m_contiguous = MakeAtlas(0, 255, 0);
+            // The first draw of each texture uploads its whole level, which is not the shape this
+            // scenario is about; it happens in the SETUP window, before the one that is read.
+            DrawSampled(m_scattered);
+            DrawSampled(m_contiguous);
+            BindDefaultFramebuffer();
+            Gl().EndFrame();
+
+            // ---- the counted window ----
+            Image lastScattered;
+            Image lastContiguous;
+            for (int frame = 0; frame < kFrames; ++frame) {
+                // MANY SMALL SCATTERED RECTS: the shape whose box-versus-rect decision is the whole
+                // subject. They are spread over the atlas on a coarse stride so that their union
+                // box is most of the texture and their summed area is a small fraction of it -
+                // which is the input the summedArea*4 >= unionArea*3 fallback is written for.
+                glBindTexture(GL_TEXTURE_2D, m_scattered);
+                const std::uint8_t patch[kRectSize * kRectSize * 4] = {
+                    0, 255, 0, 255, 0, 255, 0, 255, 0, 255, 0, 255, 0, 255, 0, 255};
+                for (int rect = 0; rect < kScatteredRects; ++rect) {
+                    const int x = ((rect * 7) % (kAtlasSize / kRectSize)) * kRectSize;
+                    const int y = ((rect * 5) % (kAtlasSize / kRectSize)) * kRectSize;
+                    glTexSubImage2D(GL_TEXTURE_2D, 0, x, y, kRectSize, kRectSize, GL_RGBA,
+                                    GL_UNSIGNED_BYTE, patch);
+                }
+                lastScattered = DrawSampled(m_scattered);
+
+                // ONE LARGE CONTIGUOUS REGION: the control. Whatever the policy is, this is one
+                // box and one job, and a reading where it is not says the policy has stopped
+                // looking at the region at all.
+                glBindTexture(GL_TEXTURE_2D, m_contiguous);
+                std::vector<std::uint8_t> band(static_cast<std::size_t>(kAtlasSize) * 8 * 4);
+                for (std::size_t i = 0; i < band.size(); i += 4) {
+                    band[i] = 0;
+                    band[i + 1] = 255;
+                    band[i + 2] = 0;
+                    band[i + 3] = 255;
+                }
+                glTexSubImage2D(GL_TEXTURE_2D, 0, 0, 0, kAtlasSize, 8, GL_RGBA, GL_UNSIGNED_BYTE,
+                                band.data());
+                lastContiguous = DrawSampled(m_contiguous);
+            }
+            ASSERT_EQ(FirstGLError(), GLenum(GL_NO_ERROR)) << "the upload workload left a GL error behind";
+            Gl().EndFrame(); // the swap that emits the window covering exactly the work above
+
+            const PipeStatsWindow::Window window = PipeStatsWindow::LastFromLaneLog();
+            ASSERT_TRUE(window.found)
+                << "no 'MGPipe stats:' line in " << PipeStatsWindow::LibraryLogPath()
+                << ", so the shape could not be read at all";
+            RecordProperty("stats_line", window.line.c_str());
+
+            const long long emissions = PipeStatsWindow::CounterOrAbsent(window, "emit");
+            const long long box = PipeStatsWindow::CounterOrAbsent(window, "box");
+            const long long rect = PipeStatsWindow::CounterOrAbsent(window, "rect");
+            const long long jobs = PipeStatsWindow::CounterOrAbsent(window, "jobs");
+            const long long clientEmissions = PipeStatsWindow::CounterOrAbsent(window, "ctu");
+            ASSERT_GE(emissions, 0) << "the summary line carries no tex[emit=]: " << window.line;
+            ASSERT_GE(box, 0) << "no box=: " << window.line;
+            ASSERT_GE(rect, 0) << "no rect=: " << window.line;
+            ASSERT_GE(jobs, 0) << "no jobs=: " << window.line;
+
+            // THE RECORD. This is the deliverable of this scenario in P4a: a number, in the ctest
+            // XML and in the log, for MEASUREMENTS.md and for the P3b/P4b gate to be written
+            // against. Printed as well as recorded, because a RecordProperty is invisible in a
+            // console run.
+            std::cout << "[ TextureUploadShape ] backend=" << Gl().BackendName() << " frames=" << kFrames
+                      << " scattered_rects_per_frame=" << kScatteredRects
+                      << " server[emit=" << emissions << " box=" << box << " rect=" << rect
+                      << " jobs=" << jobs << "] client[ctu=" << clientEmissions << "]" << std::endl;
+            RecordProperty("server_emissions", static_cast<int>(emissions));
+            RecordProperty("server_box_emissions", static_cast<int>(box));
+            RecordProperty("server_rect_emissions", static_cast<int>(rect));
+            RecordProperty("server_upload_jobs", static_cast<int>(jobs));
+            RecordProperty("client_emissions", static_cast<int>(clientEmissions));
+
+            // 1. the workload really uploaded. Without this the three assertions below are all
+            //    0 == 0 and a run whose emitter was switched off records the same "healthy" shape
+            //    as one that worked.
+            ASSERT_GT(emissions, 0)
+                << "the server counted no texture upload emission at all over " << kFrames
+                << " frames of " << kScatteredRects
+                << " sub-regions each plus a contiguous band. Either the uploads never reached the "
+                   "backend or the counter stopped counting; in both cases every shape number below "
+                   "would be a zero that means nothing. "
+                << window.line;
+
+            // 2. the server bracket's own arithmetic.
+            EXPECT_EQ(box + rect, emissions)
+                << "tex[box=] + tex[rect=] must be tex[emit=]: every emission takes exactly one of "
+                   "the two shapes. " << window.line;
+            EXPECT_GE(jobs, emissions)
+                << "tex[jobs=] must be at least tex[emit=]: a box emission is one driver upload job "
+                   "and a rect-list emission is N. " << window.line;
+
+            // 3. the two sides agree, WHEN THERE ARE TWO SIDES - and "there are two sides" is
+            //    answered by the BUILD, not by the number (review F-m7).
+            //
+            //    ctu= IS ALWAYS PRESENT IN A PUSH BUILD: PipeStats.cpp writes the field whether or
+            //    not anything ever incremented the counter, so `clientEmissions > 0` conflated
+            //    three different trees - "no client emitter exists", "the emitter exists and
+            //    emitted nothing", and "the counter was not published at all" - into one branch
+            //    that asserts nothing and prints a sentence that is only true of the first. Once
+            //    package B's texture emitter lands, an emitter that STOPPED emitting would read
+            //    exactly like no emitter at all and this case would have gone green over it, which
+            //    is the failure mode the whole scenario exists to make impossible.
+            //
+            //    So the discriminator is MGITEST_PIPE_CLIENT_TEXTURE_UPLOAD_EMITTER_PRESENT, the
+            //    build's own content probe for a MG_Impl/Pipe source that emits
+            //    CallClass::ClientTextureUploadEmissions - the same mechanism as every other arming
+            //    decision in this package - and each side of it asserts something real.
+            const bool clientEmitterExists =
+                BuildMarkerIsSet("MGITEST_PIPE_CLIENT_TEXTURE_UPLOAD_EMITTER_PRESENT");
+            ASSERT_GE(clientEmissions, 0)
+                << "the summary line carries no ctu= field at all, in a push build, where PipeStats "
+                   "publishes it unconditionally. The client half of the comparison cannot be read: "
+                << window.line;
+            RecordProperty("client_emitter_present", clientEmitterExists ? 1 : 0);
+            if (clientEmitterExists) {
+                EXPECT_GT(clientEmissions, 0)
+                    << "a MG_Impl/Pipe source emits CallClass::ClientTextureUploadEmissions on this "
+                       "tree, and the SERVER counted " << emissions
+                    << " texture upload emissions for this workload, but the client counted NONE. An "
+                       "emitter that has stopped emitting reads exactly like no emitter at all in "
+                       "this field, which is why this case asks the build rather than the number. "
+                    << window.line;
+                EXPECT_EQ(clientEmissions, emissions)
+                    << "the CLIENT counted " << clientEmissions
+                    << " texture upload records and the SERVER counted " << emissions
+                    << " for the same workload in the same window. The two counting the same records "
+                       "is the entire reason both are published (D-L): a divergence here is an "
+                       "emission-shape divergence that SSIM is blind to and that costs ~+6 ms/frame "
+                       "on Mali when it goes the wrong way. "
+                    << window.line;
+            } else {
+                // Not merely "not asserted": on a tree with no client emitter the counter must be
+                // ZERO, and a non-zero one would mean the probe is looking for the wrong symbol -
+                // i.e. that the arming decision above is wrong and every future run of this case
+                // is mis-armed.
+                EXPECT_EQ(clientEmissions, 0)
+                    << "no MG_Impl/Pipe source emits CallClass::ClientTextureUploadEmissions on this "
+                       "tree, yet the client counted " << clientEmissions
+                    << " of them. Something is incrementing that counter which this build's probe "
+                       "cannot see, so the probe is looking for the wrong symbol and this case's "
+                       "arming decision is unreliable in both directions. " << window.line;
+                std::cout << "[ TextureUploadShape ] no P4a client emitter has landed on this tree "
+                             "(the build's ClientTextureUploadEmissions probe found none), so this "
+                             "run records the SERVER shape only and pins ctu=0. That is the expected "
+                             "reading on the contract tree and it is not a divergence."
+                          << std::endl;
+                RecordProperty("client_side", "absent");
+            }
+
+            // The pixels, so that a recorded shape cannot be the shape of a workload that drew
+            // nothing.
+            EXPECT_TRUE(RegionIsMostly(lastScattered, kInset, lastScattered.Width() - kInset, kInset,
+                                       lastScattered.Height() - kInset, "green", 0.0,
+                                       "the scattered-rect atlas"));
+            EXPECT_TRUE(RegionIsMostly(lastContiguous, kInset, lastContiguous.Width() - kInset, kInset,
+                                       lastContiguous.Height() - kInset, "green", 0.0,
+                                       "the contiguous-band atlas"));
+        }
+
+    } // namespace
+} // namespace MGITest

MobileGL/MG_Pipe/Coverage.def

@@ -195,6 +195,46 @@
 // resolution reads the applier's BoundVertexElements instead of the object - at which point
 // PipeFill.cpp's EmittedCallSuppliesTheWholeField arm is where that is decided, deliberately
 // rather than silently by this row's presence.
+//
+// P4a ADDS SIX ROWS, and the same note applies to every one of them: each is SHAPE-ONLY, each
+// lands in PipeFill.cpp's EmittedCallSuppliesTheWholeField FALSE arm, and the decision is
+// taken THERE rather than inherited from a row's presence here. The rows and their calls:
+//
+//   GetFramebufferBindingSlot -> SetFramebufferState   GetProgramForDraw     -> SetDrawProgram
+//   GetImageTextureBinding    -> SetShaderImages       GetProgramForDispatch -> SetDispatchProgram
+//   GetTextureUnitObject      -> SetSamplerViews       GetMaxTouchedTextureUnit -> SetSamplerViews
+//
+// Five of the six are the pointer-storage case GetBoundVertexArray already documents: the
+// field is a BindingSlot<FramebufferObject>, an ImageTextureBinding, a TextureUnit or a
+// SharedPtr<ProgramObject> - frontend heap references - and the calls carry eight-byte
+// {slot, gen} handles and resolved descriptors. The applier has no way to produce a pointer
+// and P4a deliberately does not give it one; skipping the pull would leave every one of those
+// mirrors null on every draw of every push build. What retires those pulls is not a better
+// applier, it is the phase where the backend stops reading a frontend object at all.
+//
+// THE SIXTH IS A DIFFERENT ARGUMENT AND IT IS WORTH WRITING DOWN, because it looks like the
+// easy one. GetMaxTouchedTextureUnit is a plain Int, and set_sampler_views' Count IS that
+// value plus one (the second merge rule: a high-water mark is directly the count argument).
+// But the set is SUPPRESSED on an unchanged content hash and is emitted only when bit 12 fires,
+// and bit 12's shutter is Mix(textureContent, GetTextureBindGeneration()) - which does NOT
+// move on a redundant re-bind of the object a unit already holds, while the high-water mark
+// DOES (see NoteUnitTouched in DirtySurface.def). So the applier's Count can lag the frontend's
+// high-water mark by exactly the case the suppressor exists to swallow, and the field keeps
+// being pulled. Narrowing that is P3b/P4b's, with the backend debounce it takes over.
+//
+// FOUR ACCESSORS THAT MAP TO A P4a CALL ARE DELIBERATELY NOT HERE, for GetPixelStoreParameters'
+// reason - a row here says "this field is supplied", and for these it would be a half-truth:
+//   GetActiveTextureUnit  - glActiveTexture's selector. set_sampler_views carries the RESOLVED
+//     per-unit set and no active-unit selector at all; nothing on the wire carries it.
+//   GetTextureContextId   - a context identity the backend keys its own tables on. No call
+//     carries it and none should: it is the server's question about the client, not state.
+//   GetTextureBindGeneration / GetSamplingResolutionGeneration - frontend SHUTTERS. What
+//     replaces them server-side is the applier's own Serial, which is a different value with a
+//     different owner; claiming the sets supply the generations would make the fill loop skip
+//     two counters no record carries.
+// And GetTextureObject / GetProgramObject are STICKY (see MGP_COVERAGE_STICKY_LIST): they are
+// keyed by GL name, they are object lookups rather than verb state, and a forwarded field has
+// no storage for an emitted call to supply.
 #define MGP_COVERAGE_EMITTED_LIST(X)                                     \
     X(GetBlendColor,                            SetDynamicState)         \
     X(GetBlendEquationIndexed,                  CreateRenderState)       \
@@ -210,8 +250,11 @@
     X(GetDepthFunc,                             CreateRenderState)       \
     X(GetDepthMask,                             CreateRenderState)       \
     X(GetDepthRangeIndexed,                     SetDynamicState)         \
+    X(GetFramebufferBindingSlot,                SetFramebufferState)     \
+    X(GetImageTextureBinding,                   SetShaderImages)         \
     X(GetLineWidth,                             SetDynamicState)         \
     X(GetLogicOp,                               CreateRenderState)       \
+    X(GetMaxTouchedTextureUnit,                 SetSamplerViews)         \
     X(GetMinSampleShadingValue,                 CreateRenderState)       \
     X(GetPatchDefaultInnerLevel,                SetPatchState)           \
     X(GetPatchDefaultOuterLevel,                SetPatchState)           \
@@ -221,11 +264,14 @@
     X(GetPolygonOffsetFactor,                   SetDynamicState)         \
     X(GetPolygonOffsetUnits,                    SetDynamicState)         \
     X(GetPrimitiveRestartIndex,                 SetDynamicState)         \
+    X(GetProgramForDispatch,                    SetDispatchProgram)      \
+    X(GetProgramForDraw,                        SetDrawProgram)          \
     X(GetProvokingVertexMode,                   CreateRenderState)       \
     X(GetRenderStateParameters,                 CreateRenderState)       \
     X(GetRenderStateParametersVersion,          BindRenderState)         \
     X(GetScissorBox,                            SetDynamicState)         \
     X(GetStencilState,                          CreateRenderState)       \
+    X(GetTextureUnitObject,                     SetSamplerViews)         \
     X(GetViewport,                              SetDynamicState)         \
     X(GetViewportIndexed,                       SetDynamicState)         \
     X(IsCapabilityEnabled,                      CreateRenderState)       \

MobileGL/MG_Pipe/DirtySurface.def

@@ -154,6 +154,21 @@
 // The gate is therefore a COMPLETENESS gate over what the scanner does see. The semantic
 // proof stays the MOBILEGL_PIPE_VERIFY lane, which is blind to none of them.
 //
+// THE MUTATOR PREFIX SET WIDENS AT P4a, and what it does NOT gain is the more interesting
+// half. `pGLContext->` + Add|Set|Mark|Bump|Allocate|Truncate|Record|Notify|Begin|End could
+// not see `UseProgram`, `BindVertexArray`, `BindProgramPipelineObject` or
+// `BindTransformFeedbackObject` - four mutators that each move a field P3a or P4a pushes -
+// because none of them starts with one of those words. `Use` and `Bind` are added, and the
+// complete set the widening surfaces was enumerated by grep at the phase's base ref so it
+// cannot surprise anybody: exactly those four names, on seven call sites.
+//
+// `Create*` and `Pop*` are DELIBERATELY NOT ADDED. They create or destroy objects rather than
+// move a pushed field, and each object class's creation and destruction is already answered
+// twice over - by its own Mark*ForDeletion row below and by the constructor-time
+// resource_create - so adding them would produce rows that restate an answer this file already
+// gives, and every one of them would have to be maintained against a mechanism that is not
+// theirs. A gate whose rows do not each carry their own question is a gate nobody reads.
+//
 // clang-format off
 
 // X(Mutator, Answer)
@@ -279,6 +294,39 @@
     /* so the honest answer is the pull. Narrowing it is P3b's, when it takes the subsystem */  \
     /* over and the binding points get a generation of their own.                           */ \
     X(SetNamedTransformFeedbackBinding,   kPulledEveryVerb)                                     \
+    /* ---- P4a, THE FOUR THE WIDENED PREFIX SET SURFACES. Every one of them moves a field */  \
+    /* P3a or P4a pushes and none of them was visible to the scan before, because none     */  \
+    /* begins with one of the ten words the pattern matched.                                */ \
+    /*   UseProgram is bit 6's whole subject: the shutter is                                */ \
+    /*     Mix(GetCurrentProgram()->GetLifetimeId(), GetLinkVersion()) and glUseProgram is  */  \
+    /*     what moves the object it reads through. Two call sites. AND SINCE THE FABLE     */  \
+    /*     SEAM ROUND (F-1 / F-2) IT IS BITS 12 AND 14's TOO: set_sampler_views is         */  \
+    /*     resolved for the program in use and set_shader_images' window is the highest    */  \
+    /*     image unit the program in use names, so both shutters mix the same identity     */  \
+    /*     bit 6 reads, and a glUseProgram alone moves all three. Undecided for the same    */  \
+    /*     reason as bit 6 (the taint below), marked the same way.                          */  \
+    /*   BindVertexArray is bit 5's, for the same reason one level down: the shutter mixes  */  \
+    /*     the bound VAO's identity with its configuration version, and this is the bind.   */  \
+    /*     Three call sites.                                                                */ \
+    X(UseProgram,                         NEW_SHADER|NEW_SAMPLER_VIEWS|NEW_SHADER_IMAGES)      \
+    X(BindVertexArray,                    NEW_VERTEX_ELEMENTS)                                 \
+    /* NOT NEW_SHADER, and the derivation refutes it outright rather than leaving it a      */  \
+    /* judgement: this mutator writes m_boundProgramPipeline (plus the pipeline name table) */  \
+    /* and bit 6's shutter reads m_currentProgram's lifetime id and link version - disjoint */  \
+    /* sets, on every path. That is not an oversight in the shutter either: it reads        */  \
+    /* GetCurrentProgram() and DELIBERATELY NOT GetProgramForDraw(), because the tracker    */  \
+    /* must not force a compile just to answer "did the shader move", and flattening a      */  \
+    /* pipeline into its composite is exactly the compile it would force. What a bind moves */  \
+    /* is which program the validate point will flatten, and that field -                   */  \
+    /* GetProgramForDraw - is in the may-read mask of every class that draws and is copied  */  \
+    /* by the residual fill at every verb of those classes, EMITTED-AND-STILL-PULLED like   */  \
+    /* GetBoundVertexArray. So the pull is what holds on every path, and it is the answer.  */ \
+    X(BindProgramPipelineObject,          kPulledEveryVerb)                                    \
+    /* No shutter at all, and none is needed: the transform-feedback binding reaches the    */  \
+    /* backend through GetBoundTransformFeedbackLifetimeId and its siblings, which are in   */  \
+    /* the kDraw and kXfbSpan may-read masks, so the residual fill copies them at every     */  \
+    /* verb of those classes. Narrowing it is P4b's, with set_stream_output_targets.        */ \
+    X(BindTransformFeedbackObject,        kPulledEveryVerb)                                    \
     /* ---- an object's death: no generation, because there is no longer an object  */          \
     /* to carry one. Espryt 0b's delete_* / resource_destroy publishes the kinds     */         \
     /* that have a handle on the wire; programs, program pipelines and shaders have  */         \
@@ -296,9 +344,24 @@
     /*     Destroyed consumer, package espryt), not the client's: the client mints   */        \
     /*     the CSO handle and emits create/bind, and the free rides with that        */        \
     /*     consumer. Until it lands the row states the design, not the tree.         */        \
+    /* P4a CLOSES ONE OF THE THREE HOLES ABOVE AND STATES WHY THE OTHER TWO ARE NOT HOLES.  */ \
+    /*   MarkProgramForDeletion -> kExplicitDestroy. delete_shader_state exists now and     */  \
+    /*     ~ProgramObject emits it through the client-side death helper, in the fixed       */  \
+    /*     order: the wire delete first, the backend notice second, the slot free last. A   */  \
+    /*     program pipeline COMPOSITE takes the same call on the same helper - the server   */  \
+    /*     never learns it is a composite.                                                  */ \
+    /*   MarkProgramPipelineForDeletion stays kUnpublishedDestroy, and it is NOT waiting    */  \
+    /*     for a later phase: a ProgramPipelineObject has no lifetime id and no wire object */  \
+    /*     at all (its only identity is m_everBound). It never gets a handle, so there is   */  \
+    /*     nothing for a delete to name. What its cache's eviction DOES publish is the      */  \
+    /*     composite's delete_shader_state, which is the row above.                         */ \
+    /*   MarkShaderForDeletion stays kUnpublishedDestroy for the same kind of reason: a     */  \
+    /*     ShaderObject has no lifetime id and never crosses the boundary - the payload is  */  \
+    /*     per-stage SPIR-V plus the reflection archive, not source, and glslang lives      */  \
+    /*     entirely on the client.                                                          */ \
     X(MarkBufferObjectForDeletion,        kExplicitDestroy)                                     \
     X(MarkFramebufferObjectForDeletion,   kExplicitDestroy)                                     \
-    X(MarkProgramForDeletion,             kUnpublishedDestroy)                                  \
+    X(MarkProgramForDeletion,             kExplicitDestroy)                                     \
     X(MarkProgramPipelineForDeletion,     kUnpublishedDestroy)                                  \
     X(MarkRenderbufferObjectForDeletion,  kExplicitDestroy)                                     \
     X(MarkSamplerObjectForDeletion,       kExplicitDestroy)                                     \
@@ -326,9 +389,36 @@
 // UNDECIDED, each with the reason --check prints for it. Every bit answer NOT listed here
 // is marked derived: --check fails when the derivation cannot decide it, and fails again
 // when a mark here names a pair the derivation now decides, so this list can neither hide a
-// row nor outlive its reason. Empty today: every bit answer above is supported at field
-// level. The ten mutators that reach a tainted body (--check prints the count) all carry a
-// prose answer, which no derivation checks.
-#define MGP_DIRTY_SURFACE_UNDECIDED_LIST(X)
+// row nor outlive its reason.
+//
+// IT WAS EMPTY UNTIL P4a, and it stops being empty for a reason that is a property of the
+// SCANNER rather than of the rows. Every entry below is a bit answer that is plainly true -
+// glUseProgram is what moves the object bits 6, 12 and 14's shutters read through (the
+// program in use; bits 12 and 14 since the fable seam round, F-1 / F-2), and glBindVertexArray
+// is what moves the object bit 5's shutter reads through - and the write analysis cannot say
+// so, because each of the two mutators reaches, BY NAME, a body that writes a member with no
+// m_ prefix:
+//
+//   UseProgram      -> DestroyProgramSlot() writes `attachedShaders`
+//   BindVertexArray -> a call spelled `Bind(` resolves to every body of that name, one of
+//                      which (ImageTextureBinding::Bind) writes `Access`
+//
+// A call resolved by name to every body of that name is one of the three over-approximations
+// this analysis documents about itself, and an unplaceable write TAINTS the body it is in -
+// which is the right default, because "it does not write anything the shutter reads" must
+// never be claimed about code the script could not read. Widening the taint rule to ignore
+// non-m_ writes would weaken the one mechanism that catches a genuine under-fire, so the rows
+// are MARKED, with the tool's own reason, rather than the tool being made more permissive.
+// Control 21 is what proves every marked row still needs its mark (it reads this list, so a
+// row that gains a bit here is counted rather than assumed), and control 18 is what fails the
+// moment any of them becomes decidable and the mark outlives its reason.
+//
+// The ten mutators that reach a tainted body (--check prints the count) all carry a prose
+// answer, which no derivation checks; these two mutators are the first that carry a bit answer.
+#define MGP_DIRTY_SURFACE_UNDECIDED_LIST(X)                                                     \
+    X(UseProgram,      NEW_SHADER)                                                              \
+    X(UseProgram,      NEW_SAMPLER_VIEWS)                                                       \
+    X(UseProgram,      NEW_SHADER_IMAGES)                                                       \
+    X(BindVertexArray, NEW_VERTEX_ELEMENTS)
 
 // clang-format on

MobileGL/MG_Pipe/MGPipe.h

@@ -83,7 +83,30 @@ namespace MobileGL::MG_Pipe {
     // the other.
     inline constexpr Uint64 kMGPipeSubsystemResources = 1ull << 7;
     inline constexpr Uint64 kMGPipeSubsystemVertexInput = 1ull << 8;
-    // bits 9..62 reserved for the later phases, allocated in ROADMAP order.
+    // P4a's four. FOUR AND NOT ONE, for P3a's reason one level out: a framebuffer path that
+    // regressed, a texture path that regressed, a sampler path that regressed and a program
+    // path that regressed are four different findings, and clearing one must not disarm the
+    // other three.
+    //
+    // THREE OF THEM HAVE A DEPENDENCY and it is diagnosed at the first use, never half-run -
+    // one Resolve<Family>SubsystemArm per family beside the backend's existing
+    // ResolveResourceSubsystemArm, modelled on the bit-8-requires-bit-7 refusal it already
+    // ships, and lazy rather than at bring-up because a pre-flight child dying on a signal
+    // makes a whole lane SKIP green: bit 11 requires bit 10 because
+    // every MGPBoundView::Texture and MGPImageView::Res names a Texture handle and only bit 10
+    // puts one in the slot table; bit 9 requires bit 10 because MGPSurface::Res does; and bit
+    // 10 requires bit 7 because a buffer texture's BufferForTexBuffer names a Buffer handle.
+    // The mirror pairs (10 without 11, 10 without 9, 7 without 10) are all fine, and are
+    // stated as such because an unreachable branch that says something different is how the
+    // reachable one drifts. Bit 12 depends on nothing.
+    inline constexpr Uint64 kMGPipeSubsystemFramebuffer = 1ull << 9;       // set_framebuffer_state
+    inline constexpr Uint64 kMGPipeSubsystemTextureResources = 1ull << 10; // texture + renderbuffer
+                                                                          // resource_*, set_texture_params
+    inline constexpr Uint64 kMGPipeSubsystemSamplers = 1ull << 11;         // sampler CSO, sampler view,
+                                                                          // the three unit sets
+    inline constexpr Uint64 kMGPipeSubsystemPrograms = 1ull << 12;         // shader CSO, draw/dispatch
+                                                                          // program, global constants
+    // bits 13..62 reserved for the later phases, allocated in ROADMAP order.
     // NOT a subsystem, a BEHAVIOUR: turn OFF client-side content addressing of CSOs, so
     // every pipeline-version change mints a fresh CSO and the map is never probed. This is
     // the negative control the whole CSO design is measured against (ROADMAP.md P2).
@@ -93,6 +116,14 @@ namespace MobileGL::MG_Pipe {
     // "everything P2 had and nothing of mine" arm is spelled MOBILEGL_PIPE_PUSH=0x7f.
     inline constexpr Uint64 kMGPipeSubsystemsMigratedAtP2 = 0x7full;   // bits 0..6
     inline constexpr Uint64 kMGPipeSubsystemsMigratedAtP3a = 0x1ffull; // bits 0..8
+    // P4a's, and the two above are NOT edited: 0x1ff is P4a's T2 arm and its "everything P3a
+    // had and nothing of mine" control, exactly as 0x7f was P3a's.
+    inline constexpr Uint64 kMGPipeSubsystemsMigratedAtP4a = 0x1fffull; // bits 0..12
+    static_assert(kMGPipeSubsystemsMigratedAtP4a ==
+                      (kMGPipeSubsystemsMigratedAtP3a | kMGPipeSubsystemFramebuffer |
+                       kMGPipeSubsystemTextureResources | kMGPipeSubsystemSamplers |
+                       kMGPipeSubsystemPrograms),
+                  "the P4a phase constant and P4a's four subsystem bits have drifted");
 
     // The catalogue itself. Only macros, so it is safe to expand inside the namespace, and
     // consumers (the unit test, later the transport) get MGP_CALL_LIST from this header.

MobileGL/MG_Pipe/MGPipeHandles.h

@@ -85,6 +85,17 @@ namespace MobileGL::MG_Pipe {
     // a pipeline object, and the server never learns it is a composite - it is just another
     // ShaderCso. Reserving a band rather than a flag keeps the composite resolver's
     // lifetime bookkeeping out of the ordinary program slot allocator.
+    //
+    // THE ONE ENTRY POINT INTO THE BAND is MGPipeSlotAllocator::AllocateComposite(lifetimeId)
+    // (MG_Impl/Pipe/SlotAllocator.h, P4a D-H7). MGPipeSlotAllocator::Allocate REFUSES the band
+    // for kind ShaderCso, which is what makes "an ordinary program can never be handed a
+    // composite slot" a property of the allocator rather than of its callers; the band carries
+    // its own exhaustion assert, so exhausting it is a named Fatal rather than silent slot
+    // theft from ordinary programs. A composite's slot has TWO independent release paths - the
+    // pipeline cache's LRU eviction and the composite ProgramObject's own destructor - and
+    // both go through one client-side death helper (MG_Pipe/PipeMutation.h's
+    // MGPipeEmitShaderCsoDestroyAndFree), whose second call is a proven no-op because Free
+    // refuses a slot that is not live at that generation.
     inline constexpr Uint32 kMGPipeShaderCsoSlotLimit = 1u << 20;
     inline constexpr Uint32 kMGPipeShaderCsoCompositeSlotBase =
         kMGPipeShaderCsoSlotLimit - (kMGPipeShaderCsoSlotLimit >> 4);

MobileGL/MG_Pipe/MGPipeTypes.h

@@ -145,15 +145,152 @@ namespace MobileGL::MG_Pipe {
     static_assert(sizeof(MGPCaps) == sizeof(DynamicBackendParameters) + 8 + 24 + 24,
                   "MGPCaps gained padding or a member; update the wire format");
 
+    // ---------------------------------------------------------------------------------
+    // MGPResourceDesc's two discriminators (P4a, D-A3 / D-A4)
+    // ---------------------------------------------------------------------------------
+
+    // MGPResourceDesc::Target. P3a minted no enum for this list because it had exactly one
+    // producer and used the leading member's value (0) for it; P4a's texture family is the
+    // second producer, so the list is written out here, beside the field, in the order the
+    // field's own comment already wrote it.
+    //
+    // TexRect IS A THIRTEENTH ENUMERATOR AND THE BRIEF'S LIST HAS TWELVE. MobileGL's
+    // TextureTarget has TextureRectangle (MG_State/GLState/TextureState/TextureEnum.h), the
+    // table below may not have a `default:` arm, and folding rectangle onto Tex2D would erase
+    // a distinction the frontend keeps and both backends switch on (Espryt's
+    // MapToBackendTextureTarget lowers Tex1D the same way and Tex1D still has its own
+    // enumerator here). It is appended AFTER TexBuffer so every value the design document
+    // names keeps the number it was given.
+    enum class MGPipeResourceTarget : Uint8 {
+        Buffer = 0,
+        Tex1D,
+        Tex2D,
+        Tex3D,
+        Tex1DArray,
+        Tex2DArray,
+        TexCube,
+        TexCubeArray,
+        Tex2DMS,
+        Tex2DMSArray,
+        Renderbuffer,
+        TexBuffer,
+        TexRect,
+        Count,
+    };
+
+    // P3a's constant, moved here from MG_Impl/Pipe/ResourceTracker.h with the enum: the ack
+    // predicate at the bottom of this header now names the buffer target explicitly (D-A2) and
+    // may not reach into MG_Impl to do it. The static_assert is what keeps the two spellings
+    // from drifting; nothing may open-code either.
+    inline constexpr Uint8 kMGPipeResourceTargetBuffer =
+        static_cast<Uint8>(MGPipeResourceTarget::Buffer);
+    static_assert(kMGPipeResourceTargetBuffer == static_cast<Uint8>(MGPipeResourceTarget::Buffer),
+                  "P3a's kMGPipeResourceTargetBuffer and MGPipeResourceTarget::Buffer have drifted");
+
+    // A sentinel the table below returns for a TextureTarget enumerator it does not name. It
+    // is NOT a legal Target value - it does not fit the field's Uint8 - so an unmapped
+    // enumerator is a build break at the static_assert rather than a descriptor that quietly
+    // describes the wrong kind of storage. Exactly kMGPipeBindUnmapped's shape.
+    inline constexpr Uint32 kMGPipeResourceTargetUnmapped = 0x100u;
+
+    // The one table. No `default:` arm on purpose - that is what makes the static_assert
+    // below able to see an unnamed enumerator, and it is the shape
+    // MGPipeBindMaskForBufferTarget already uses for BufferTarget.
+    constexpr Uint32 MGPipeResourceTargetForTextureTarget(MobileGL::TextureTarget target) {
+        switch (target) {
+        case MobileGL::TextureTarget::Texture1D:
+            return static_cast<Uint32>(MGPipeResourceTarget::Tex1D);
+        case MobileGL::TextureTarget::Texture2D:
+            return static_cast<Uint32>(MGPipeResourceTarget::Tex2D);
+        case MobileGL::TextureTarget::Texture3D:
+            return static_cast<Uint32>(MGPipeResourceTarget::Tex3D);
+        case MobileGL::TextureTarget::TextureCubeMap:
+            return static_cast<Uint32>(MGPipeResourceTarget::TexCube);
+        // Its own enumerator rather than Tex2D: see the enum's comment.
+        case MobileGL::TextureTarget::TextureRectangle:
+            return static_cast<Uint32>(MGPipeResourceTarget::TexRect);
+        case MobileGL::TextureTarget::Texture2DMultisample:
+            return static_cast<Uint32>(MGPipeResourceTarget::Tex2DMS);
+        case MobileGL::TextureTarget::TextureBuffer:
+            return static_cast<Uint32>(MGPipeResourceTarget::TexBuffer);
+        case MobileGL::TextureTarget::Texture1DArray:
+            return static_cast<Uint32>(MGPipeResourceTarget::Tex1DArray);
+        case MobileGL::TextureTarget::Texture2DArray:
+            return static_cast<Uint32>(MGPipeResourceTarget::Tex2DArray);
+        case MobileGL::TextureTarget::TextureCubeMapArray:
+            return static_cast<Uint32>(MGPipeResourceTarget::TexCubeArray);
+        case MobileGL::TextureTarget::Texture2DMultisampleArray:
+            return static_cast<Uint32>(MGPipeResourceTarget::Tex2DMSArray);
+        // NOT TEXTURE TARGETS. Listed rather than defaulted so the completeness assert still
+        // sees them, and mapped to the sentinel because no descriptor may carry either: the
+        // count is the enum's bound and Unknown is what an unresolved GL enum becomes.
+        case MobileGL::TextureTarget::TextureTargetCount:
+        case MobileGL::TextureTarget::Unknown:
+            return kMGPipeResourceTargetUnmapped;
+        }
+        return kMGPipeResourceTargetUnmapped;
+    }
+
+    constexpr Bool MGPipeEveryTextureTargetIsMapped() {
+        for (SizeT i = 0; i < static_cast<SizeT>(MobileGL::TextureTarget::TextureTargetCount); ++i) {
+            if (MGPipeResourceTargetForTextureTarget(static_cast<MobileGL::TextureTarget>(i)) ==
+                kMGPipeResourceTargetUnmapped) {
+                return false;
+            }
+        }
+        return true;
+    }
+    static_assert(MGPipeEveryTextureTargetIsMapped(),
+                  "a TextureTarget enumerator has no MGPResourceDesc::Target row: add it to "
+                  "MGPipeResourceTargetForTextureTarget, and give it an enumerator of its own "
+                  "rather than folding it onto a neighbour (D-A3)");
+    static_assert(MGPipeResourceTargetForTextureTarget(MobileGL::TextureTarget::Texture2D) !=
+                      MGPipeResourceTargetForTextureTarget(MobileGL::TextureTarget::TextureRectangle),
+                  "a rectangle texture is not a 2D texture on the wire; both backends switch on "
+                  "the difference");
+
+    // MGPResourceDesc::BindMask's twelve bits, in the order the field's comment names them.
+    //
+    // THEY LIVED IN MG_Impl/Pipe/ResourceTracker.h THROUGH P3a, with that file's own note
+    // saying "the integrator moves them beside the field when a second producer appears
+    // (P4a's texture family)". P4a is that producer: a texture sets kMGPipeBindSampler,
+    // kMGPipeBindShaderImage, kMGPipeBindRenderTarget and kMGPipeBindDepthStencil, which are
+    // the four bits nothing set before. The mask is STICKY - ORed, never cleared - and is
+    // emitted on both resource_create and every resource_respecify.
+    enum MGPipeBindBit : Uint16 {
+        kMGPipeBindNone = 0,
+        kMGPipeBindVertex = 1u << 0,
+        kMGPipeBindIndex = 1u << 1,
+        kMGPipeBindConstant = 1u << 2,
+        kMGPipeBindShaderBuffer = 1u << 3,
+        kMGPipeBindIndirect = 1u << 4,
+        kMGPipeBindSampler = 1u << 5,
+        kMGPipeBindShaderImage = 1u << 6,
+        kMGPipeBindRenderTarget = 1u << 7,
+        kMGPipeBindDepthStencil = 1u << 8,
+        kMGPipeBindStreamOutput = 1u << 9,
+        kMGPipeBindAtomic = 1u << 10,
+        // THE D-B7 SWITCH. With kCapNeedsHostIndexBytes set the server mirrors this
+        // resource's bytes so it can rewrite restart indices and flatten multi-draws
+        // (ARCHITECTURE.md 10.3). Getting it wrong is invisible in monolith and silently
+        // disables both under split, which is why it is set from a table rather than from a
+        // special case at the emission site.
+        kMGPipeBindElementArray = 1u << 11,
+    };
+
     // Discriminated resource descriptor: buffers, every texture target and renderbuffers
     // share one create/respecify shape (section 4.5.1).
     struct MGPResourceDesc {
         MGPipeHandle Resource;
-        Uint8 Target;      // Buffer | Tex1D..TexCubeArray | Tex2DMS.. | Renderbuffer | TexBuffer
+        // MGPipeResourceTarget: Buffer | Tex1D..TexCubeArray | Tex2DMS.. | Renderbuffer |
+        // TexBuffer | TexRect. Never open-coded; the texture half comes from
+        // MGPipeResourceTargetForTextureTarget above.
+        Uint8 Target;
         Uint8 StorageKind; // == TextureStorageType (Mipmap | Buffer)
-        // VERTEX|INDEX|CONSTANT|SHADER_BUFFER|INDIRECT|SAMPLER|SHADER_IMAGE|RENDER_TARGET|
-        // DEPTH_STENCIL|STREAM_OUTPUT|ATOMIC|ELEMENT_ARRAY. The ELEMENT_ARRAY bit is the
-        // D-B7 switch: with kCapNeedsHostIndexBytes set the server mirrors this resource.
+        // MGPipeBindBit, above: VERTEX|INDEX|CONSTANT|SHADER_BUFFER|INDIRECT|SAMPLER|
+        // SHADER_IMAGE|RENDER_TARGET|DEPTH_STENCIL|STREAM_OUTPUT|ATOMIC|ELEMENT_ARRAY. The
+        // ELEMENT_ARRAY bit is the D-B7 switch: with kCapNeedsHostIndexBytes set the server
+        // mirrors this resource.
         Uint16 BindMask;
         Uint32 InternalFormat; // already resolved to an uncompressed fallback by the client
         Uint32 Width, Height, Depth;
@@ -161,19 +298,99 @@ namespace MobileGL::MG_Pipe {
         Uint8 FixedSampleLocations, Immutable;
         Uint32 Usage;        // BufferUsage
         Uint32 StorageFlags; // glBufferStorage flags
-        Uint8 HasDefinedContent;  // false after a NULL-data respecify
+        Uint8 HasDefinedContent;  // false after a NULL-data respecify - STORAGE-DEFINING
         Uint8 ImageBindableHint;  // client-side everImageBound; pre-emptive allocation
-        Uint16 Pad0;
+        // THE SCOPE OF A RESPECIFY (P5 R-13.3b, CONTRACT-P5.md table 1 row 19b). Zero means
+        // "this respecify redefines the WHOLE resource"; non-zero means it redefines exactly
+        // the (RespecifiedUploadTarget, RespecifiedLevel) pair below and nothing else.
+        //
+        // It exists because the applier ALREADY takes that scope - as a trailing
+        // const MGPRespecifiedLevel* (PipeApply.h:792-795) - and MGPResourceDesc could not
+        // express it, so it was the second of resource_respecify's two companions with no wire
+        // carrier. The difference is not cosmetic: a null scope drops EVERY pending upload,
+        // because every level's coordinate system has just been replaced, while a per-level
+        // one drops only that key. Crossing without the scope would make every mutable
+        // per-level glTexImage*D on the far side look like a whole-resource redefinition and
+        // silently eat the texels of every other level - exactly the loss the server-side
+        // pending-upload set exists to prevent.
+        //
+        // READ IT THROUGH THE THREE HELPERS BELOW, never by touching the fields: the
+        // presence byte and the pair are one value in three pieces, and an open-coded reader
+        // that forgets the presence byte reads level 0 of upload target 0 as a real scope.
+        //
+        // NOT STORAGE-DEFINING, and not metadata either: it does not describe the resource at
+        // all, it describes what this CALL replaces. MGPipeResourceRespecifyNeedsAck and the
+        // storage-defining field set below are unaffected by it, which is why it is not named
+        // in either.
+        Uint8 HasRespecifiedLevel;
+        Uint8 Pad0;
+        // ImageBindableHint and BindMask above are the two METADATA fields the rule exists
+        // for: a respecify that moves only them - every storage-defining field equal to the
+        // stored descriptor - is a metadata update, with no reallocation ack and no
+        // PendingUploads clear. The rule, the full storage-defining field set and the third
+        // field allowed to differ (GlNameForDiag) are stated beside
+        // MGPipeResourceRespecifyNeedsAck below (P4a, ID-18 M4), which is where the applier
+        // and both twins read them from.
         // Diagnostics only. A GL name is NEVER an identity, never a memo key and never part
         // of a content hash (section 4.2.1). Widened from the plan's two bytes, which
         // cannot hold one.
         Uint32 GlNameForDiag;
-        Uint32 Pad1;
+        // The pair HasRespecifiedLevel above gates. Byte for byte the two members of
+        // MGPRespecifiedLevel (PipeApply.h:792-795), in that order, so the applier's existing
+        // struct and this carrier are one layout - but spelled as two Uint16s rather than as
+        // that type, because PipeApply.h includes THIS header and not the other way round.
+        Uint16 RespecifiedUploadTarget;
+        Uint16 RespecifiedLevel;
         MGPipeHandle ViewOf;             // storage owner for a texture view
         MGPipeHandle BufferForTexBuffer; // texture-buffer backing store
         Uint64 BufOffset, BufSize;       // kWholeBuffer == ~0, resolved live
     };
     MGP_ASSERT_POD(MGPResourceDesc, 88);
+    // The scope fields went into the two existing pads, so the descriptor did not grow and this
+    // number did not move. That was the deciding argument against giving MGPResourceDesc an
+    // MGPBlobRef for the OTHER uncarried companion (initialBytes): a blobref is 24 bytes, the
+    // pads are 6, and it would have taken the struct to 112. The scope needs 5 and fits.
+    static_assert(offsetof(MGPResourceDesc, RespecifiedUploadTarget) + sizeof(Uint16) ==
+                      offsetof(MGPResourceDesc, RespecifiedLevel),
+                  "the respecify scope pair must stay adjacent and in MGPRespecifiedLevel's order");
+
+    // ---- the only supported reads of the respecify scope --------------------------------
+    //
+    // Three fields, one value. Open-coding them is how a reader that forgets the presence byte
+    // turns "whole resource" into "upload target 0, level 0" - a real scope, and the wrong one.
+
+    // True when this respecify replaces the whole resource, which is every glBufferData, every
+    // glBufferStorage, every glTexStorage* and every texture view. The applier drops every
+    // pending upload for it.
+    inline constexpr Bool MGPipeRespecifyIsWholeResource(const MGPResourceDesc& desc) {
+        return desc.HasRespecifiedLevel == 0;
+    }
+
+    // The single (uploadTarget, level) a per-level respecify replaces. Reading either half of a
+    // whole-resource descriptor is a caller error; both answer 0 so that a misuse is at least
+    // deterministic rather than whatever the pad happened to hold.
+    inline constexpr Uint16 MGPipeRespecifiedUploadTargetOf(const MGPResourceDesc& desc) {
+        return MGPipeRespecifyIsWholeResource(desc) ? Uint16(0) : desc.RespecifiedUploadTarget;
+    }
+    inline constexpr Uint16 MGPipeRespecifiedLevelOf(const MGPResourceDesc& desc) {
+        return MGPipeRespecifyIsWholeResource(desc) ? Uint16(0) : desc.RespecifiedLevel;
+    }
+
+    // The two writers. A producer sets the scope with one call so the presence byte cannot be
+    // left behind, and clears it with the other; a descriptor built by value-initialization is
+    // already whole-resource, which is the safe default and the only one P5 produces.
+    inline constexpr void MGPipeSetRespecifiedLevel(MGPResourceDesc& desc, Uint16 uploadTarget,
+                                                   Uint16 level) {
+        desc.HasRespecifiedLevel = 1;
+        desc.RespecifiedUploadTarget = uploadTarget;
+        desc.RespecifiedLevel = level;
+    }
+    inline constexpr void MGPipeClearRespecifiedLevel(MGPResourceDesc& desc) {
+        desc.HasRespecifiedLevel = 0;
+        desc.RespecifiedUploadTarget = 0;
+        desc.RespecifiedLevel = 0;
+    }
+
     inline constexpr Uint64 kMGPipeWholeBuffer = ~0ull;
 
     struct MGPFenceWait {
@@ -304,18 +521,49 @@ namespace MobileGL::MG_Pipe {
     MGP_ASSERT_POD(MGPSamplerView, 36);
 
     // Per texture OBJECT, independent of any view.
+    //
+    // P4a, D-E1: 32 -> 40 bytes. BuiltinSampler is the SamplerCso carrying the
+    // SamplerParameters of the SamplerObject every ITextureObject owns
+    // (TextureState/TextureObject.h's m_sampler, constructed by TextureObjectBase's
+    // constructor). GL 4.6 core table 23.18 makes filter/wrap/compare/border SAMPLER state,
+    // and Espryt pushes it with glTexParameter* onto the TEXTURE rather than with
+    // glBindSampler onto the unit - behaviour P4a preserves exactly. Naming the CSO rather
+    // than widening this payload with a filter/wrap/border block is what keeps ONE authority
+    // for one value: SyncTextureParamsToBackend reads this record, SyncBuiltinSamplerToBackend
+    // reads that CSO's SamplerParameters, and the two pushes stay two pushes.
     struct MGPTextureParams {
-        MGPipeHandle Res;
-        Uint16 BaseLevel, MaxLevel;
-        Uint8 Swizzle[4];
-        Uint8 DepthStencilMode;
+        MGPipeHandle Res;            //  0
+        // Kind SamplerCso. kMGPipeNullHandle is ILLEGAL - every texture object owns a sampler
+        // object, so a null here is Fatal{ProtocolCorruption} rather than "no sampler".
+        MGPipeHandle BuiltinSampler; //  8
+        Uint16 BaseLevel, MaxLevel;  // 16
+        Uint8 Swizzle[4];            // 20
+        Uint8 DepthStencilMode;      // 24
         // Mirrors m_forceTextureParamsResync: the widened-channel carrier needs a swizzle
         // override that the frontend params version does not move for.
-        Uint8 ForceResync;
-        Uint8 Pad0[2];
-        Float MinLod, MaxLod, LodBias;
+        Uint8 ForceResync;           // 25
+        // Mirrors m_forceSamplerResync, which had no wire spelling at all before P4a. What it
+        // guards is not mis-filtering but an INCOMPLETE texture sampling (0,0,0,1) after a
+        // driver re-mint, which is why it is a second bit and not folded into ForceResync.
+        Uint8 SamplerResync;         // 26
+        Uint8 Pad0;                  // 27
+        Float MinLod, MaxLod, LodBias; // 28
     };
-    MGP_ASSERT_POD(MGPTextureParams, 32);
+    MGP_ASSERT_POD(MGPTextureParams, 40);
+
+    // MGPTextureParams::DepthStencilMode's two legal values, and the ONLY spelling of them
+    // (P4a, ID-12 / esprytobj DV-2). The frontend keeps a GLenum - GL_DEPTH_COMPONENT 0x1902,
+    // GL_STENCIL_INDEX 0x1901 - and a Uint8 cannot hold one, so the aspect is NUMBERED here
+    // rather than truncated there. The GLenum -> byte helper belongs to the client emitter;
+    // this header owns the two numbers, so the emitter and both backends cannot disagree.
+    //
+    // 0 IS DEPTH, AND THAT IS THE WHOLE REASON FOR THIS ORDER RATHER THAN THE ENUM'S LOW BYTE.
+    // GL_DEPTH_COMPONENT is the GL initial value of GL_DEPTH_STENCIL_TEXTURE_MODE and a
+    // texture that never asks for the stencil aspect never emits the call at all, so A ZEROED
+    // RECORD MUST DECODE TO EXACTLY WHAT AN UNTOUCHED TEXTURE ALREADY HAS. Numbering by the
+    // low byte would have made depth 0x02 and stencil 0x01 and left zero meaning nothing.
+    inline constexpr Uint8 kMGPipeDepthStencilModeDepth = 0;   // GL_DEPTH_COMPONENT
+    inline constexpr Uint8 kMGPipeDepthStencilModeStencil = 1; // GL_STENCIL_INDEX
 
     // create_shader_state. The reflection blob is the whole LinkArtifacts + SpirvArtifacts
     // archive; P0.5 extracts those types out of ProgramObject.h so a server can
@@ -338,35 +586,183 @@ namespace MobileGL::MG_Pipe {
     // set_*
     // ---------------------------------------------------------------------------------
 
+    // MGPSurface::Kind's three values (P4a, ID-12 / esprytobj DV-4). MGPipeKind is REUSED
+    // rather than a second three-value enum minted beside it: it already spells Texture and
+    // Renderbuffer, its None is 0, and a zero-initialised MGPSurface is therefore ALREADY the
+    // empty attachment point this record describes - {Res = kMGPipeNullHandle, Kind = None}
+    // and every other field zero. The static_assert is what keeps that true if MGPipeKind is
+    // ever reordered.
+    inline constexpr Uint8 kMGPipeSurfaceKindNone = static_cast<Uint8>(MGPipeKind::None);
+    inline constexpr Uint8 kMGPipeSurfaceKindTexture = static_cast<Uint8>(MGPipeKind::Texture);
+    inline constexpr Uint8 kMGPipeSurfaceKindRenderbuffer =
+        static_cast<Uint8>(MGPipeKind::Renderbuffer);
+    static_assert(kMGPipeSurfaceKindNone == 0,
+                  "a zero-initialised MGPSurface must already be the empty attachment point");
+
+    // MGPSurface::TextureTarget for a point that names no texture: the renderbuffer point and
+    // the empty point both carry it. It is MobileGL::TextureTarget::Unknown, which is -1 and
+    // therefore 0xFFFF in the field's Uint16 - a value no real target has, so a reader that
+    // forgets to gate on Kind gets a nonsense target rather than a plausible wrong one.
+    inline constexpr Uint16 kMGPipeSurfaceNoTextureTarget = 0xFFFF;
+    static_assert(kMGPipeSurfaceNoTextureTarget ==
+                      static_cast<Uint16>(MobileGL::TextureTarget::Unknown),
+                  "kMGPipeSurfaceNoTextureTarget is TextureTarget::Unknown widened to the "
+                  "field, and MG_State moved Unknown off -1");
+
     // = pipe_surface. internalFormat is INLINE so the four cross-object masks fall out at
     // push time with no lookup (section 4.5.6).
     struct MGPSurface {
         MGPipeHandle Res;
         Uint32 InternalFormat;
-        Uint8 Kind; // Texture | Renderbuffer | None
+        Uint8 Kind; // kMGPipeSurfaceKind{None,Texture,Renderbuffer}, above
         Uint8 Layered;
         Uint16 Level;
         Uint32 Layer;
-        Uint16 UploadTarget;
-        Uint16 Pad0;
+        Uint16 UploadTarget; // static_cast<Uint16>(MobileGL::TextureUploadTarget)
+        // P4a, ID-12 / esprytobj DV-5: WAS Pad0, and the size did not move - the two bytes
+        // were already here. static_cast<Uint16>(MobileGL::TextureTarget), and
+        // kMGPipeSurfaceNoTextureTarget on every point that is not a texture.
+        //
+        // THE FOUR CROSS-OBJECT MASKS ARE WHY IT EXISTS. IsSnormFallbackAttachment,
+        // IsUnormFallbackAttachment and IsAlphaWidenedColorAttachment all reduce to
+        // (format, TEXTURE TARGET) - ShouldUseCaveatTextureFormat(format, target) and
+        // BackendTextureFormatAddsAlpha(format, target) - and no TextureUploadTarget ->
+        // TextureTarget inverse exists anywhere in the tree, so UploadTarget cannot answer
+        // them. Without this field D-C1's promise that the inline InternalFormat makes the
+        // masks "fall out at push time with no lookup" is unkeepable and the backend keeps
+        // reading the frontend attachment objects.
+        //
+        // CONSULTED ONLY WHEN Kind == kMGPipeSurfaceKindTexture. A zero-initialised record
+        // carries 0, which is TextureTarget::Texture1D and not the sentinel; that is not a
+        // defect, because such a record is Kind == None and names no texture at all. Gating
+        // on Kind is the reader's contract.
+        Uint16 TextureTarget;
     };
     MGP_ASSERT_POD(MGPSurface, 24);
 
+    // P4a, D-C2/D-C3 and ID-19: THE RECORD DESCRIBES A FRAMEBUFFER OBJECT, and Target says
+    // whether it ALSO moves a binding.
+    //
+    // A `Named` record describes the framebuffer object it names (Fbo) and changes NO
+    // binding. `Draw` / `Read` / `Both` records describe the same object AND set the bound
+    // handle(s) of the target(s) they name.
+    //
+    // The applier therefore keeps records PER FRAMEBUFFER OBJECT, keyed by the handle's slot
+    // (the generation is checked on lookup and a stale one refuses; a framebuffer has no wire
+    // lifetime - D-I2, the catalogue has no framebuffer delete - so a successor's record
+    // simply OVERWRITES the slot), plus the two bound handles. And every DSA entry point that
+    // hands a framebuffer to the server BY NAME - BlitNamedFramebuffer, the four
+    // ClearNamedFramebuffer*, and the DSA attachment / draw-buffer / read-buffer setters at
+    // their validate point - is PRECEDED BY A Named RECORD, so that any framebuffer the
+    // server is about to receive by name already has one.
+    //
+    // That last rule is the phase's main correction, not a nicety. With only the two
+    // bound-target records, glClearNamedFramebufferfv(fbo) on an unbound fbo made the backend
+    // mint a fresh driver framebuffer with NO ATTACHMENTS, find no record for it, decline,
+    // and then issue the clear against it anyway - GL_INVALID_FRAMEBUFFER_OPERATION and
+    // nothing cleared, where the legacy arm cleared correctly. Writing such an object into
+    // the bound-target record instead would have been worse: the applier would then claim it
+    // is bound.
+    //
+    // GL has two independent framebuffer bindings and one record carries one Fbo, so a
+    // Draw/Read pair is two records and one object bound to both targets is one record with
+    // Both. The draw-buffer array belongs to the OBJECT the record names; it reaches the
+    // driver's bound draw framebuffer only for a record whose Target is Draw or Both -
+    // Espryt's own comment records the Minecraft 26.x OIT bug where a READ-only sync landed
+    // glDrawBuffers on the wrong framebuffer - and a Named record's draw buffers are applied
+    // when that object is next configured, never to whatever happens to be bound. ReadSurface
+    // is resolved from THAT framebuffer's own read buffer in EVERY record, Named included,
+    // which is what makes the read-buffer-shared-FBO defect class unrepresentable rather than
+    // merely fixed.
+    //
+    // Target IS A ContentHash INPUT (the hash covers the whole record), and the emitter's
+    // suppressor must be keyed by the framebuffer the record names, not by one global slot:
+    // two different objects' Named records in a row must both go out, and a Named record must
+    // never be suppressed against the same object's bound record or the reverse.
+    enum class MGPipeFramebufferTarget : Uint8 {
+        Draw = 0,
+        Read = 1,
+        Both = 2,
+        // Describes the framebuffer named by Fbo and changes no binding (ID-19). Emitted
+        // ahead of every DSA entry point that hands that framebuffer over by name.
+        Named = 3,
+        Count,
+    };
+
+    // MGPFramebufferState::Color[] and DrawBuffers[] are ONE array width, and it is the wire's
+    // bound rather than the driver's: GetDynamicParameters().MaxColorAttachments is the raw ES
+    // cap and is not clamped to 8 on the GLES path, so a driver reporting more would silently
+    // truncate this record. The framebuffer subsystem bit is REFUSED at its first lookup in
+    // that case, with one ERROR naming the cap, and the legacy arm runs - the same shape the
+    // backend's existing bit-8-requires-bit-7 refusal already ships
+    // (ResolveFramebufferSubsystemArm, beside ResolveResourceSubsystemArm). Widening the
+    // payload is a wire change nobody has evidence for, and truncating silently is the bug
+    // class this phase is closing.
+    inline constexpr Uint32 kMGPipeMaxColorAttachments = 8;
+    static_assert(kMGPipeMaxColorAttachments == MobileGL::kMGMaxDrawBuffers,
+                  "MGPFramebufferState::Color[] and DrawBuffers[] are one array width");
+
+    // ONE RECORD DESCRIBES ONE FRAMEBUFFER OBJECT - the one named by Fbo - and Target says
+    // whether it also moves a binding (P4a, D-C2 as corrected by ID-19; see
+    // MGPipeFramebufferTarget above for the failure that forced it).
+    //
+    // A Named record describes that object and changes NO binding. Draw / Read / Both records
+    // describe that object AND set the bound handle(s) of the target(s) they name. The applier
+    // keeps these records PER FRAMEBUFFER OBJECT, keyed by Fbo's slot (generation checked on
+    // lookup; a framebuffer has no wire lifetime - D-I2 - so a successor's record simply
+    // overwrites the slot), plus the two bound handles; every DSA entry point that hands a
+    // framebuffer to the server by name is preceded by a Named record.
+    //
+    // WHAT Target CHANGES, FIELD BY FIELD. NO FIELD IN THIS RECORD REFERS TO "the currently
+    // bound framebuffer" - every one of them describes the object named by Fbo - and that is
+    // the invariant a reader depends on:
+    //
+    //   Fbo, Color[], Depth, Stencil, ReadSurface, Width/Height/Layers/Samples,
+    //   FixedSampleLocations, IsDefault, Complete
+    //       properties of the object named by Fbo, identical in meaning under every Target.
+    //       In particular ReadSurface is resolved from THAT framebuffer's own read buffer -
+    //       on a Named record too - never from whichever framebuffer is bound to GL_READ.
+    //   DrawBuffers[]
+    //       a property of the named object; it reaches the driver's bound draw framebuffer
+    //       only when Target is Draw or Both. Under Named it is stored with the object and
+    //       applied when that object is next configured.
+    //   Target
+    //       the only binding-specific field: Draw/Read/Both name the binding(s) this record
+    //       also sets, Named names none. It is a ContentHash input.
+    //   ContentHash
+    //       per RECORD, not per object, and the emitter's suppressor is keyed by the
+    //       framebuffer named: a Named record must never be suppressed against the same
+    //       object's bound record, nor one object's Named record against another's.
     struct MGPFramebufferState {
         MGPipeHandle Fbo; // kMGPipeDefaultFramebuffer for the default framebuffer
         MGPSurface Color[8];
         MGPSurface Depth, Stencil;
-        // The RESOLVED read surface, not an index. This is what structurally closes the
+        // The RESOLVED read surface, not an index, and it is THIS framebuffer's own read
+        // buffer under every Target - Named included. This is what structurally closes the
         // read-buffer-shared-FBO defect class.
         MGPSurface ReadSurface;
-        Int8 DrawBuffers[8]; // attachment index, -1 = NONE
+        // attachment index, -1 = NONE. The named object's array; applied to the bound draw
+        // framebuffer only when Target is Draw or Both.
+        Int8 DrawBuffers[8];
         Uint16 Width, Height, Layers, Samples;
-        Uint8 FixedSampleLocations, IsDefault, Complete, Pad0;
+        // Complete is FramebufferObject::CheckCompleteness(), the frontend-only answer - NOT
+        // glCheckFramebufferStatus's. CheckFramebufferStatus_State additionally consults
+        // ActiveBackendRejectsDistinctDepthStencil() and HasNonRenderableColorAttachment,
+        // which read the backend's probed format-capability cache; a client emitting that
+        // answer would be reading the backend from the client side, which is the exact
+        // coupling this boundary exists to remove. A later phase must not assume the stronger
+        // answer, and glCheckFramebufferStatus keeps answering from the frontend as it does
+        // today.
+        Uint8 FixedSampleLocations, IsDefault, Complete;
+        // MGPipeFramebufferTarget, above (P4a, D-C2; was Pad0). Draw/Read/Both also set the
+        // named binding(s); Named sets none (ID-19). The ONLY binding-specific field.
+        Uint8 Target;
         Uint32 Pad1;
         // Two jobs (section 4.5.6): the server's render-pass memo key, and the CLIENT's
         // emission suppressor - an unchanged hash means this record is not sent at all.
         // The same pattern is mandatory for every kVarTail set_* below, or 26.2's
         // redundant glBindSampler traffic reappears as a variable-length record per batch.
+        // Target is one of its inputs, and the suppressor is keyed per framebuffer.
         Uint64 ContentHash;
     };
     MGP_ASSERT_POD(MGPFramebufferState, 304);
@@ -378,6 +774,20 @@ namespace MobileGL::MG_Pipe {
     // static_assert, because this header may not include a frontend one.
     inline constexpr Uint32 kMGPipeMaxVertexAttribs = 32;
 
+    // P4a, D-G2. MobileGL's texture-unit space is ONE MERGED array of
+    // TextureState::MAX_TEXTURE_IMAGE_UNITS = 192 - there is no stage dimension on
+    // set_sampler_views / bind_sampler_states / set_shader_images, because the same unit may
+    // be sampled from two stages and per-stage 32 is an advertised number rather than a
+    // storage shape. These two bound the three var-tail sets' Start + Count, and a record
+    // that names a window outside them is Fatal{ProtocolCorruption} - the var-tail window IS
+    // the bound and entries outside it are not cleared.
+    //
+    // Pinned against the frontend constant in MG_Impl/Pipe/PipeFill.cpp, the one translation
+    // unit that sees both, exactly as kMGPipeMaxVertexAttribs is: this header may not include
+    // a frontend one.
+    inline constexpr Uint32 kMGPipeMaxTextureUnits = 192;
+    inline constexpr Uint32 kMGPipeMaxImageUnits = 192;
+
     struct MGPVertexBuffer {
         MGPipeHandle Res;
         Uint64 Offset;
@@ -617,6 +1027,30 @@ namespace MobileGL::MG_Pipe {
     // decision belongs on the side that pays the GPU cost. Mali prices texture upload by
     // JOB COUNT: ~100 sprite rects against one union box measured +6 ms/frame.
     //
+    // `Target` IS TWO FACTS IN ONE Uint16 (P4a, D-D3 / ID-12), and MGPipePackSubDataTarget
+    // under the struct is the only spelling of the encoding - nothing may open-code a half:
+    //
+    //   low byte  = MGPipeResourceTarget          - WHICH KIND of storage the destination is.
+    //                                               The applier branches on it: a buffer
+    //                                               target dispatches into MGPipeResourceOps,
+    //                                               every other target accumulates a pending
+    //                                               upload for the texture sync to consume.
+    //   high byte = MobileGL::TextureUploadTarget - WHICH cube face / upload target the level
+    //                                               belongs to. It is NOT derivable from the
+    //                                               resource target - six faces share TexCube
+    //                                               - and 26 enumerators leave a byte ample.
+    //
+    // WHY THAT WAY ROUND, AND WHY THE ENCODING LIVES HERE RATHER THAN IN EACH EMITTER. The
+    // applier's SubDataNamesABuffer tests the WHOLE field == 0, and
+    // TextureUploadTarget::Texture1D is 0 - so a texture record carrying the bare upload
+    // enumerator is indistinguishable from a buffer record exactly when its owner is a 1D
+    // texture, and that texture's upload is dispatched into the buffer path. With the
+    // resource target in the LOW byte a buffer record's Target stays EXACTLY
+    // kMGPipeResourceTargetBuffer - P3a's buffer records are unchanged on the wire, their
+    // upload byte being zero too - while a texture record can never be zero, because no
+    // texture's MGPipeResourceTarget is. The static_assert under the struct holds that
+    // invariant, and the applier's whole-field test stays right either way.
+    //
     // THE BUFFER HALF. With Target == Buffer there is no level and no box, so the destination
     // byte range rides in the box's first coordinate and first extent: UnionBox.X is the byte
     // offset, UnionBox.W the byte size, Y = Z = 0, H = D = 1, Level = 0, RegionCount = 0.
@@ -635,6 +1069,8 @@ namespace MobileGL::MG_Pipe {
     // the only spelling of this convention; nothing else reads the box for a buffer.
     struct MGPSubData {
         MGPipeHandle Res;
+        // Target is PACKED - see the block above, and read it only through
+        // MGPipeSubDataResourceTargetOf / MGPipeSubDataUploadTargetOf below.
         Uint16 Target, Level;
         // Replaces the backend's `uploadData == mipData` pointer comparison: are these
         // bytes an untransformed level shadow?
@@ -647,6 +1083,38 @@ namespace MobileGL::MG_Pipe {
     };
     MGP_ASSERT_POD(MGPSubData, 72);
 
+    // The one spelling of MGPSubData::Target's encoding, stated above the struct.
+    //
+    // Uint32 ARGUMENTS RATHER THAN THE TWO ENUM TYPES, and that is deliberate. This header is
+    // the contract: MGPipeResourceTarget is minted in it, but the upload half is MG_State's
+    // TextureUploadTarget, and nobody who reads the packed field ever needs that type - the
+    // applier and both backends read the halves BACK, as bytes, through the two accessors.
+    // Naming it in a signature would pin the contract's own API to a frontend enum for no
+    // reader's benefit, and would stop kMGPipeResourceTargetBuffer being passed as it stands.
+    // Callers pass static_cast<Uint32>(MobileGL::TextureUploadTarget) for `uploadTarget` and
+    // static_cast<Uint32>(MGPipeResourceTarget) - or kMGPipeResourceTargetBuffer - for
+    // `resourceTarget`.
+    constexpr inline Uint16 MGPipePackSubDataTarget(Uint32 resourceTarget, Uint32 uploadTarget) {
+        return static_cast<Uint16>((resourceTarget & 0xFFu) | ((uploadTarget & 0xFFu) << 8));
+    }
+    // Comparable against static_cast<Uint8>(MGPipeResourceTarget) / kMGPipeResourceTargetBuffer.
+    constexpr inline Uint8 MGPipeSubDataResourceTargetOf(Uint16 packed) {
+        return static_cast<Uint8>(packed & 0xFFu);
+    }
+    // Comparable against static_cast<Uint8>(MobileGL::TextureUploadTarget).
+    constexpr inline Uint8 MGPipeSubDataUploadTargetOf(Uint16 packed) {
+        return static_cast<Uint8>((packed >> 8) & 0xFFu);
+    }
+    // THE INVARIANT P3a's records and the applier's buffer test both rest on: a buffer
+    // record's Target is exactly kMGPipeResourceTargetBuffer, whole field, upload byte and
+    // all. TextureUploadTarget::Texture1D is 0, so the buffer case is the one place where the
+    // packed form and a bare enumerator agree - and it has to stay that place.
+    static_assert(MGPipePackSubDataTarget(kMGPipeResourceTargetBuffer, 0u) ==
+                      kMGPipeResourceTargetBuffer,
+                  "a buffer sub-data record's Target must stay exactly "
+                  "kMGPipeResourceTargetBuffer: the applier's SubDataNamesABuffer tests the "
+                  "whole field == 0");
+
     // Encodes a buffer byte range into the record's box. False, with the record untouched,
     // when the range does not fit one record: the emitter has to split it.
     inline Bool MGPipeSetSubDataBufferRange(MGPSubData& record, Uint64 offset, Uint64 size) {
@@ -675,12 +1143,66 @@ namespace MobileGL::MG_Pipe {
     // is ((void)0) - the applier is one function call away - and the transport wires the
     // doorbell to this predicate when it lands.
     //
-    // Immutable is exactly the right discriminator: it is set iff the store came from a
-    // glBufferStorage* entry point, which is the definition of the allowed case.
+    // P4a, D-A2: THE PREDICATE IS NARROWED TO NAME THE BUFFER TARGET, and that is a
+    // requirement rather than a tidy-up. glTexStorage* also sets Immutable - it is a real
+    // descriptor fact the backend reads, and the client must set it - but texture allocation
+    // is already deferred to sync time in monolith (glTexImage*/glTexStorage* only
+    // MarkStorageDirty; even glRenderbufferStorage* allocates lazily inside SyncToBackend), so
+    // splitting changes no observable behaviour and this batch must NOT ack. glBufferStorage
+    // stays the only entry point allowed a synchronous acknowledgement.
+    //
+    // PipeCatalogueTest.ResourceRespecifyAcksOnlyImmutableStorage drives glTexStorage2D and
+    // glRenderbufferStorage idioms through it, and is the negative control for a future
+    // widening.
     inline Bool MGPipeResourceRespecifyNeedsAck(const MGPResourceDesc& desc) {
-        return desc.Immutable != 0;
+        return desc.Immutable != 0 && desc.Target == kMGPipeResourceTargetBuffer;
     }
 
+    // P4a, ID-18 M4: A RESPECIFY WHOSE STORAGE-DEFINING FIELDS ALL EQUAL THE STORED
+    // DESCRIPTOR IS A METADATA UPDATE, NOT A REALLOCATION.
+    //
+    // MGPResourceDesc::BindMask and ImageBindableHint are STICKY facts the client discovers
+    // AFTER allocation - a texture first bound as a shader image, first used as a render
+    // target - and they ride resource_create and every resource_respecify. An IMMUTABLE
+    // texture never has a later respecify, so without a rule those two would reach the server
+    // only by accident, or never; with one, a mask change after allocation emits a
+    // resource_respecify that REPEATS the storage the resource already has.
+    //
+    // The applier and both twins must classify such a record as a metadata update:
+    //   - NO reallocation acknowledgement. MGPipeResourceRespecifyNeedsAck above still
+    //     answers the per-record question, but a metadata update allocates nothing, so a
+    //     record it classifies as metadata is not acked even when that predicate says the
+    //     call may require one.
+    //   - NO PendingUploads clear when the call names NO level. This REFINES the whole-resource
+    //     clear: identical storage fields with a null MGPRespecifiedLevel clear NOTHING. (The
+    //     level-scoped rule exists because clearing the whole vector on a level-1 definition
+    //     silently dropped level 0's accepted texels; a metadata update must drop neither.) A
+    //     call that NAMES a level is that level's redefinition whatever the descriptor says -
+    //     a non-base level's extent is not a descriptor field - and drops exactly that level
+    //     (P4a final review C-1); the client's mask republish passes null on purpose.
+    //   - The stored descriptor's BindMask and ImageBindableHint ARE updated: the applier
+    //     replaces the descriptor WHOLE with the one the client sent (PipeApply.cpp), and the
+    //     mask in it is the CLIENT's sticky OR (TextureEmit.h's entry, never cleared), so the
+    //     replacement can never lose a bit the record once carried. The twin re-derives its
+    //     storage flags from the new mask on its next sync, recreating backend storage only
+    //     where the backend actually needs it. The record itself is not a request to recreate.
+    //
+    // THE STORAGE-DEFINING FIELD SET, named here so that neither side has to guess and a
+    // later field cannot join it by silence. It is every MGPResourceDesc member except the
+    // three metadata ones and the padding:
+    //
+    //     Target, StorageKind, InternalFormat, Width, Height, Depth, ArrayLayers, Levels,
+    //     Samples, FixedSampleLocations, Immutable, Usage, StorageFlags, HasDefinedContent,
+    //     ViewOf, BufferForTexBuffer, BufOffset, BufSize.
+    //
+    // `Resource` is the identity the stored descriptor is looked up BY, not a comparand. The
+    // three fields that may differ on a metadata update are exactly BindMask,
+    // ImageBindableHint and GlNameForDiag (diagnostics only, never an identity, never a memo
+    // key). HasDefinedContent is storage-defining ON PURPOSE: glBufferData(size, NULL) at an
+    // unchanged size is an orphaning reallocation and has to keep clearing, rather than being
+    // mistaken for a mask change. A field added to MGPResourceDesc must be placed in one of
+    // the two lists in the same commit - PipeCatalogue pins the struct's size for that.
+
     // The forward terminator for a server-initiated texture pull (section 7.1). May carry
     // zero regions - that is how a pull that needs nothing is answered.
     struct MGPSubDataComplete {

MobileGL/MG_Pipe/PipeApply.h

@@ -28,6 +28,17 @@
 // (MG_Impl/Pipe) already have it, and MG_Pipe sits below MG_Backend.
 //
 // Compiled only under MOBILEGL_PIPE_PUSH (CMakeLists.txt), so the pull build gains no symbol.
+// P4a: create_shader_state carries the reflection ARCHIVE, and in monolith the archive does
+// not travel - the two structs ride beside the record through the entry point's companion
+// pointers, exactly as P3a's `const void* initialBytes` does (D-H3, the one Blob rule). So
+// this header needs their NAMES and never their definitions; the forward declaration is the
+// whole coupling and the closure gate is what keeps it one. The verify build is the only
+// place the codec runs, and it runs from PipeApply.cpp.
+namespace MobileGL::MG_State::GLState {
+    struct LinkArtifacts;
+    struct SpirvArtifacts;
+} // namespace MobileGL::MG_State::GLState
+
 namespace MobileGL::MG_Pipe {
     struct PipeInputs;
 
@@ -109,8 +120,91 @@ namespace MobileGL::MG_Pipe {
     // own dense high-water mark and no further, so the bound costs nothing until a record is
     // already corrupt. Package C bounds handle.Slot the same way before
     // BackendSlotTable::EntryAt, which resizes on a client-supplied index too.
+    // P4a: THE BOUND IS PER KIND, not per table, and that is what keeps one number honest
+    // while the number of tables grows. The slot spaces of kinds Buffer, Texture and
+    // Renderbuffer are INDEPENDENT (MGPipeSlotAllocator allocates per kind), so three
+    // different objects can hold slot 7; the applier therefore keeps one Vector per resource
+    // KIND and indexes it by slot, rather than one Vector indexed by slot alone. Each is
+    // bounded by kMGPipeMaxResourceSlots and each grows only to its own dense high-water mark.
     inline constexpr Uint32 kMGPipeMaxResourceSlots = 1u << 20;
     inline constexpr Uint32 kMGPipeMaxVertexElementsSlots = 1u << 16;
+    // P4a's three, and the argument is written out for each because the records differ in
+    // size. None is ever allocated by being named: the tables grow to the client's own dense
+    // high-water mark and no further, so the bound costs nothing until a record is corrupt.
+    //
+    // A sampler CSO record is a 100-byte value plus a handle, and sampler CSOs are
+    // CONTENT-ADDRESSED at capacity 256 on the client, so the live population is bounded by
+    // that cache and not by the application. 1<<16 is far above anything a GL program can hold
+    // and small enough that a corrupt slot is refused rather than allocated.
+    inline constexpr Uint32 kMGPipeMaxSamplerCsoSlots = 1u << 16;
+    // A sampler VIEW is identity-addressed one per ITextureObject (P4a D-F2), so its
+    // population tracks the texture population exactly and it takes the texture bound.
+    inline constexpr Uint32 kMGPipeMaxSamplerViewSlots = 1u << 20;
+    // The shader-CSO bound is the SLOT LIMIT ITSELF, because the composite band lives inside
+    // that space (MGPipeHandles.h): a bound below it would refuse the very slots
+    // AllocateComposite is allowed to hand out.
+    inline constexpr Uint32 kMGPipeMaxShaderCsoSlots = kMGPipeShaderCsoSlotLimit;
+    static_assert(kMGPipeMaxShaderCsoSlots > kMGPipeShaderCsoCompositeSlotBase,
+                  "the ShaderCso bound must contain the composite band, or a composite handle "
+                  "is refused as out of range on arrival");
+    // ID-19(b): the framebuffer record is now PER OBJECT and its table is slot-indexed like the
+    // five above, so it takes a bound on the same terms. A framebuffer record is 304 bytes and
+    // an FBO is a CONTAINER object - not shared between contexts, minted a few dozen at a time
+    // by a renderer and a few hundred by a shader pack - so 1<<16 is orders of magnitude above
+    // any live population and still turns a corrupt Uint32 into a refusal rather than a
+    // 4-billion-entry resize.
+    inline constexpr Uint32 kMGPipeMaxFramebufferSlots = 1u << 16;
+
+    // THE FOURTH set_framebuffer_state TARGET is the contract's MGPipeFramebufferTarget::Named (c0e):
+    // "this record describes the framebuffer it names; no binding changes." Draw / Read / Both
+    // write the record AND set the bound handle(s); Named writes the record only, which is how
+    // the DSA entry points - BlitNamedFramebuffer and the four ClearNamedFramebuffer* - hand the
+    // server a record for a framebuffer bound to neither binding (esprytobj review C-1, ID-19).
+
+    // The two framebuffer BINDINGS, and there are two rather than three: Both and Named are
+    // things a RECORD says, not bindings a server has. MGPipeApplierState::BoundFramebuffer is
+    // indexed by MGPipeFramebufferTarget::Draw / ::Read, which is what makes package D's
+    // "is this framebuffer the one bound to target t" one array compare (ID-19(d)).
+    inline constexpr Uint32 kMGPipeFramebufferBindingCount = 2;
+    static_assert(static_cast<Uint8>(MGPipeFramebufferTarget::Draw) == 0 &&
+                      static_cast<Uint8>(MGPipeFramebufferTarget::Read) == 1,
+                  "BoundFramebuffer is indexed by the target byte; Draw and Read must be 0 and 1");
+
+    // ---- P4a's SHAPE bounds, and they are the same argument the slot bounds above make, one
+    // level down: every number below arrives inside a payload, every one of them decides how
+    // much the applier allocates or how far it indexes, and NONE of them is ever allocated by
+    // being named. A record that names one past its bound is Fatal{ProtocolCorruption} - the
+    // verdict this file reserves for a record that would make the server act outside its own
+    // storage - and never a resize.
+
+    // A sub-data record's mip level. GL's own bound is log2 of the maximum texture size, which
+    // no device reports above 2^16, so a level index of 32 addresses a texture no
+    // implementation can allocate and is a corrupt record rather than a large one. It is NOT
+    // MGPTextureParams::MaxLevel's bound: GL_TEXTURE_MAX_LEVEL defaults to 1000 and is a
+    // parameter, not a storage level, so nothing here polices it.
+    inline constexpr Uint16 kMGPipeMaxTextureLevels = 32;
+
+    // The pending-upload set (below) is keyed by (UploadTarget, Level) and both halves come
+    // off the wire. Levels are bounded above; upload targets are not - a cube face, an array
+    // target and a rectangle target are all legal values - so the number of DISTINCT keys one
+    // resource may accumulate is bounded here. Six cube faces times 32 levels is 192; 256
+    // leaves room for a target space this phase has not enumerated and still refuses the
+    // unbounded growth a corrupt Uint16 would otherwise buy.
+    inline constexpr Uint32 kMGPipeMaxPendingUploads = 256;
+
+    // The rect list behind one pending entry. The frontend keeps at most MipmapStorage's
+    // kMaxDirtyRects = 96 per level and answers "0 rects" for everything it cannot describe
+    // that way, which is the model this mirrors: an accumulation that would exceed this
+    // collapses to BOX ONLY - the same answer, with the same meaning, and never a dropped
+    // region. 256 is that bound with room for several emissions accumulating behind a bail.
+    inline constexpr Uint32 kMGPipeMaxPendingUploadRegions = 256;
+
+    // The default uniform block's image, the one allocation P4a adds per program. The size
+    // comes from the program's own MGPProgramDesc::GlobalUboSize, so it is checked ONCE at
+    // create_shader_state and the set_global_constants that follows can only allocate what the
+    // create already declared. 16 MiB is four orders of magnitude above any default uniform
+    // block a real program links and still turns a corrupt Uint32 into a refusal.
+    inline constexpr Uint32 kMGPipeMaxGlobalConstantsBytes = 16u << 20;
 
     // One record per live resource, indexed by MGPipeHandle::Slot, kind Buffer; slot 0 is the
     // reserved null handle and is never live.
@@ -129,6 +223,126 @@ namespace MobileGL::MG_Pipe {
         // persistent-mapped host writes can set it with zero new record kinds; a verify build
         // pins that it is false, so that phase cannot land a silent semantic change under it.
         Bool HasLiveHostWrites = false;
+
+        // ---- P4a. Only a record of kind Texture ever carries these; a buffer's stay at
+        // their defaults, which is what keeps ONE record type for the discriminated
+        // descriptor rather than a second one that would have to be kept in step with it.
+
+        // set_texture_params, per texture OBJECT and independent of any binding - which is
+        // the whole point of addressing it by resource: a texture that is only an FBO
+        // attachment, only an image-unit binding or only a glCopyImageSubData endpoint has no
+        // sampler view to hang its parameters on, and today the READ-attachment case reaches
+        // no parameter push at all. ParamsSerial replaces the twin's
+        // m_syncedTextureParamsVersion + m_forceTextureParamsResync pair.
+        //
+        // Params.BuiltinSampler MAY NAME A CSO WHOSE RECORD IS GONE. set_texture_params
+        // deliberately does not resolve it (the sampler CSO is content-addressed and shared,
+        // D-F1, and the ordering between the two families is the emitter's), and
+        // delete_sampler_state does not sweep the textures that name the CSO it drops. So a
+        // consumer that follows this handle must expect SamplerCsos[slot] to be dead or
+        // recycled and treat that as it treats any other stale handle - it is an ordering fact
+        // about the two emitters, not a corrupt record.
+        MGPTextureParams Params{};
+        Uint64 ParamsSerial = 0;
+        // The SamplerViewCso minted for this texture (P4a D-F2: one per ITextureObject,
+        // re-issued on the same handle whenever the restrictions move).
+        MGPipeHandle ViewCso = kMGPipeNullHandle;
+        // THE PENDING-UPLOAD SET, and it is server-side state on purpose (D-D5). The client
+        // clears its own dirty flags at EMISSION, for the levels whose record the applier
+        // accepted; Espryt's upload loop has bail arms - an incomplete texture returns early,
+        // a multisample target refreshes and skips - that today leave the frontend flag set,
+        // so a naive move of the clear to the client would lose those texels. The applier
+        // accumulates the emitted shape here instead, it survives any number of bails, and
+        // Espryt consumes and clears an entry only where it actually uploads.
+        //
+        // The verify lane's RETAIN MODE is what gates the shape: a consume-and-clear set
+        // cannot be recomputed after emission, so the tracker retains the pre-clear set and
+        // the comparator compares the emitted (UnionBox, RegionCount, Regions[]) against it
+        // field by field.
+        //
+        // THE SET IS KEYED (UploadTarget, Level) AND EVERY KEY IS INDEPENDENT OF EVERY OTHER.
+        // That is not a detail: a respecify redefines ONE level when it arrives from
+        // glTexImage*D (MGPipeApplyResourceRespecify's trailing MGPRespecifiedLevel*), so it
+        // may only drop that one key - the frontend's AllocateStorage / MarkStorageDirty are
+        // per (uploadTarget, level) too, and the other levels' dirty flags were cleared at
+        // THEIR emission, so nothing anywhere still owes them.
+        //
+        // THE ACCUMULATED RECT LIST MAY OVERLAP, AND A CONSUMER MUST TOLERATE THAT. Behind one
+        // level the frontend's own model is pairwise disjoint (MipmapStorage keeps it so), but
+        // this list CONCATENATES the lists of successive emissions and the applier's gate only
+        // asks that each rect be inside the record's own union box - so two emissions that
+        // touch the same texels leave two rects that do. Staging N rects therefore uploads
+        // those texels twice, which is a cost and never a correctness problem; nothing here
+        // de-duplicates and nothing downstream may assume "the frontend's model" means disjoint
+        // once the shapes have been accumulated.
+        struct PendingUpload {
+            Uint16 UploadTarget = 0;
+            Uint16 Level = 0;
+            MGPBox UnionBox{};
+            Vector<MGPSubRegion> Regions;
+        };
+        Vector<PendingUpload> PendingUploads;
+    };
+
+    // ---------------------------------------------------------------------------------
+    // P4a: the three new object-record kinds (D-J1)
+    // ---------------------------------------------------------------------------------
+    //
+    // All three follow MGPipeResourceRecord's shape exactly - Gen, Live, a payload and a
+    // server-owned monotone Serial - because the body-level idioms are the same ones:
+    // a create starts the record OVER rather than editing it (a recycled slot's record must
+    // not contribute one field, and Serial stays 0 because a create is not a mutation, so a
+    // fresh backend twin starting at 0 agrees without either side publishing anything); the
+    // serial moves BEFORE the backend is told; a destroy drops the record whole and keeps the
+    // generation, and the CLIENT frees the slot afterwards.
+
+    // create_sampler_state / delete_sampler_state. The parameters cross byte for byte
+    // INCLUDING borderColorForm - all three border representations are always numerically
+    // populated, so the value alone cannot say which driver entry point to use - and
+    // MOBILEGL_PIPE_VERIFY compares them FIELD BY FIELD (PipeFields.def's
+    // MGP_FIELDS_SamplerParameters), because the struct has three bytes of trailing padding
+    // and a byte comparison of it is a coin flip rather than a gate.
+    struct MGPipeSamplerCsoRecord {
+        Uint32 Gen = 0;
+        Bool Live = false;
+        SamplerParameters Params{};
+        Uint64 Serial = 0;
+    };
+
+    // create_sampler_view / delete_sampler_view: ONLY the view restrictions. Everything a
+    // glTexParameter writes lives on set_texture_params instead. Re-issuing on the same
+    // handle is how a restriction change travels (Gen moves only on slot reuse); it bumps
+    // Serial and does not rebind anything.
+    struct MGPipeSamplerViewRecord {
+        Uint32 Gen = 0;
+        Bool Live = false;
+        MGPSamplerView View{};
+        Uint64 Serial = 0;
+    };
+
+    // create/bind/delete_shader_state, plus set_global_constants' per-program half.
+    //
+    // THE ARTEFACTS ARE NOT HELD HERE IN MONOLITH: MGPProgramDesc's seven MGPBlobRefs are all
+    // declared with Size 0 ("this record does not declare its blob") and the LinkArtifacts /
+    // SpirvArtifacts ride beside the record through the entry point's companion pointers, so
+    // the applier stores the DESCRIPTOR and the identity and the server reads the frontend's
+    // own archive. That is what keeps the codec off the monolith hot path entirely; the verify
+    // build is where it is exercised, by serialising, deserialising and field-comparing before
+    // storing.
+    //
+    // GlobalConstants is the one allocation P4a adds per program, it is bounded by
+    // Desc.GlobalUboSize, and it is NOT on the hot path: set_global_constants is
+    // (ShaderCso, Version) keyed and fires at most once per program per frame.
+    struct MGPipeShaderCsoRecord {
+        Uint32 Gen = 0;
+        Bool Live = false;
+        MGPProgramDesc Desc{};
+        // GetUBOContentVersion() as last received. ~0u is the backends' "never uploaded"
+        // sentinel and the client must never emit it, so it is also what this starts at.
+        Uint32 GlobalConstantsVersion = ~Uint32{0};
+        Vector<Uint8> GlobalConstants;
+        Uint64 GlobalConstantsSerial = 0;
+        Uint64 Serial = 0;
     };
 
     // The vertex-elements CSO as the applier holds it: the unpacked blob, both views, plus
@@ -151,6 +365,27 @@ namespace MobileGL::MG_Pipe {
         Uint64 ContentSerial = 0;
     };
 
+    // set_framebuffer_state's record, HELD PER FRAMEBUFFER OBJECT and indexed by the handle's
+    // slot (ID-19(b)). It is the one record kind in this file whose object has NO WIRE LIFETIME:
+    // the catalogue has no framebuffer create and no framebuffer destroy, because a framebuffer
+    // is state and set_framebuffer_state is the only call that names one (D-I2). So there is
+    // nothing to mark dead and nothing to refuse against, and a slot is simply OVERWRITTEN by
+    // its successor's record - which is correct rather than merely tolerable, since the record
+    // that reaches this table is the description of whatever object holds the slot NOW.
+    //
+    // `Live` is therefore NOT a lifetime. It means "a record has been written at this slot",
+    // which is the only question a reader can ask: it separates a table entry that exists
+    // because the vector grew past it from one an emission actually wrote. The GENERATION is
+    // still checked on every lookup (P3a contract-review M2), and a mismatch is a LOUD refusal -
+    // it means an emitter handed a stale handle, or minted a successor without describing it,
+    // which is exactly the seam defect the DSA arm would otherwise turn into a blit into a
+    // driver framebuffer with no attachments.
+    struct MGPipeFramebufferRecord {
+        Uint32 Gen = 0;
+        Bool Live = false;
+        MGPFramebufferState State{};
+    };
+
     struct MGPipeApplierState {
         // Indexed by slot; slot 0 is the reserved null handle and is never live
         // (MGPipeHandles.h kMGPipeFirstAllocatableSlot).
@@ -217,6 +452,43 @@ namespace MobileGL::MG_Pipe {
         Vector<MGPipeResourceRecord> Resources;
         Vector<MGPipeVertexElementsRecord> VertexElementsCsos;
 
+        // ---- P4a's object records. FIVE MORE TABLES, and the two resource ones are separate
+        // Vectors rather than more rows of `Resources` above because the slot space is PER
+        // KIND: a Buffer, a Texture and a Renderbuffer can all hold slot 7 at once, so a
+        // single slot-indexed table would alias three different objects onto one record. The
+        // record TYPE is shared - one discriminated descriptor for buffers, every texture
+        // target and renderbuffers - and the bound is shared; only the table is per kind.
+        //
+        // Like the two above they are share-group state: MGPipeApplierReset does not touch
+        // them, and only the object's own death signal and MGPipeApplierReleaseObjectRecords
+        // clear them.
+        Vector<MGPipeResourceRecord> TextureResources;
+        Vector<MGPipeResourceRecord> RenderbufferResources;
+        Vector<MGPipeSamplerCsoRecord> SamplerCsos;
+        Vector<MGPipeSamplerViewRecord> SamplerViewCsos;
+        Vector<MGPipeShaderCsoRecord> ShaderCsos;
+        // The ShaderCso COMPOSITE band's records, indexed by (slot - the band's base), for the
+        // same reason MGPipeSlotAllocator keeps the band in a table of its own: the band
+        // starts at 983040, so one program-pipeline composite in the slot-indexed vector above
+        // would grow it to ~983k records of ~240 bytes each. THE SERVER STILL NEVER LEARNS IT
+        // IS A COMPOSITE - the split is an indexing detail on this side of the wire, the
+        // handle is an ordinary ShaderCso handle, and create/bind/delete_shader_state name it
+        // exactly as they name any other program.
+        Vector<MGPipeShaderCsoRecord> CompositeShaderCsos;
+        // AND THE SIXTH, WHICH IS THE ONE ID-19 ADDED. Keyed by the FRAMEBUFFER HANDLE's slot,
+        // for the reason MGPipeFramebufferRecord states: the two bound-target records the phase
+        // started with could not describe a framebuffer that is bound to neither binding, and
+        // the five DSA entry points (BlitNamedFramebuffer, the four ClearNamedFramebuffer*) hand
+        // Espryt exactly that.
+        //
+        // IT IS AN OBJECT TABLE AND IT LIVES WHERE THE OTHER OBJECT TABLES LIVE, which is also
+        // its make-current rule: MGPipeApplierReset does NOT clear it. An FBO is not shared
+        // between contexts, but its record is addressed by a slot out of one global allocator,
+        // so nothing aliases across a switch - and dropping the table would leave a
+        // DSA-only framebuffer with no record and no event that would ever re-emit one (the
+        // client's suppressor invalidation re-emits the two BOUND records and nothing else).
+        Vector<MGPipeFramebufferRecord> FramebufferRecords;
+
         // Every call this applier REFUSED because it named a record this applier does not
         // have: an unknown slot, a slot that is not live, or a generation that has moved on
         // under it. The refusal is a defined no-op - nothing stored, nothing dispatched, no
@@ -227,6 +499,58 @@ namespace MobileGL::MG_Pipe {
         // build. Per context, like the four render-state wire counters above.
         Uint64 RefusedResourceCalls = 0;
         Uint64 RefusedVertexInputCalls = 0;
+        // P4a's, in the same shape and for the same reason: every sampler, sampler-view,
+        // program and texture-params call this applier refused because it named a record this
+        // applier does not have. One counter rather than four, because the families share one
+        // legal refusal sequence (teardown -> MGPipeApplierReleaseObjectRecords -> ~Object ->
+        // death notices naming records already dropped) and an operator reading a log wants to
+        // know that ANY object call was dropped; the log line names the call and the handle.
+        //
+        // set_framebuffer_state IS DELIBERATELY NOT ON THAT LIST AND CANNOT BE. D-I2 gives a
+        // framebuffer a handle and NO wire lifetime, so the call resolves no record - there is
+        // nothing to look up, nothing to find missing and therefore nothing to refuse - and
+        // MGPSurface::Res is likewise left unresolved on purpose (D-I3: the keep-alives are the
+        // frontend's SharedPtrs and enforcing them is a later phase's). Its only verdict is
+        // Fatal{ProtocolCorruption} on a malformed record, and this counter must stay at 0
+        // across every framebuffer call in every build. ID-19(b) does not change that: the
+        // per-object table is WRITTEN by that call and never looked up by it, and the refusal
+        // that the table CAN produce - a lookup whose generation has moved on - happens on the
+        // server's own read path and is counted apart, in StaleFramebufferRecordLookups.
+        //
+        // THE OTHER CLASS IS NOT COUNTED HERE AND MUST NOT BE: a var-tail window outside its
+        // bound, or a set_texture_params whose BuiltinSampler is the null handle, would make
+        // the backend act outside its own storage or sample an object that does not exist -
+        // that is Fatal{ProtocolCorruption}, not a dropped call.
+        Uint64 RefusedObjectCalls = 0;
+
+        // P4a's BELT (ID-39): every call in one of the four families P4a migrates that this
+        // applier declined because NO BACKEND HAS REGISTERED MGPipeResourceOps - i.e. because
+        // nothing in this process consumes what the record publishes.
+        //
+        // WHY THE APPLIER ASKS A QUESTION ABOUT THE BACKEND AT ALL, when it is otherwise
+        // backend-neutral: acceptance is a CONTRACT WITH THE CLIENT since ID-18 M3. The
+        // emitters clear a texture level's dirty flags, advance their descriptor mirrors and
+        // latch their suppressors on the answer this applier returns, so an applier that
+        // accepts a record nothing will ever read makes the client forget work the legacy pull
+        // path still owed - which is exactly how 66 texture-upload-shaped DirectVulkan cases
+        // went red on the push build (ID-39). The client's own gate
+        // (MG_Impl/Pipe/PipeFill.cpp's FamilyIsLive) stops the emission upstream; this is the
+        // belt under it, so a record that reaches here by any other route - GL_Framebuffer.cpp's
+        // PipePublishFramebufferByName calls its emitter directly, without passing PipeFill -
+        // is declined rather than accepted.
+        //
+        // IT IS NOT A DEFECT COUNTER, WHICH IS WHY IT IS SILENT. RefusedResourceCalls,
+        // RefusedVertexInputCalls and RefusedObjectCalls each mean "a record named something
+        // this applier should have had"; a non-zero value there is a seam defect. A non-zero
+        // value HERE is the designed steady state of a backend with no P4a twins, so logging it
+        // would put an ERROR line in every ordinary Magma run. The number is the observable.
+        //
+        // THE DEATH PATHS ARE DELIBERATELY NOT ON THIS LIST. resource_destroy,
+        // delete_sampler_state, delete_sampler_view and delete_shader_state are idempotent
+        // cleanup that must keep working whatever the registration did, and with no consumer
+        // there is no record for them to find anyway (they count their own refusal). Per
+        // context and cleared by MGPipeApplierReset, like the three above it.
+        Uint64 RefusedNoConsumer = 0;
 
         // ---- working state: what the next draw fetches with. All of it is per context and
         // all of it is cleared by MGPipeApplierReset, EXCEPT the two serials, which only ever
@@ -271,6 +595,89 @@ namespace MobileGL::MG_Pipe {
         // operator greps is PipeStats' map-persistent-roundtrips (mpr); this member is the
         // applier-side observable a unit case reads without a stats window.
         Uint64 MapPersistentRoundtrips = 0;
+
+        // ---- P4a's WORKING state. All of it is per context and all of it is cleared by
+        // MGPipeApplierReset, EXCEPT the serials, which only ever advance - a counter that
+        // restarts walks back through values already stamped into a twin that outlived the
+        // switch, and P4a deletes the identity patches that used to close that hole.
+
+        // WHICH FRAMEBUFFER IS BOUND TO EACH BINDING, and that is ALL this pair is since
+        // ID-19(b): the record itself lives in FramebufferRecords above, keyed by the handle.
+        // Indexed by MGPipeFramebufferTarget::Draw / ::Read. kMGPipeNullHandle means "nothing
+        // described this binding yet", which is what a make-current leaves behind.
+        //
+        // set_framebuffer_state Draw / Read / Both writes the RECORD at state.Fbo's slot AND
+        // sets the handle(s) here; Named (MGPipeFramebufferTarget::Named) writes the record and
+        // touches nothing here at all - that is the whole of the fourth target's meaning.
+        Array<MGPipeHandle, kMGPipeFramebufferBindingCount> BoundFramebuffer{};
+        // ONE SERIAL FOR THE FAMILY, and it moves on EVERY write - a Named record's included,
+        // because a twin memoising "the framebuffer state I have seen" has to hear about a
+        // named framebuffer's attachments exactly as it hears about a bound one's. It is the
+        // number that retires the four g_fboSynced* arrays and the twin's {slot version, object
+        // version, backend id generation} triple.
+        Uint64 FramebufferSerial = 0;
+        // Every FramebufferRecordFor() that found a record at the slot whose GENERATION had
+        // moved on. It is NOT RefusedObjectCalls: this is a READ by the server's own sync path
+        // and not a call this applier refused, and set_framebuffer_state's counter contract
+        // (below) is that no framebuffer call ever moves that one. A non-zero value here is a
+        // seam defect - an emitter minted a successor for a recycled slot and never described
+        // it, or handed out a handle it had already retired - so it is counted AND logged, and
+        // a unit case reads it in every build for the reason the other counters exist.
+        //
+        // `mutable` because the three accessors below are const: package E holds the applier
+        // through a `const auto&` and must keep doing so.
+        mutable Uint64 StaleFramebufferRecordLookups = 0;
+
+        // The three kVarTail unit sets, as received. NO STAGE DIMENSION: MobileGL's
+        // texture-unit space is one merged array of 192, the same unit may be sampled from two
+        // stages, and stage is derived server-side from the reflection archive only where the
+        // target API needs it.
+        //
+        // THE VAR-TAIL WINDOW IS THE BOUND AND ENTRIES OUTSIDE IT ARE NOT CLEARED - the
+        // record is "the last set as received", exactly as set_vertex_buffers is, and
+        // Start + Count above the bound is Fatal{ProtocolCorruption}.
+        Array<MGPBoundView, kMGPipeMaxTextureUnits> BoundSamplerViews{};
+        Uint32 SamplerViewStart = 0;
+        Uint32 SamplerViewCount = 0;
+        Uint64 SamplerViewsSerial = 0;
+
+        Array<MGPipeHandle, kMGPipeMaxTextureUnits> BoundSamplerStates{};
+        Uint32 SamplerStateStart = 0;
+        Uint32 SamplerStateCount = 0;
+        Uint64 SamplerStatesSerial = 0;
+
+        Array<MGPImageView, kMGPipeMaxImageUnits> BoundShaderImages{};
+        Uint32 ShaderImageStart = 0;
+        Uint32 ShaderImageCount = 0;
+        Uint64 ShaderImagesSerial = 0;
+
+        // set_draw_program / set_dispatch_program are two calls because the frontend has two
+        // joins and two PipeInputs slots; bind_shader_state is the third, and a null handle is
+        // legal in all three and means "nothing bound".
+        MGPipeHandle DrawProgram = kMGPipeNullHandle;
+        MGPipeHandle DispatchProgram = kMGPipeNullHandle;
+        MGPipeHandle BoundShaderCso = kMGPipeNullHandle;
+        Uint64 ProgramBindingSerial = 0;
+
+        // ---- THE THREE FRAMEBUFFER ACCESSORS (ID-19(b)/(d)). They are functions rather than
+        // members because the storage moved under them and their callers must not have to know
+        // it did: `DrawFramebuffer()` / `ReadFramebuffer()` answer the question the two members
+        // used to answer - "which record describes the framebuffer bound to this binding" - by
+        // resolving BoundFramebuffer[t] through FramebufferRecords.
+        //
+        // NULL IS A REAL ANSWER AND HAS EXACTLY THREE CAUSES: nothing is bound to that binding
+        // (the null handle, which is what a make-current leaves and is NOT an error), no record
+        // has been written at that slot, or the slot's generation has moved on under the handle
+        // (which IS an error and is counted and logged - see StaleFramebufferRecordLookups). A
+        // caller that used to test `MGPipeHandleIsNull(st.DrawFramebuffer.Fbo)` tests the
+        // pointer instead; the two are the same question.
+        //
+        // Defined in PipeApply.cpp rather than inline HERE so this header keeps its include
+        // closure: the stale-generation path logs, and MG_Util/Debug/Log.h is not in this
+        // header's closure and may not become part of it.
+        const MGPFramebufferState* FramebufferRecordFor(MGPipeHandle fbo) const;
+        const MGPFramebufferState* DrawFramebuffer() const;
+        const MGPFramebufferState* ReadFramebuffer() const;
     };
 
     // The monolith's single applier. Under split there is one per served context.
@@ -288,6 +695,30 @@ namespace MobileGL::MG_Pipe {
     // vertex-input serials rather than zeroing them. It does NOT drop the resource or
     // vertex-elements records: those describe share-group objects that the switch does not
     // destroy, and dropping them is a dropped write on the far side of it.
+    //
+    // P4a EXTENDS BOTH HALVES AND THE RULE IS UNCHANGED (D-J4). Cleared: the two framebuffer
+    // BINDINGS, the three unit sets, DrawProgram / DispatchProgram / BoundShaderCso - all of it
+    // per-context working state - with their serials ADVANCED and never zeroed. Not cleared:
+    // texture and renderbuffer resources, sampler CSOs, sampler views, shader CSOs, the
+    // framebuffer RECORDS, and the texture params and pending uploads that ride on a resource
+    // record, because a texture lives in a share group exactly as a buffer does.
+    //
+    // ID-19(b) MOVED THE FRAMEBUFFER RECORD ACROSS THAT LINE and the reason is worth stating.
+    // Before it, the whole framebuffer state was working state and a make-current took it. Now
+    // the RECORD is an object record and only the two BOUND HANDLES are working state, so a
+    // switch clears the bindings - after which DrawFramebuffer() / ReadFramebuffer() answer
+    // null, exactly as the cleared records used to answer a null Fbo - and leaves the table
+    // standing. Dropping the table instead would silently lose the record of every framebuffer
+    // that is described by NAME and never bound, because the client's re-emission on a fresh
+    // context is driven by MGPipeSetHashSuppressor::InvalidateAll, which re-sends the two bound
+    // records and nothing else.
+    //
+    // AND THEREFORE NO P4a TRACKER NEEDS A RE-PUBLICATION PATH ON FreshlyPrimed, AND NONE MAY
+    // HAVE ONE: re-emitting create_sampler_state for a record the applier still holds would
+    // move its Serial for nothing. What DOES reset on a fresh context is each emitter's
+    // BOUND-HANDLE latch - the framebuffer and unit-set hashes through
+    // MGPipeSetHashSuppressor::InvalidateAll, and the program emitter's BoundShaderCso mirror -
+    // because those mirror working state this function just cleared.
     void MGPipeApplierReset();
 
     // THE OTHER SCOPE: the served context is going away and its applier with it, so the object
@@ -344,18 +775,127 @@ namespace MobileGL::MG_Pipe {
     // the backend and the gates compile against, and the records above are what they write
     // into; the bodies land in the two commits that follow this one on the same branch.
 
+    // The scope of one resource_respecify, and it is an APPLIER-SIDE ARGUMENT and not a wire
+    // record: it is not in PipeFields.def, it crosses no payload, and the transport reads the
+    // scope off the call it is replaying rather than off a field. The two members mirror
+    // MGPipeResourceRecord::PendingUpload's key exactly, which is the only thing the applier
+    // does with them - so UploadTarget is MGPSubData::Target VERBATIM, the whole packed field
+    // (ID-12: low byte = MGPipeResourceTarget, high byte = the cube-face upload target), the
+    // same value the emission of that level put in the record. A per-face respecify therefore
+    // drops the face it redefines and leaves the other five standing, and a caller that packs
+    // the pair differently here than it packs it there simply matches nothing.
+    // A NAMED LEVEL IS DROPPED EVEN WHEN EVERY STORAGE-DEFINING FIELD IS UNCHANGED (P4a final
+    // review C-1): the pointer is the caller's statement that it reallocated that level, and
+    // a non-base level's extent is not in the descriptor. Only a NULL level with unchanged
+    // fields is the metadata update that drops nothing (ID-18 M4); the client's mask republish
+    // is the one caller of that shape and passes null on purpose.
+    struct MGPRespecifiedLevel {
+        Uint16 UploadTarget = 0;
+        Uint16 Level = 0;
+    };
+
+    // THE THREE ACCEPTANCE RETURNS, AND WHY ALL THREE (ID-18 M3, clientfb review M3). D-D5
+    // step 1 says the client clears a level's dirty flags "for the levels whose record the
+    // applier ACCEPTED", and the emitter cannot answer that for itself: an `if constexpr` that
+    // discarded the call, a dead or stale handle (a counted no-op) and a corrupt record (a Fatal
+    // that deliberately moves no counter) are all invisible from the call site, so a client that
+    // clears on the strength of having EMITTED drops those texels for good. resource_subdata
+    // returns it, and so must the two calls that DEFINE the storage a subsequent upload lands
+    // in - a create or a respecify the applier refused leaves no record for the upload to
+    // accumulate onto, and B's own bookkeeping (its per-entry descriptor dedupe, its drain list)
+    // must not advance past a call that never landed.
+    //
+    // ALL THREE ARE SOURCE-COMPATIBLE: a Bool return is ignorable, P3a's call sites in
+    // MG_Impl/Pipe/PipeFill.cpp discard it, and gen_pipe.py never parses this header - the wire
+    // path calls no MGPipeApply* at all (wire review W1), so PipeCalls.def and
+    // MobileGL/MG_Pipe/generated do not move.
+
     // resource_create: mints the record and marks the slot Live. Emitted from the buffer
     // object's CONSTRUCTOR, so a resource exists before anything can name it; storage is
     // defined lazily by the first respecify and a backend tolerates a resource with none.
-    void MGPipeApplyResourceCreate(const MGPResourceDesc& desc);
+    //
+    // Returns true when the record was minted. False for the three refusals: the reserved slot
+    // 0, a descriptor whose target names no resource kind, and a slot at or above
+    // kMGPipeMaxResourceSlots.
+    Bool MGPipeApplyResourceCreate(const MGPResourceDesc& desc);
     // resource_respecify: replaces the stored descriptor and bumps Serial. `initialBytes` is
     // the shadow when desc.HasDefinedContent, else null. kNeedsAck on the call,
     // MGPipeResourceRespecifyNeedsAck(desc) per record - only an immutable store acks.
-    void MGPipeApplyResourceRespecify(const MGPResourceDesc& desc, const void* initialBytes);
+    //
+    // P4a: `level` IS THE SCOPE OF THE REDEFINITION, and MGPResourceDesc cannot carry it - the
+    // descriptor describes the resource, and a mutable texture redefines its levels ONE
+    // glTexImage*D AT A TIME. Null means "this respecify redefines the WHOLE resource" - every
+    // glBufferData / glBufferStorage, every glTexStorage*, every texture view - and drops every
+    // pending upload, which is right because every level's coordinate system has just been
+    // replaced. Non-null names the single (uploadTarget, level) the call redefines and drops
+    // ONLY that key: the frontend's AllocateStorage / MarkStorageDirty are per
+    // (uploadTarget, level) as well (MG_State/GLState/TextureState/TextureObject.h), so a
+    // glTexImage2D(level 1) re-marks level 1 AND NOTHING ELSE, while the levels already
+    // emitted had their client dirty flags cleared at THEIR emission (D-D5 step 1) and nothing
+    // anywhere still owes them. Clearing the whole set here would lose exactly those texels,
+    // silently, in every build - the loss the server-side set exists to prevent.
+    //
+    // Trailing and defaulted for W1's reason: P3a's buffer call site (PipeFill.cpp:691) and
+    // every existing case compile unchanged. PACKAGE B PASSES THE PAIR IT JUST ALLOCATED at
+    // every per-level respecify; it has both halves in hand at the AllocateStorage call site.
+    //
+    // A METADATA RESPECIFY IS A RESPECIFY THAT REDEFINES NO STORAGE (ID-18 M4). A sticky
+    // BindMask / ImageBindableHint bit reaches the applier only on a respecify, and an
+    // IMMUTABLE texture has no further one - that is what immutable means - so the canonical
+    // order (glTexStorage2D, then glBindImageTexture or an FBO attachment) would leave the
+    // record's hint at 0 for ever, and the hint is the PREVENTION half of the texture-remint
+    // stall class. So B re-emits the descriptor when the mask moves, and a record whose
+    // STORAGE-DEFINING fields all equal the stored descriptor's is applied as a metadata
+    // update:
+    //
+    //   - the descriptor is replaced, so BindMask and ImageBindableHint take their new values;
+    //   - NO pending upload is dropped, whatever `level` says. This REFINES the rule above
+    //     rather than contradicting it: that rule drops the uploads against the storage a
+    //     respecify REPLACES, and a call that replaces no storage replaces no coordinate system
+    //     either, so there is nothing to drop. A mask change arriving between a
+    //     glTexSubImage2D and the sync that consumes it must not eat the texels;
+    //   - the serial advances, which is the whole publication - the twin re-derives its storage
+    //     flags from the new mask at its next sync and recreates only where the backend needs
+    //     it (D's side);
+    //   - and MGPipeResourceRespecifyNeedsAck is false for it BY CONSTRUCTION, because a buffer
+    //     is never classified this way (see the body: glBufferData at an unchanged size is a
+    //     real orphaning reallocation, and glBufferStorage is the one entry point allowed a
+    //     synchronous ack).
+    //
+    // Returns true when the descriptor was stored - metadata updates included, since the record
+    // did move - and false when the call was refused: a descriptor whose target names no
+    // resource kind, or a handle this applier has no live record for at that generation.
+    Bool MGPipeApplyResourceRespecify(const MGPResourceDesc& desc, const void* initialBytes,
+                                      const MGPRespecifiedLevel* level = nullptr);
     // resource_subdata, buffer half: the destination range rides in the record's box through
     // MGPipeSetSubDataBufferRange, and a false from that helper is where the EMITTER split.
     // The applier stores nothing per record - contents are the backend's - and bumps Serial.
-    void MGPipeApplyResourceSubData(const MGPSubData& record, const void* bytes);
+    //
+    // P4a: `regions` IS THE CALL'S VARIABLE TAIL - MGPSubRegion[record.RegionCount] - and it is
+    // a trailing DEFAULTED parameter rather than a second entry point. The call has carried
+    // kVarTail since P2 (PipeCalls.def) and the texture half cannot be applied without it: the
+    // applier's pending-upload set is (UnionBox, RegionCount, Regions[]) and the verify lane's
+    // retain mode compares all three. The buffer half declares no regions, so P3a's one call
+    // site and every existing case are unchanged by the default.
+    //
+    // THE RETURN IS THE ACCEPTANCE SIGNAL D-D5 STEP 1 NAMES: true when the record was stored -
+    // the buffer half landed its range, or the texture half accumulated the shape onto the
+    // record - and false when it was refused. THE EMITTER MUST GATE ITS DIRTY-FLAG CLEAR ON IT
+    // ("only for levels whose record the applier ACCEPTED"), because the two refusal paths are
+    // otherwise invisible to it: a dead or stale handle is a counted no-op and a corrupt record
+    // is a Fatal that does NOT move RefusedResourceCalls, so in a shipped push build a refused
+    // upload and an accumulated one are indistinguishable from the call site. A client that
+    // clears on the strength of having emitted drops those texels for good.
+    //
+    // THE RESOURCE-TARGET HALF OF record.Target PICKS THE HALF. MGPSubData::Target is PACKED
+    // (ID-12): low byte = MGPipeResourceTarget, high byte = the cube-face upload target. The
+    // buffer half is the whole field being 0 - the encoding the emitter is held to, since a
+    // buffer has no upload target - and the texture half additionally requires the low byte to
+    // name a TEXTURE target: Buffer, Renderbuffer and anything at or above
+    // MGPipeResourceTarget::Count are Fatal{ProtocolCorruption} rather than an upload onto
+    // whatever object holds that slot in the texture slot space.
+    Bool MGPipeApplyResourceSubData(const MGPSubData& record, const void* bytes,
+                                    const MGPSubRegion* regions = nullptr);
     // buffer_subdata_resident: same shape; `bytes` is the application's staging store and is
     // valid for the duration of the call only. The op-table entry may be null.
     void MGPipeApplyBufferSubDataResident(const MGPSubData& record, const void* bytes);
@@ -403,6 +943,130 @@ namespace MobileGL::MG_Pipe {
     // configuration. Bumps IndexBufferSerial.
     void MGPipeApplySetIndexBuffer(const MGPIndexBuffer& record);
 
+    // ---------------------------------------------------------------------------------
+    // P4a: the fifteen object and working-state entry points (D-A1, D-B1, D-J1)
+    // ---------------------------------------------------------------------------------
+    //
+    // NOT ONE OF THEM DISPATCHES TO A BACKEND FUNCTION POINTER, and that is the single most
+    // important structural decision in P4a rather than an omission. Nothing in these families
+    // reaches the backend at GL-call time today - texture storage only marks a level dirty and
+    // Espryt allocates lazily at sync, texture params run from SyncTextureObjectToBackend at
+    // draw sync, renderbuffer storage is allocated inside SyncToBackend on a four-field cache,
+    // a sampler twin is created lazily from the program pass, and the framebuffer, unit sets
+    // and program are all resolved at PrepareForDraw. So every call below is either an OBJECT
+    // RECORD the applier stores or WORKING STATE the applier stores, and Espryt reads the
+    // applier at the sync points it already has, keyed on a server-owned Serial instead of a
+    // frontend version. MGPipeResourceOps is therefore UNCHANGED - nine members, same
+    // signatures - and P4a adds no backend op table and no op-table member at all.
+    //
+    // The consequence for the four resource entry points above: they BRANCH on
+    // record.Desc.Target. A buffer target dispatches into MGPipeResourceOps exactly as P3a
+    // wrote it; every other target stores and returns. The branch is one comparison against
+    // kMGPipeResourceTargetBuffer and it is where a mis-typed descriptor becomes visible.
+    //
+    // AT THE CONTRACT COMMIT EVERY BODY BELOW IS A STUB, exactly as P3a's nine were: the
+    // signatures are what the client, the backend and the gates compile against and the
+    // records above are what they write into; the bodies land in the three commits that
+    // follow this one on the same branch.
+
+    // set_framebuffer_state. Fully resolved - nothing in the record requires a lookup on the
+    // far side. ContentHash covers every field including Fbo and DrawBuffers[8], which is what
+    // makes a suppressed record provably mean "the draw-buffer array did not move" and
+    // therefore "the fragColor broadcast count did not move".
+    //
+    // `state.Target` NOW SAYS TWO THINGS AT ONCE (ID-19(b)), and the record always does the
+    // first of them:
+    //
+    //   - THE RECORD IS ALWAYS WRITTEN, at FramebufferRecords[state.Fbo.Slot], whatever the
+    //     target is. The table is keyed by the framebuffer HANDLE, so one framebuffer's record
+    //     can never displace another's, and a slot whose object has been recycled is simply
+    //     overwritten by its successor's record (D-I2: no wire lifetime, so nothing to retire).
+    //   - Draw / Read / Both ADDITIONALLY set BoundFramebuffer[Draw] / [Read] / both.
+    //     MGPipeFramebufferTarget::Named sets NEITHER: it is how a DSA entry point hands Espryt
+    //     a framebuffer it is about to blit into or clear WITHOUT claiming it is bound.
+    //
+    // FramebufferSerial advances on every applied record, Named included.
+    //
+    // Two refusals, both Fatal{ProtocolCorruption} and neither counted (see RefusedObjectCalls:
+    // this entry point resolves nothing and can only ever fault): a target above Named, a
+    // draw-buffer entry outside the record's own Color[], a slot at or above
+    // kMGPipeMaxFramebufferSlots, and the NULL HANDLE - a record that named {0,0} would install
+    // itself where "nothing is bound" is read, and every emitter has a handle for every
+    // framebuffer it describes (kMGPipeDefaultFramebuffer {0,1} for the default one).
+    void MGPipeApplySetFramebufferState(const MGPFramebufferState& state);
+
+    // create_sampler_state. `parameters` is the client's canonical SamplerParameters copy,
+    // beside the record for the one Blob rule's reason; the applier stores it by value.
+    void MGPipeApplyCreateSamplerState(const MGPSamplerDesc& desc, const SamplerParameters* parameters);
+    // delete_sampler_state: emitted by the CSO cache's LRU eviction and by the frontend
+    // sampler object's death helper. Clears Live and drops the record; the client frees the
+    // slot afterwards.
+    void MGPipeApplyDeleteSamplerState(const MGPHandleOnly& handle);
+
+    // create_sampler_view. Re-issued on the SAME handle whenever the view restrictions move,
+    // which is legal because Gen increments only on slot reuse and never on a respecify.
+    void MGPipeApplyCreateSamplerView(const MGPSamplerView& view);
+    void MGPipeApplyDeleteSamplerView(const MGPHandleOnly& handle);
+
+    // set_texture_params: addressed by RESOURCE and independent of any binding, which is what
+    // lets a texture that is only an attachment, only an image-unit binding or only a
+    // glCopyImageSubData endpoint carry its parameters at all. params.BuiltinSampler may never
+    // be the null handle - every ITextureObject owns a sampler object - so a null is
+    // Fatal{ProtocolCorruption} rather than "no sampler".
+    //
+    // Returns true when the record took the parameters (P4a final review m-1, audit F-7): the
+    // emitter's version latch advances on this answer and on nothing else, the way the
+    // sub-data and respecify paths latch on theirs, so a refused record - no consumer, no
+    // record for the handle, a null sampler - is re-sent at the next call rather than at the
+    // next glTexParameter*. Source-compatible for the same reason the three resource returns
+    // are: a Bool is ignorable and gen_pipe never parses this header.
+    Bool MGPipeApplySetTextureParams(const MGPTextureParams& params);
+
+    // set_sampler_views / bind_sampler_states / set_shader_images: `tail` is hdr.Count entries
+    // starting at hdr.Start, and hdr.Start + hdr.Count above the unit bound is
+    // Fatal{ProtocolCorruption}. Entries outside the declared window are NOT cleared.
+    void MGPipeApplySetSamplerViews(const MGPSamplerViews& hdr, const MGPBoundView* tail);
+    void MGPipeApplyBindSamplerStates(const MGPSamplerStates& hdr, const MGPipeHandle* tail);
+    void MGPipeApplySetShaderImages(const MGPShaderImages& hdr, const MGPImageView* tail);
+
+    // create_shader_state. THE ARTEFACTS TRAVEL BESIDE THE RECORD, by pointer: all seven of
+    // desc.Spirv[] and desc.Reflection are declared with Size 0 ("this record does not declare
+    // its blob"), which is what a monolith emission is, and the codec is NOT called - zero
+    // serialisation cost on the monolith path. A verify build serialises, deserialises and
+    // field-compares before storing, and a mismatch is Fatal{PipeVerifyDiffer, "program-archive"}.
+    // Splitting this record for a transport whose ring caps one record at half its capacity is
+    // P5's problem, not this entry point's.
+    void MGPipeApplyCreateShaderState(const MGPProgramDesc& desc,
+                                      const MG_State::GLState::LinkArtifacts* link,
+                                      const MG_State::GLState::SpirvArtifacts* spirv);
+    void MGPipeApplyBindShaderState(const MGPHandleOnly& handle);
+    void MGPipeApplyDeleteShaderState(const MGPHandleOnly& handle);
+    void MGPipeApplySetDrawProgram(const MGPHandleOnly& handle);
+    void MGPipeApplySetDispatchProgram(const MGPHandleOnly& handle);
+
+    // set_global_constants: the DEFAULT UNIFORM BLOCK only. Keyed (ShaderCso, Version) and
+    // emitted at most once per program per frame; `bytes` is MapUBO()'s image, GetUBOSize()
+    // long, handed over as a companion pointer with Blob.Size 0. record.Version is
+    // GetUBOContentVersion() and may never be ~0u, which is the backends' "never uploaded"
+    // sentinel.
+    void MGPipeApplySetGlobalConstants(const MGPGlobalConstants& record, const void* bytes);
+
+    // ---------------------------------------------------------------------------------
+    // P4a: the named, greppable unmigrated emulations (D-M)
+    // ---------------------------------------------------------------------------------
+    //
+    // ROADMAP.md's P4a row ends "emulation 在 split 下显式 Fatal 直到 P8". In monolith the
+    // code paths keep running exactly as today - the Fatal is a SPLIT-only arm - so this costs
+    // P4a a named call site per unmigrated emulation and nothing else. P5/P8 give it teeth: a
+    // split server that reaches one of these has no client address space to read and must
+    // abort loudly rather than degrade silently.
+    //
+    // Monolith body: (void)name;. The list of names is pinned by
+    // PipeCatalogueTest.EveryUnmigratedEmulationIsNamedOnce and the call count is grepped by
+    // the purity gate, so a site that quietly disappears is a red gate rather than a surprise
+    // at P8.
+    void MGPipeUnmigratedEmulation(const char* name);
+
     // ---------------------------------------------------------------------------------
     // The derivation step (ARCHITECTURE.md 5.3, P2 brief D5)
     // ---------------------------------------------------------------------------------

MobileGL/MG_Pipe/PipeCalls.def

@@ -23,6 +23,14 @@
 //             (MGPipeTypes.h) is what says so, which is why the same call still carries
 //             every glBufferData without acknowledging one.
 //
+//             kHasBlob MEANS "THE PAYLOAD OWNS AN MGPBlobRef MEMBER", nothing weaker (P5
+//             R-13.1). It is not "this call carries bytes": three calls carry bytes with no
+//             MGPBlobRef at all and they are named in CONTRACT-P5.md table 1, not flagged
+//             here, because a decoder that trusts kHasBlob has to find a member to read.
+//             The flags are EXPORTED, once, as kMGPipeCallFlags[] in generated/PipeWire.inc
+//             (P5 R-13.4): before that table existed every consumer hard-coded its own copy,
+//             which is how the two carriers below came to disagree with their payloads.
+//
 // RECORD NUMBERING NEVER CHURNS. Entries that are not implemented yet still occupy their
 // line (plan section 11, P0: "the complete call catalogue, placeholders included"). A new
 // call is APPENDED to its group; a retired call keeps its slot with a comment. The wire
@@ -77,8 +85,20 @@
 // clang-format off
 #define MGP_CALL_LIST(X)                                                                            \
     /* ---- screen: caps, resources, persistent map, fences (plan 4.4.1) ---- */                    \
-    X(GetCaps,                  MGPCaps,                    kScreen,    kReplySlot)                 \
+    /* kHasBlob because MGPCaps owns TWO MGPBlobRef members - FormatCapabilities and      */  \
+    /* RendererInfo (MGPipeTypes.h). It carried none until P5 R-13.1; the flag is a        */  \
+    /* property of the payload, so its absence was simply wrong. Adding a flag does not    */  \
+    /* move an opcode: the opcode is this line's 1-based position.                          */  \
+    X(GetCaps,                  MGPCaps,                    kScreen,    kReplySlot|kHasBlob)     \
     X(ResourceCreate,           MGPResourceDesc,            kScreen,    kNone)                      \
+    /* NO kHasBlob, BY RULING (P5 R-13.3; CONTRACT-P5.md table 1 row 19). MGPResourceDesc   */  \
+    /* owns no MGPBlobRef and gains none: under split `initialBytes` is always nullptr and  */  \
+    /* the initial content of a glBufferData(size, data) / glTexImage*(..., data) arrives   */  \
+    /* as resource_subdata records IMMEDIATELY AFTER this one. Reuses a path that is        */  \
+    /* already chunked (MGPipeForEachSubDataRecordRange) and already acceptance-gated; the  */  \
+    /* cost is one extra record. NOTE the SECOND uncarried companion on this call, the      */  \
+    /* MGPRespecifiedLevel* scope (PipeApply.h:792) - it is NOT bytes and NOT covered by    */  \
+    /* this ruling; table 1 row 19 gives it the two pad fields of MGPResourceDesc.          */  \
     X(ResourceRespecify,        MGPResourceDesc,            kScreen,    kNeedsAck)                  \
     X(ResourceDestroy,          MGPHandleOnly,              kScreen,    kNone)                      \
     X(MapPersistent,            MGPHandleOnly,              kScreen,    kReplySlot|kOptional)       \
@@ -101,7 +121,11 @@
     X(CreateVertexElements,     MGPVertexElements,          kCtxCso,    kHasBlob)                   \
     X(BindVertexElements,       MGPHandleOnly,              kCtxCso,    kNone)                      \
     X(DeleteVertexElements,     MGPHandleOnly,              kCtxCso,    kNone)                      \
-    X(CreateSamplerState,       MGPSamplerDesc,             kCtxCso,    kNone)                      \
+    /* kHasBlob because MGPSamplerDesc owns an MGPBlobRef member, `Parameters` - the        */  \
+    /* SamplerParameters POD byte for byte, borderColorForm included (P5 R-13.1). The       */  \
+    /* companion pointer beside the record today is a TYPED frontend pointer               */  \
+    /* (const SamplerParameters*), which is exactly what split may not carry.              */  \
+    X(CreateSamplerState,       MGPSamplerDesc,             kCtxCso,    kHasBlob)                   \
     X(DeleteSamplerState,       MGPHandleOnly,              kCtxCso,    kNone)                      \
     X(CreateSamplerView,        MGPSamplerView,             kCtxCso,    kNone)                      \
     X(DeleteSamplerView,        MGPHandleOnly,              kCtxCso,    kNone)                      \
@@ -134,6 +158,13 @@
     X(ResourceSubData,          MGPSubData,                 kCtxObject, kHasBlob|kVarTail)          \
     X(BufferSubDataResident,    MGPSubData,                 kCtxObject, kHasBlob|kOptional)         \
     X(ResourceSubDataComplete,  MGPSubDataComplete,         kCtxObject, kNone)                      \
+    /* NO kHasBlob AND NO MGPBlobRef, BY RULING (P5 R-13.2; CONTRACT-P5.md table 1 row 21). */  \
+    /* It takes a content pointer today, but under split it CARRIES NO BYTES AT ALL: it is  */  \
+    /* a {range, AccessFlags} control record, and the bytes of [Offset, Offset+Size) arrive  */  \
+    /* AHEAD of it as resource_subdata records covering exactly that range. The ladder this  */  \
+    /* drives rewrites its range "from the authoritative shadow" (Managers.cpp:1047-1076),   */  \
+    /* and under split the authoritative shadow is server-owned (R-11), so subdata is the    */  \
+    /* only way bytes reach it - a blobref here would be a SECOND way to say the same thing. */  \
     X(ResourceFlushRange,       MGPFlushRange,              kCtxObject, kNone)                      \
     X(ResourceReadback,         MGPReadback,                kCtxObject, kReplySlot)                 \
     X(ResourceCopyRegion,       MGPCopyRegion,              kCtxObject, kNone)                      \

MobileGL/MG_Pipe/PipeFields.def

@@ -41,10 +41,16 @@
 #define MGP_FIELDS_MGPCaps(F) \
     F(Dynamic) F(CallMask) F(FormatCapabilities) F(RendererInfo)
 
+// The three respecify-scope fields are listed like any other member: they occupy what used to be
+// Pad0's high byte and Pad1, and the generator's cover check only excludes members actually
+// NAMED Pad*, so leaving them out would fail --check rather than pass it. They are also real
+// G4 comparands - a verify build that let the scope differ silently would be blind to the one
+// thing that decides whether a respecify drops one pending upload or all of them.
 #define MGP_FIELDS_MGPResourceDesc(F) \
     F(Resource) F(Target) F(StorageKind) F(BindMask) F(InternalFormat) F(Width) F(Height) F(Depth) \
     F(ArrayLayers) F(Levels) F(Samples) F(FixedSampleLocations) F(Immutable) F(Usage) F(StorageFlags) \
-    F(HasDefinedContent) F(ImageBindableHint) F(GlNameForDiag) F(ViewOf) F(BufferForTexBuffer) \
+    F(HasDefinedContent) F(ImageBindableHint) F(HasRespecifiedLevel) F(GlNameForDiag) \
+    F(RespecifiedUploadTarget) F(RespecifiedLevel) F(ViewOf) F(BufferForTexBuffer) \
     F(BufOffset) F(BufSize)
 
 #define MGP_FIELDS_MGPFenceWait(F) \
@@ -78,20 +84,30 @@
     F(Cso) F(Texture) F(InternalFormat) F(Target) F(MinLevel) F(NumLevels) F(MinLayer) F(NumLayers) \
     F(Samples) F(FixedSampleLocations)
 
+// P4a, D-E1: BuiltinSampler and SamplerResync. Pad0 stays unlisted - gen_pipe.py's
+// PADDING_MEMBER_RE (^Pad\d*$) excludes it, and a member that stops being called Pad<n> MUST
+// gain a row here or pipe-gates goes red.
 #define MGP_FIELDS_MGPTextureParams(F) \
-    F(Res) F(BaseLevel) F(MaxLevel) F(Swizzle) F(DepthStencilMode) F(ForceResync) F(MinLod) F(MaxLod) \
-    F(LodBias)
+    F(Res) F(BuiltinSampler) F(BaseLevel) F(MaxLevel) F(Swizzle) F(DepthStencilMode) F(ForceResync) \
+    F(SamplerResync) F(MinLod) F(MaxLod) F(LodBias)
 
 #define MGP_FIELDS_MGPProgramDesc(F) \
     F(Cso) F(StageMask) F(GlobalUboSize) F(ReservedNumSamplesOffset) F(SpirvStatus) F(NativeFloat64) \
     F(PointSizeDemoted) F(EnableSpirvValidation) F(Spirv) F(Reflection)
 
+// P4a, ID-12 / esprytobj DV-5: Pad0 became Uint16 TextureTarget. Same trip wire as
+// MGPFramebufferState's Target below - PADDING_MEMBER_RE only excludes a member still NAMED
+// Pad<n>, so the rename without this row is a pipe-gates failure, and the row without the
+// rename is one too. A meaning-carrying byte cannot enter this record silently.
 #define MGP_FIELDS_MGPSurface(F) \
-    F(Res) F(InternalFormat) F(Kind) F(Layered) F(Level) F(Layer) F(UploadTarget)
+    F(Res) F(InternalFormat) F(Kind) F(Layered) F(Level) F(Layer) F(UploadTarget) F(TextureTarget)
 
+// P4a, D-C2: Pad0 became Uint8 Target, and gen_pipe.py's PADDING_MEMBER_RE only excludes a
+// member still NAMED Pad<n> - so the rename without this row is a pipe-gates failure, which
+// is exactly the trip wire that makes the byte impossible to add silently.
 #define MGP_FIELDS_MGPFramebufferState(F) \
     F(Fbo) F(Color) F(Depth) F(Stencil) F(ReadSurface) F(DrawBuffers) F(Width) F(Height) F(Layers) \
-    F(Samples) F(FixedSampleLocations) F(IsDefault) F(Complete) F(ContentHash)
+    F(Samples) F(FixedSampleLocations) F(IsDefault) F(Complete) F(Target) F(ContentHash)
 
 #define MGP_FIELDS_MGPVertexBuffer(F) \
     F(Res) F(Offset) F(Stride) F(Divisor) F(BindingIndex)
@@ -254,6 +270,18 @@
     F(SwapBytes) F(LSBFirst) F(RowLength) F(ImageHeight) F(SkipPixels) F(SkipRows) F(SkipImages) \
     F(Alignment)
 
+// P4a, D-F1: THE PADDING TRAP. SamplerParameters is sizeof == 100 with THREE BYTES OF
+// TRAILING PADDING (96 bytes of members plus the 1-byte borderColorForm) and had no field
+// table and no MGP_VERIFY_PAYLOAD_LIST row at all, so MGPSamplerDesc's blob was compared as
+// BYTES and MOBILEGL_PIPE_VERIFY could false-differ on uninitialised padding - a coin flip
+// rather than a gate. With this list the comparator sees the sixteen members and the three
+// bytes can never enter the answer. The client-side CSO cache hashes and memcmp-confirms over
+// a ZERO-INITIALISED canonical copy for the same reason, which is the other half of D-F1.
+#define MGP_FIELDS_SamplerParameters(F) \
+    F(wrapS) F(wrapT) F(wrapR) F(minFilter) F(magFilter) F(mipmapMode) F(minLod) F(maxLod) \
+    F(lodBias) F(maxAnisotropy) F(compareFunc) F(compareMode) F(borderColor) F(borderColorI) \
+    F(borderColorUI) F(borderColorForm)
+
 #define MGP_FIELDS_PerBufferBlendState(F) \
     F(Enabled) F(SrcFactorRGB) F(DstFactorRGB) F(SrcFactorAlpha) F(DstFactorAlpha) F(ColorEquation) \
     F(AlphaEquation)
@@ -326,7 +354,8 @@
     P(MGPDrawRange) P(MGPDrawIndirect) P(MGPGridInfo) P(MGPMemoryBarrier) P(MGPStreamOutputBegin) \
     P(MGPXfbAccounting) P(MGPStreamOutputControl) P(MGPFlush) P(MGPPresent) P(MGPSwapInterval) \
     P(MGPSurfaceInfo) \
-    P(RenderStateParameters) P(PixelStoreParameters) P(PerBufferBlendState) P(StencilFaceState) \
+    P(RenderStateParameters) P(PixelStoreParameters) P(SamplerParameters) P(PerBufferBlendState) \
+    P(StencilFaceState) \
     P(DynamicBackendParameters) P(MGHostSpan) \
     P(MGPVertexAttribWire) P(MGPVertexBindingPointWire)
 

MobileGL/MG_Pipe/PipeMutation.h

@@ -56,7 +56,11 @@ namespace MobileGL::MG_Pipe {
     enum class MGPipeAggregate : Uint32 {
         // VertexArrayState: any VAO attribute format / buffer / enable moved.
         VaoAttribute = 0,
-        // FramebufferState: any FBO attachment or default-geometry write, or a bind.
+        // FramebufferState: any FBO attachment or default-geometry write, or a bind - and, since
+        // P4a (fable seam F-3), any STORAGE DEFINITION of a texture or a renderbuffer, because
+        // set_framebuffer_state inlines an attachment's format, extent and samples and those
+        // setters are the only writers of what it inlines (TextureObject.cpp /
+        // RenderbufferObject.cpp, PipePublishDescriptor).
         FramebufferAttachment,
         // TextureState: any texture object CONTENT moved (an upload, a dirty region).
         TextureContent,
@@ -94,6 +98,15 @@ namespace MobileGL::MG_Pipe {
 
 namespace MobileGL::MG_State::GLState {
     class BufferObject;
+    // P4a's five, for the BIRTH half at the tail of this header. Declarations only, exactly as
+    // BufferObject is: none of the hooks below needs a definition, and this header must not
+    // gain one - reaching a frontend class header from here would put the state machine's own
+    // types in front of every mutator that spells MGP_NOTE_MUTATION.
+    class ITextureObject;
+    class RenderbufferObject;
+    class FramebufferObject;
+    class SamplerObject;
+    class ProgramObject;
 }
 
 namespace MobileGL::MG_Pipe {
@@ -140,6 +153,66 @@ namespace MobileGL::MG_Pipe {
     // is asked rather than assumed.
     Bool MGPipeEmitVertexElementsDestroyAndFree(Uint64 lifetimeId);
 
+    // ---- P4a: ONE CLIENT-SIDE DEATH HELPER PER KIND P4a MINTS (brief D-I1) ----
+    //
+    // BACKEND-NEUTRAL FROM DAY ONE, and this is the P3a final-review lesson taken forward
+    // rather than repeated. Before it, the only thing that ever returned a VertexElementsCso
+    // slot was DirectGLES' StateObjectDeathOps table; under a backend that installs none -
+    // DirectVulkan/Magma, which keeps its own age-reclaimed identity table on purpose - every
+    // VAO ever created held its slot and its applier record for the life of the process, and
+    // past 65536 slots every create became a permanent Fatal{ProtocolCorruption}. P4a mints
+    // SIX kinds, so the rule is stated once and obeyed six times: whatever mints a handle owns
+    // the death of that handle, the client mints all six, and a backend death notice is a
+    // redundant SECOND path that must be idempotent - which it is, because it resolves through
+    // the same lifetimeId -> slot map these free, and MGPipeSlotAllocator::Free refuses a slot
+    // that is not live at that generation.
+    //
+    // THE ORDER INSIDE EACH IS FIXED AND IS NOT A PACKAGE'S CHOICE:
+    //   1. emit the wire delete FIRST - it drops the applier's record while the record still
+    //      exists, so a recycled slot cannot inherit a field;
+    //   2. raise NotifyStateObjectDestroyed SECOND - it resolves the handle through the
+    //      allocator, and a backend told after the Free could no longer find its twin, which
+    //      moves the leak from the client to the driver object;
+    //   3. free the slot LAST, and a double free on a stale generation is a proven no-op
+    //      because Free bumps no generation (the bump rides the next handout).
+    //
+    // ALL SIX TAKE THE LIFETIME ID rather than the object, for MGPipeEmitVertexElementsDestroy
+    // AndFree's reason: they run from a destructor, where the last SharedPtr has already
+    // dropped, and the lifetime id is what the slot allocator resolves the handle from. It is
+    // also what keeps this header a declaration-only coupling - no frontend class needs
+    // forward-declaring for any of them.
+    //
+    // Each returns whether its wire delete actually went out, which is the LATCH taken at the
+    // object's create and not a second reading of the subsystem predicate: an object born
+    // while a subsystem bit was clear and destroyed after it was set would otherwise free its
+    // slot with the applier's record still Live, on a slot about to be handed out again. The
+    // legacy path runs only when the answer is false.
+
+    // ResourceDestroy, and then the SamplerViewCso minted off this same lifetime id (P4a
+    // D-F2: one sampler view per ITextureObject). Called from TextureObjectBase's VIRTUAL
+    // destructor, so 2D / 3D / cube / buffer / view all announce exactly once.
+    Bool MGPipeEmitTextureDestroyAndFree(Uint64 lifetimeId);
+    // ResourceDestroy.
+    Bool MGPipeEmitRenderbufferDestroyAndFree(Uint64 lifetimeId);
+    // NO WIRE CALL AT ALL (D-I2). PipeCalls.def has no framebuffer delete, because a
+    // framebuffer is not a resource and is not a CSO - it is STATE, and set_framebuffer_state
+    // is the only call that names one - and the catalogue is closed, so P4a does not invent a
+    // row. The handle is minted and freed entirely client-side and this helper does steps 2
+    // and 3 only. A recycled framebuffer handle is distinguished by Gen, which is inside the
+    // record's ContentHash, so it can never be suppressed against its predecessor's record.
+    Bool MGPipeEmitFramebufferDestroyAndFree(Uint64 lifetimeId);
+    // DeleteSamplerState. Also the path the content-addressed CSO cache's LRU eviction takes,
+    // which is why it is addressed by lifetime id and not by "the object that owns it".
+    Bool MGPipeEmitSamplerCsoDestroyAndFree(Uint64 lifetimeId);
+    // DeleteSamplerView. Called by the texture helper above; a sampler view has no frontend
+    // object of its own, so this is the only path there is.
+    Bool MGPipeEmitSamplerViewCsoDestroyAndFree(Uint64 lifetimeId);
+    // DeleteShaderState, for an ordinary program AND for a program-pipeline COMPOSITE, whose
+    // slot has two independent release paths - the pipeline cache's LRU eviction and the
+    // composite ProgramObject's own destructor. One helper for both, and the second call is a
+    // proven no-op.
+    Bool MGPipeEmitShaderCsoDestroyAndFree(Uint64 lifetimeId);
+
     void MGPipeEmitResourceCreate(MG_State::GLState::BufferObject& buffer);
     void MGPipeEmitResourceRespecify(MG_State::GLState::BufferObject& buffer);
     void MGPipeEmitResourceSubData(MG_State::GLState::BufferObject& buffer, SizeT offset, SizeT size);
@@ -151,6 +224,197 @@ namespace MobileGL::MG_Pipe {
     // Returns the coherent host pointer the resource owner donated, or null for a DECLINE -
     // which is a real answer. Every call, mint or decline, is one map-persistent roundtrip.
     void* MGPipeEmitMapPersistent(MG_State::GLState::BufferObject& buffer);
+
+    // ================================================================================
+    // P4a: THE BIRTH HALF, one hook per client path MG_State owns (D-C .. D-I)
+    // ================================================================================
+    //
+    // The death helpers above are half a lifetime. The other half is emitted from MG_State
+    // too - a texture's create from its constructor, a renderbuffer's respecify from its
+    // storage mutators, a texture's params from glTexParameter*, a sampler CSO from the
+    // sampler object, a shader CSO from the program - because that is where the event
+    // happens, exactly as P3a's buffer family emits from BufferObject's own dispatchers
+    // (ARCHITECTURE.md 5.1 names those as the ONE exception to push-at-validate). Only the
+    // texture sub-data DRAIN runs at the validate point, and even it is fed from here: the
+    // drain list is appended on a level's first dirty mark.
+    //
+    // WHY THEY ARE DECLARED HERE. This header is the one door MG_State has into the client
+    // (check_include_closure.py's mutation-header probe pins it: reaching
+    // MG_Impl/Pipe/*Emit.h from a frontend mutator would pull the client's emitters into the
+    // state machine that calls them). So a hook a frontend mutator calls is DECLARED here and
+    // DEFINED in MG_Impl/Pipe/PipeFill.cpp, which is package A's for the whole phase - the
+    // same "declaration here, definition there" split MGPipeMintResourceHandle and
+    // MGPipeEmitResourceCreate use, and the reason no file is touched twice.
+    //
+    // WHAT EACH BODY DOES, and the division is fixed:
+    //   * PipeFill.cpp owns the GATE - the subsystem bit in MOBILEGL_PIPE_PUSH *and* the
+    //     family's own kMGPipeWired*Subsystem constant, the same pair the validate point's
+    //     `wants()` applies to every emission - and the four MINTS, which are pure allocator
+    //     work and need no family knowledge;
+    //   * the FAMILY EMITTER (MG_Impl/Pipe/<Family>Emit.h, owned by package B or C) owns the
+    //     payload build, the handle rule for its own kind and the PUBLICATION LATCH below.
+    //     PipeFill.cpp forwards to it through an entry point that is compiled only while that
+    //     family's wired constant is non-zero, so this tree links against the STUB emitters
+    //     and against the finished ones with no edit to PipeFill.cpp - and a family that sets
+    //     its constant without providing the entry point is a COMPILE ERROR in its own commit
+    //     rather than a surprise at the merge. The entry point each hook forwards to is named
+    //     beside it and spelled out in PipeFill.cpp's contract block.
+    //
+    // NOTHING CALLS ANY OF THEM AT THE CONTRACT COMMIT. B and C add the call sites in the
+    // five MG_State directories C.7 gives them, in the SAME commit that gives the emitter its
+    // body - by EDITING an existing constructor/mutator body, never by adding one (G1).
+
+    // ---- the publication latch (D-I1), and it is the ONE answer both halves read ----
+    //
+    // The create is gated at its call site and the destroy inside the death helper, so the
+    // two ask the same question at two different moments. An object born while its subsystem
+    // bit was clear and destroyed after it was set would otherwise free its slot with the
+    // applier's record still Live - on a slot the allocator is about to hand out again. A
+    // slot is NOT evidence of a record either: a backend twin table mints one through
+    // MGPipeSlots().Acquire whether or not the subsystem ever asked this client to emit a
+    // create, and a delete_* on such a handle is a refused call the applier asserts on.
+    //
+    // So the emitter latches the answer when its create actually goes out, the death helper
+    // reads the latch, and the latch is keyed by {kind, slot, gen} so a recycled slot cannot
+    // inherit its predecessor's answer. Defined in PipeFill.cpp beside the six death helpers,
+    // declared here because both the helpers and the five emit headers read it.
+    void MGPipeNoteHandlePublished(MGPipeKind kind, MGPipeHandle handle);
+    Bool MGPipeHandleIsPublished(MGPipeKind kind, MGPipeHandle handle);
+    void MGPipeNoteHandleUnpublished(MGPipeKind kind, MGPipeHandle handle);
+
+    // ---- the four mints (pure allocator work, no family knowledge) ----
+    //
+    // UNCONDITIONAL in a push build, for MGPipeMintResourceHandle's reason: a handle is CLIENT
+    // state and other subsystems name these objects by handle whether or not their own family
+    // is switched on - MGPSurface::Res names a Texture or a Renderbuffer out of the framebuffer
+    // subsystem, MGPBoundView::Texture and MGPImageView::Res name a Texture out of the sampler
+    // one. Gating the mint on the family bit would make those emit null handles in exactly the
+    // A/B arm that exists to isolate the families. Each costs one free-list pop and one map
+    // insert per object and emits nothing.
+    void MGPipeMintTextureHandle(MG_State::GLState::ITextureObject& texture);
+    void MGPipeMintRenderbufferHandle(MG_State::GLState::RenderbufferObject& renderbuffer);
+    // A framebuffer has a handle and NO wire lifetime (D-I2): set_framebuffer_state is the only
+    // call that names one, and there is no create or destroy for the kind. The mint is still
+    // the object's, so the identity exists before the first validate point that pushes it.
+    void MGPipeMintFramebufferHandle(MG_State::GLState::FramebufferObject& framebuffer);
+    // Ordinary programs only. A program-pipeline COMPOSITE is minted by the composite resolver
+    // out of the reserved band through MGPipeSlotAllocator::AllocateComposite, which is the one
+    // door into it, and it is not a frontend construction event.
+    void MGPipeMintShaderCsoHandle(MG_State::GLState::ProgramObject& program);
+
+    // ---- textures and renderbuffers: MG_Impl/Pipe/TextureEmit.h, package B ----
+    //
+    // resource_create from ITextureObject's constructor and RenderbufferObject's;
+    // resource_respecify from every storage-defining entry point, including
+    // RenderbufferObject::{SetInternalFormat, AllocateStorage, SetSamples}, which publish
+    // nothing at all today (D-D2); set_texture_params from the parameter mutators, which is
+    // where the READ-attachment-only gap D-E3 closes.
+    //
+    // Entry points MGPipeTextureEmitter must provide, all taking the frontend object by
+    // reference and returning void:
+    //   EmitResourceCreate(ITextureObject&)
+    //   EmitResourceRespecify(ITextureObject&, MGPipeTextureRespecifyScope, Uint32 uploadTarget,
+    //                         Uint32 level)
+    //   EmitTextureParams(ITextureObject&)
+    //   NoteLevelDirty(ITextureObject& storageOwner, Uint32 uploadTarget, Uint32 level)
+    //   EmitRenderbufferCreate(RenderbufferObject&) / EmitRenderbufferRespecify(RenderbufferObject&)
+    void MGPipeEmitTextureResourceCreate(MG_State::GLState::ITextureObject& texture);
+
+    // WHICH STORAGE A TEXTURE RESPECIFY REPLACES (P4a final review C-1). The applier scopes
+    // its pending-upload clear on this answer and not on the descriptor, because the
+    // descriptor cannot give it: AllocateStorage is per (uploadTarget, level) and
+    // TruncateMipmapLevels removes every level at or above a cut, while MGPResourceDesc
+    // carries only the base extent and the level count. A level the applier had ACCEPTED at
+    // one verb (the client's dirty flag already clear, D-D5 step 1) and that a later per-level
+    // definition redefined AROUND was dropped by the whole-resource arm with nobody owing its
+    // texels - so every respecify states its scope, and "whole resource" is said, never
+    // defaulted. The emitter builds wire's MGPRespecifiedLevel from the pair, packed exactly
+    // as the drain packs a sub-data record's Target (MGPipePackSubDataTarget), so the key it
+    // drops is the key that level's emission made.
+    enum class MGPipeTextureRespecifyScope : Uint32 {
+        // The whole store is redefined or restated: a format, sample-count or
+        // fixed-sample-locations change, an immutable allocation completing
+        // (SetImmutableLevels), a texture view's creation. Every pending upload goes.
+        WholeResource = 0,
+        // ONE (uploadTarget, level) was (re)allocated: glTexImage*D, glCompressedTexImage*D,
+        // glCopyTexImage*D, one level of a glTexStorage* loop, one level of a generated-mipmap
+        // grow. That level's pending upload goes; every other level's stays. `uploadTarget` and
+        // `level` name it.
+        OneLevel = 1,
+        // The chain was cut: every level of `uploadTarget` at or above `level` is gone and the
+        // levels below it are untouched (glGenerateMipmap fitting the chain, a base-level
+        // redefinition discarding its tail, glTexStorage* fitting the chain to its level
+        // count). `level` is the first level removed; a cut at 0 is the whole resource.
+        LevelsFrom = 2,
+    };
+    void MGPipeEmitTextureResourceRespecify(MG_State::GLState::ITextureObject& texture,
+                                            MGPipeTextureRespecifyScope scope, Uint32 uploadTarget,
+                                            Uint32 level);
+    void MGPipeEmitTextureParams(MG_State::GLState::ITextureObject& texture);
+    // The DRAIN LIST's append, on a level's FIRST dirty mark, keyed on the STORAGE OWNER from
+    // day one (D-D4: a view and its owner already share one dirty state, so an upload through
+    // either lands on the same key). The record itself is emitted at the validate point by
+    // MGPipeTextureEmitter::DrainTextureSubData; this is only what puts the level on the list,
+    // and walking every live texture per verb is the cost it exists to avoid.
+    void MGPipeNoteTextureLevelDirty(MG_State::GLState::ITextureObject& storageOwner, Uint32 uploadTarget,
+                                     Uint32 level);
+    void MGPipeEmitRenderbufferResourceCreate(MG_State::GLState::RenderbufferObject& renderbuffer);
+    void MGPipeEmitRenderbufferResourceRespecify(MG_State::GLState::RenderbufferObject& renderbuffer);
+
+    // ---- D-A4's two sticky bind-mask producers (P4a final review M-A) ----
+    //
+    // kMGPipeBindSampler is "any texture the sampler-view resolution names in an emitted
+    // MGPBoundView" and kMGPipeBindShaderImage "any texture named in an emitted MGPImageView"
+    // - both the SAMPLER package's emitters (SamplerEmit.h, ImageEmit.h), which the texture
+    // emitter's header includes and which therefore cannot include it back - and, earliest of
+    // all, glBindImageTexture's state setter (TextureState.h, MG_State), which may include no
+    // emit header at all. So the note goes through this door, exactly as the birth hooks do.
+    // Nothing produced either bit before the fix round: ImageBindableHint was always 0, the
+    // metadata respecify (ID-18 M4) had no live trigger, and the remint pull the hint exists to
+    // prevent was neither prevented nor counted.
+    //
+    // UNCONDITIONAL IN A PUSH BUILD, like the mints: the mask is CLIENT state the framebuffer
+    // emitter ORs into whether or not the texture family is on, and the emission a mask move
+    // causes (the metadata respecify) is gated inside the emitter on the family's own pair.
+    void MGPipeNoteTextureBoundAs(MGPipeHandle texture, Uint32 bindBit);
+    // glBindImageTexture. The hint is the PREVENTION half of the texture-remint stall class -
+    // a texture the server knows may be image-bound is allocated image-bindable up front - so it
+    // has to reach the applier before the texture's first sync, i.e. at the bind itself, not at
+    // the validate point's image walk (which notes it as well, D-A4's letter).
+    void MGPipeNoteTextureImageBound(MG_State::GLState::ITextureObject& texture);
+
+
+    // ---- sampler CSOs and sampler views: MG_Impl/Pipe/SamplerEmit.h, package C ----
+    //
+    // Entry points MGPipeSamplerEmitter must provide, returning void:
+    //   EmitSamplerCso(SamplerObject&)     - D-F1's content-addressed mint-or-share at
+    //                                        capacity 256, hashed field-wise over a canonical
+    //                                        zero-initialised copy, behind the version-first
+    //                                        skip. The HANDLE RULE FOR THIS KIND IS THE
+    //                                        EMITTER'S, not this file's: two identical
+    //                                        samplers share one CSO, so there is deliberately
+    //                                        no per-object mint above, and it is the emitter
+    //                                        that decides which lifetime id (if any) owns the
+    //                                        slot the death helper will resolve.
+    //   EmitSamplerView(ITextureObject&)   - D-F2's ONE view per texture object, minted off
+    //                                        the texture's own lifetime id and re-issued on
+    //                                        the SAME handle when the restrictions move.
+    void MGPipeEmitSamplerCsoCreate(MG_State::GLState::SamplerObject& sampler);
+    void MGPipeEmitSamplerViewCreate(MG_State::GLState::ITextureObject& texture);
+
+    // ---- programs: MG_Impl/Pipe/ProgramEmit.h, package C ----
+    //
+    // Entry point MGPipeProgramEmitter must provide, returning void:
+    //   EmitShaderCso(ProgramObject&)
+    //
+    // Re-issued on the SAME handle whenever the link version moves, exactly as
+    // create_vertex_elements is (Gen moves only on slot reuse). D-H4 keeps the TRACKER out of
+    // it - bit 6's shutter reads GetCurrentProgram() and deliberately not GetProgramForDraw(),
+    // because the tracker must not force a compile to answer "did the shader move" - so the
+    // ordinary emission is the validate point's, from the join the verb was going to make
+    // anyway. This hook exists for the paths that are NOT a draw: a link that completes off
+    // the draw path still owns its own publication.
+    void MGPipeEmitShaderCsoCreate(MG_State::GLState::ProgramObject& program);
 } // namespace MobileGL::MG_Pipe
 #define MGP_NOTE_MUTATION(Field)                                                                                       \
     ::MobileGL::MG_Pipe::MGPipeNoteFrontendMutation(::MobileGL::MG_Pipe::MGPipeInputField::Field)

MobileGL/MG_Pipe/generated/PipeFilled.inc

@@ -308,8 +308,13 @@ enum class MGPipeFieldEmitter : Uint8 {
     BindRenderState,
     BindVertexElements,
     CreateRenderState,
+    SetDispatchProgram,
+    SetDrawProgram,
     SetDynamicState,
+    SetFramebufferState,
     SetPatchState,
+    SetSamplerViews,
+    SetShaderImages,
     SetVertexAttribDefaults,
 };
 
@@ -318,8 +323,13 @@ inline constexpr const char* kMGPipeFieldEmitterNames[] = {
     "BindRenderState",
     "BindVertexElements",
     "CreateRenderState",
+    "SetDispatchProgram",
+    "SetDrawProgram",
     "SetDynamicState",
+    "SetFramebufferState",
     "SetPatchState",
+    "SetSamplerViews",
+    "SetShaderImages",
     "SetVertexAttribDefaults",
 };
 
@@ -344,11 +354,11 @@ inline constexpr MGPipeFieldEmitter kMGPipeFieldEmittedBy[kMGPipeInputFieldCount
     MGPipeFieldEmitter::CreateRenderState, // GetDepthFunc
     MGPipeFieldEmitter::CreateRenderState, // GetDepthMask
     MGPipeFieldEmitter::SetDynamicState, // GetDepthRangeIndexed
-    MGPipeFieldEmitter::kNone, // GetFramebufferBindingSlot
-    MGPipeFieldEmitter::kNone, // GetImageTextureBinding
+    MGPipeFieldEmitter::SetFramebufferState, // GetFramebufferBindingSlot
+    MGPipeFieldEmitter::SetShaderImages, // GetImageTextureBinding
     MGPipeFieldEmitter::SetDynamicState, // GetLineWidth
     MGPipeFieldEmitter::CreateRenderState, // GetLogicOp
-    MGPipeFieldEmitter::kNone, // GetMaxTouchedTextureUnit
+    MGPipeFieldEmitter::SetSamplerViews, // GetMaxTouchedTextureUnit
     MGPipeFieldEmitter::CreateRenderState, // GetMinSampleShadingValue
     MGPipeFieldEmitter::SetPatchState, // GetPatchDefaultInnerLevel
     MGPipeFieldEmitter::SetPatchState, // GetPatchDefaultOuterLevel
@@ -359,8 +369,8 @@ inline constexpr MGPipeFieldEmitter kMGPipeFieldEmittedBy[kMGPipeInputFieldCount
     MGPipeFieldEmitter::SetDynamicState, // GetPolygonOffsetFactor
     MGPipeFieldEmitter::SetDynamicState, // GetPolygonOffsetUnits
     MGPipeFieldEmitter::SetDynamicState, // GetPrimitiveRestartIndex
-    MGPipeFieldEmitter::kNone, // GetProgramForDispatch
-    MGPipeFieldEmitter::kNone, // GetProgramForDraw
+    MGPipeFieldEmitter::SetDispatchProgram, // GetProgramForDispatch
+    MGPipeFieldEmitter::SetDrawProgram, // GetProgramForDraw
     MGPipeFieldEmitter::kNone, // GetProgramObject
     MGPipeFieldEmitter::CreateRenderState, // GetProvokingVertexMode
     MGPipeFieldEmitter::CreateRenderState, // GetRenderStateParameters
@@ -371,7 +381,7 @@ inline constexpr MGPipeFieldEmitter kMGPipeFieldEmittedBy[kMGPipeInputFieldCount
     MGPipeFieldEmitter::kNone, // GetTextureBindGeneration
     MGPipeFieldEmitter::kNone, // GetTextureContextId
     MGPipeFieldEmitter::kNone, // GetTextureObject
-    MGPipeFieldEmitter::kNone, // GetTextureUnitObject
+    MGPipeFieldEmitter::SetSamplerViews, // GetTextureUnitObject
     MGPipeFieldEmitter::kNone, // GetTransformFeedbackCapturedVertices
     MGPipeFieldEmitter::kNone, // GetTransformFeedbackGeneration
     MGPipeFieldEmitter::kNone, // GetTransformFeedbackPausedPrimitiveCounter
@@ -388,7 +398,7 @@ inline constexpr MGPipeFieldEmitter kMGPipeFieldEmittedBy[kMGPipeInputFieldCount
     MGPipeFieldEmitter::kNone, // GetBoundTransformFeedbackLifetimeId
     MGPipeFieldEmitter::kNone, // HasOpenTransformFeedbackSpan
 };
-inline constexpr SizeT kMGPipeEmittedFieldCount = 34;
+inline constexpr SizeT kMGPipeEmittedFieldCount = 40;
 
 struct MGPipeFilledState {
     Uint64 CurrentVerbSerial;

MobileGL/MG_Pipe/generated/PipeVerify.inc

@@ -109,6 +109,7 @@ inline Bool MGPipeVerify(const MGPSwapInterval& a, const MGPSwapInterval& b, con
 inline Bool MGPipeVerify(const MGPSurfaceInfo& a, const MGPSurfaceInfo& b, const char** outField);
 inline Bool MGPipeVerify(const RenderStateParameters& a, const RenderStateParameters& b, const char** outField);
 inline Bool MGPipeVerify(const PixelStoreParameters& a, const PixelStoreParameters& b, const char** outField);
+inline Bool MGPipeVerify(const SamplerParameters& a, const SamplerParameters& b, const char** outField);
 inline Bool MGPipeVerify(const PerBufferBlendState& a, const PerBufferBlendState& b, const char** outField);
 inline Bool MGPipeVerify(const StencilFaceState& a, const StencilFaceState& b, const char** outField);
 inline Bool MGPipeVerify(const DynamicBackendParameters& a, const DynamicBackendParameters& b, const char** outField);
@@ -247,6 +248,8 @@ struct MGPipeHasFieldVerifier<RenderStateParameters> : std::true_type {};
 template <>
 struct MGPipeHasFieldVerifier<PixelStoreParameters> : std::true_type {};
 template <>
+struct MGPipeHasFieldVerifier<SamplerParameters> : std::true_type {};
+template <>
 struct MGPipeHasFieldVerifier<PerBufferBlendState> : std::true_type {};
 template <>
 struct MGPipeHasFieldVerifier<StencilFaceState> : std::true_type {};
@@ -629,6 +632,11 @@ inline Bool MGPipeVerify(const PixelStoreParameters& a, const PixelStoreParamete
     return true;
 }
 
+inline Bool MGPipeVerify(const SamplerParameters& a, const SamplerParameters& b, const char** outField) {
+    MGP_FIELDS_SamplerParameters(MGP_VERIFY_FIELD)
+    return true;
+}
+
 inline Bool MGPipeVerify(const PerBufferBlendState& a, const PerBufferBlendState& b, const char** outField) {
     MGP_FIELDS_PerBufferBlendState(MGP_VERIFY_FIELD)
     return true;
@@ -661,4 +669,4 @@ inline Bool MGPipeVerify(const MGPVertexBindingPointWire& a, const MGPVertexBind
 
 #undef MGP_VERIFY_FIELD
 
-inline constexpr SizeT kMGPipeVerifiedPayloadCount = 71;
+inline constexpr SizeT kMGPipeVerifiedPayloadCount = 72;

MobileGL/MG_Pipe/generated/PipeWire.inc

@@ -118,6 +118,127 @@ enum class MGPWireOp : Uint16 {
     kOpCount = 72,
 };
 
+// THE FLAGS, EXPORTED ONCE, INDEXED BY OPCODE (P5 R-13.4). MGPWireRecHeader::Flags is
+// documented as "MGPipeCallFlags of the call", and until this table existed nothing
+// generated said what those were: every consumer that needed to know whether a record owns
+// an MGPBlobRef, a variable tail or a reply slot had to hard-code its own copy of
+// PipeCalls.def's fourth column, and six of them were about to. A hard-coded copy is how
+// GetCaps and CreateSamplerState came to carry an MGPBlobRef member with no kHasBlob on
+// their line at all - nothing compared the two, because nothing had both in one place.
+//
+// Index 0 is MGPWireOp::kInvalid and is kNone: the catalogue is 1-based, and an encoder
+// that reads flags for an opcode it never got from the catalogue must see the empty set
+// rather than another call's flags.
+//
+// kHasBlob here means EXACTLY "the payload owns an MGPBlobRef member". Three calls carry
+// bytes without one - resource_respecify, resource_flush_range and map_persistent, whose
+// companion pointers have no carrier - and they are deliberately NOT flagged; MG_Remote's
+// CONTRACT-P5.md table 1 is where those live, because a decoder that trusts kHasBlob has
+// to find a member to read.
+inline constexpr Uint32 kMGPipeCallFlags[static_cast<SizeT>(MGPWireOp::kOpCount)] = {
+    /*  0 kInvalid                */ static_cast<Uint32>(kNone),
+    /*  1 GetCaps                 */ static_cast<Uint32>(kReplySlot | kHasBlob),
+    /*  2 ResourceCreate          */ static_cast<Uint32>(kNone),
+    /*  3 ResourceRespecify       */ static_cast<Uint32>(kNeedsAck),
+    /*  4 ResourceDestroy         */ static_cast<Uint32>(kNone),
+    /*  5 MapPersistent           */ static_cast<Uint32>(kReplySlot | kOptional),
+    /*  6 UnmapPersistent         */ static_cast<Uint32>(kOptional),
+    /*  7 FenceCreate             */ static_cast<Uint32>(kNone),
+    /*  8 FenceStatus             */ static_cast<Uint32>(kReplySlot),
+    /*  9 FenceWait               */ static_cast<Uint32>(kReplySlot),
+    /* 10 FenceDestroy            */ static_cast<Uint32>(kNone),
+    /* 11 QueryCreate             */ static_cast<Uint32>(kNone),
+    /* 12 QueryBegin              */ static_cast<Uint32>(kNone),
+    /* 13 QueryEnd                */ static_cast<Uint32>(kNone),
+    /* 14 QueryAvailable          */ static_cast<Uint32>(kReplySlot),
+    /* 15 QueryResult             */ static_cast<Uint32>(kReplySlot),
+    /* 16 QueryDestroy            */ static_cast<Uint32>(kNone),
+    /* 17 CreateRenderState       */ static_cast<Uint32>(kHasBlob),
+    /* 18 BindRenderState         */ static_cast<Uint32>(kNone),
+    /* 19 DeleteRenderState       */ static_cast<Uint32>(kNone),
+    /* 20 CreateVertexElements    */ static_cast<Uint32>(kHasBlob),
+    /* 21 BindVertexElements      */ static_cast<Uint32>(kNone),
+    /* 22 DeleteVertexElements    */ static_cast<Uint32>(kNone),
+    /* 23 CreateSamplerState      */ static_cast<Uint32>(kHasBlob),
+    /* 24 DeleteSamplerState      */ static_cast<Uint32>(kNone),
+    /* 25 CreateSamplerView       */ static_cast<Uint32>(kNone),
+    /* 26 DeleteSamplerView       */ static_cast<Uint32>(kNone),
+    /* 27 CreateShaderState       */ static_cast<Uint32>(kHasBlob),
+    /* 28 BindShaderState         */ static_cast<Uint32>(kNone),
+    /* 29 DeleteShaderState       */ static_cast<Uint32>(kNone),
+    /* 30 SetDynamicState         */ static_cast<Uint32>(kHasBlob),
+    /* 31 SetFramebufferState     */ static_cast<Uint32>(kNone),
+    /* 32 SetVertexBuffers        */ static_cast<Uint32>(kVarTail),
+    /* 33 SetIndexBuffer          */ static_cast<Uint32>(kNone),
+    /* 34 SetIndirectBuffers      */ static_cast<Uint32>(kNone),
+    /* 35 SetSamplerViews         */ static_cast<Uint32>(kVarTail),
+    /* 36 BindSamplerStates       */ static_cast<Uint32>(kVarTail),
+    /* 37 SetShaderImages         */ static_cast<Uint32>(kVarTail),
+    /* 38 SetShaderBuffers        */ static_cast<Uint32>(kVarTail | kHostSpan),
+    /* 39 SetStreamOutputTargets  */ static_cast<Uint32>(kVarTail),
+    /* 40 SetGlobalConstants      */ static_cast<Uint32>(kHasBlob),
+    /* 41 SetVertexAttribDefaults */ static_cast<Uint32>(kVarTail),
+    /* 42 SetPixelPackState       */ static_cast<Uint32>(kNone),
+    /* 43 SetPatchState           */ static_cast<Uint32>(kNone),
+    /* 44 SetDrawProgram          */ static_cast<Uint32>(kNone),
+    /* 45 SetDispatchProgram      */ static_cast<Uint32>(kNone),
+    /* 46 SetResidualValueState   */ static_cast<Uint32>(kHasBlob),
+    /* 47 SetTextureParams        */ static_cast<Uint32>(kNone),
+    /* 48 ResourceSubData         */ static_cast<Uint32>(kHasBlob | kVarTail),
+    /* 49 BufferSubDataResident   */ static_cast<Uint32>(kHasBlob | kOptional),
+    /* 50 ResourceSubDataComplete */ static_cast<Uint32>(kNone),
+    /* 51 ResourceFlushRange      */ static_cast<Uint32>(kNone),
+    /* 52 ResourceReadback        */ static_cast<Uint32>(kReplySlot),
+    /* 53 ResourceCopyRegion      */ static_cast<Uint32>(kNone),
+    /* 54 GenerateMipmap          */ static_cast<Uint32>(kNone),
+    /* 55 GetTextureImage         */ static_cast<Uint32>(kReplySlot),
+    /* 56 Blit                    */ static_cast<Uint32>(kNone),
+    /* 57 Clear                   */ static_cast<Uint32>(kNone),
+    /* 58 ReadPixels              */ static_cast<Uint32>(kReplySlot),
+    /* 59 DrawVbo                 */ static_cast<Uint32>(kHostSpan | kVarTail),
+    /* 60 LaunchGrid              */ static_cast<Uint32>(kNone),
+    /* 61 MemoryBarrier           */ static_cast<Uint32>(kNone),
+    /* 62 BeginStreamOutput       */ static_cast<Uint32>(kNone),
+    /* 63 EndStreamOutput         */ static_cast<Uint32>(kNone),
+    /* 64 PauseStreamOutput       */ static_cast<Uint32>(kNone),
+    /* 65 ResumeStreamOutput      */ static_cast<Uint32>(kNone),
+    /* 66 Flush                   */ static_cast<Uint32>(kNone),
+    /* 67 Present                 */ static_cast<Uint32>(kNone),
+    /* 68 SetSwapInterval         */ static_cast<Uint32>(kOptional),
+    /* 69 QueryTimestamp          */ static_cast<Uint32>(kReplySlot),
+    /* 70 QueryCounter            */ static_cast<Uint32>(kNone),
+    /* 71 FenceWaitServer         */ static_cast<Uint32>(kNone),
+};
+static_assert(sizeof(kMGPipeCallFlags) / sizeof(kMGPipeCallFlags[0]) ==
+                  static_cast<SizeT>(MGPWireOp::kOpCount),
+              "the flags table and the opcode space disagree");
+
+// The only supported read of the table. Out-of-range is kNone rather than undefined
+// behaviour, because the one caller that can pass a bad opcode is a decoder holding bytes
+// off a stream, and it must reach its own Fatal{ProtocolCorruption} rather than read past
+// the array on the way there.
+inline constexpr Uint32 MGPipeCallFlagsFor(MGPWireOp op) {
+    const SizeT index = static_cast<SizeT>(op);
+    return index < static_cast<SizeT>(MGPWireOp::kOpCount) ? kMGPipeCallFlags[index]
+                                                           : static_cast<Uint32>(kNone);
+}
+
+// Spot checks the generator states about its own output, so that a catalogue edit that
+// silently drops a flag is a build break here and not a wrong decode six packages away.
+static_assert(MGPipeCallFlagsFor(MGPWireOp::kInvalid) == static_cast<Uint32>(kNone),
+              "opcode 0 is not a call and carries no flags");
+static_assert((MGPipeCallFlagsFor(MGPWireOp::GetCaps) & static_cast<Uint32>(kHasBlob)) != 0,
+              "MGPCaps owns two MGPBlobRef members; R-13.1 gave the call its flag");
+static_assert((MGPipeCallFlagsFor(MGPWireOp::CreateSamplerState) & static_cast<Uint32>(kHasBlob)) != 0,
+              "MGPSamplerDesc owns an MGPBlobRef member; R-13.1 gave the call its flag");
+static_assert((MGPipeCallFlagsFor(MGPWireOp::ResourceFlushRange) & static_cast<Uint32>(kHasBlob)) == 0,
+              "R-13.2: resource_flush_range carries no bytes on the wire and owns no blobref");
+static_assert((MGPipeCallFlagsFor(MGPWireOp::ResourceRespecify) & static_cast<Uint32>(kHasBlob)) == 0,
+              "R-13.3: initial bytes follow as resource_subdata; MGPResourceDesc owns no blobref");
+static_assert((MGPipeCallFlagsFor(MGPWireOp::DrawVbo) &
+               static_cast<Uint32>(kHostSpan | kVarTail)) == static_cast<Uint32>(kHostSpan | kVarTail),
+              "draw_vbo is the conditional-tail plus host-span shape the codec is measured on");
+
 struct alignas(8) MGPWireRec_GetCaps {
     MGPWireRecHeader Header;
     MGPCaps Payload;

MobileGL/MG_Remote/CONTRACT-P5.md

@@ -0,0 +1,575 @@
+# CONTRACT-P5 — the four tables every P5 package is held to
+
+Authority: this file. `~/w7/notes/p5/BRIEF-P5.md` states the rulings R-1…R-14; this file is
+where they become implementable, and where the rulings the brief left to the contract package
+are made. Where the two disagree, this file is newer and this file wins — and §6 lists every
+place they disagree, so nobody has to diff them.
+
+**How to change it.** `MG_Remote/CONTRACT-P5.md` is c0's file. A package that needs a row
+changed goes through the integrator, who edits here first and only then lets the package land.
+P4a's contract was corrected seven times and each correction cost a package a rework round;
+the point of this file existing at all is that a correction is a one-line diff here rather than
+a rediscovery in six places.
+
+It lives beside the code, not in `~/w7/notes/`, because it describes bytes on a wire and has to
+move with the branch that defines them.
+
+Base: `feat/disaggregated @ a29807cc`. Every `file:line` below was read at that commit.
+
+---
+
+## §0 The three rules that sit above every table
+
+These are R-2 and R-11 in their formal wording. They apply to every row of table 1 without
+restatement, and every reviewer's first three questions (BRIEF §11.1, §11.4) are these three.
+
+**Rule A — a content record must declare its bytes.** Under
+`MG_Config::Transport != Monolith`, a record whose payload owns an `MGPBlobRef` and which
+carries content must set `Seg` to a real segment, `Offset` to a byte offset **within that
+segment**, and `Size` to a **non-zero** byte count. `Blob.Size == 0` on such a record is
+`Fatal{ProtocolCorruption}`.
+
+This inverts today's legal state, and deliberately. `MGPipeTypes.h:398-410` says in so many
+words that a zero `Blob.Size` means *"this record does not declare its blob"* and *"is not a
+fault"* — which is right for monolith, where the bytes travel beside the record as a companion
+pointer. Under split there is no beside.
+
+**Rule B — no host pointer crosses.** Under split, `MGHostSpan::Ptr` is written `nullptr` by
+the encoder and any non-null `Ptr` seen by the apply side is `Fatal{ProtocolCorruption}`.
+Today `Ptr` is the fast path (`MGPipeHostSpan.h:51`), which is exactly why this needs saying.
+P5's reduced path should produce **zero** host spans at all — see table 0's cap-bit row.
+
+**Rule C — an applier entry point may not hold a pointer past its return.** A `SEG_STAGE` run
+is valid from publish until `retiredSeq` passes the record that named it. The tree has exactly
+one violation and it is named rather than tolerated: Espryt's `GLESBufferResource::hostBytes`
+(`Managers.h:839`), written by `Ops_H_SubData` (`Managers.cpp:1980-1983`) and `Ops_H_FlushRange`
+(`:2035`), read by six later drains (`:2000`, `:2062`, `:2080`, `:2111`, `:2741`, `:2843`).
+Under split those two writes must **copy into server-owned storage**. `MOBILEGL_IPC_AUDIT=1`'s
+`0xDD` fill over retired staging bytes (R-2.5) is the mechanical control that says whether they
+did; without it, an `inproc` implementation that kept the pointer is indistinguishable from one
+that copied.
+
+---
+
+## §1 Table 0 — the encoding table
+
+One row per wire field that is **not a handle**. Handles are `{slot, gen}` and are settled by
+P2/P3a; everything else that is not a plain scalar is here.
+
+| field | the ruling | zero means | who reads it | evidence / note |
+|---|---|---|---|---|
+| **segment id space** | `SEG_CMD=1, SEG_STAGE=2, SEG_REPLY=3, SEG_EVENT=4, SEG_SHADOW=5, SEG_ADOPT=6`. Identical values to `Protocol::SegmentKind`. | **"no segment", always.** 0 is never a real segment id. | encoder, decoder, `gMGPipeSegmentResolver` | `protocol.fbs:36-44`; `kMGHostSpanSegNone = 0` at `MGPipeHostSpan.h:21`. The two are tied by `static_assert` in `Wire/PipeWireCodec.cpp`, which is the only place the flatbuffers header and the codec enum meet. `kMGHostSpanSegFromServerIndexMirror = 0xFFFFFFFF` (`:26`) stays reserved for P8. |
+| **`MGPBlobRef{Offset, Size, Seg, Pad0}`** (24 B, `MGPipeTypes.h:55-61`) | `Seg` from the row above. `Offset` is a **byte offset inside that segment**, never a host address. `Size != 0` ⇔ "this record declares its blob", and under split a content record **must** declare it (rule A). | `Size == 0` = "no blob declared" — legal in monolith, `Fatal` under split for a content record. | decoder, every bounds cross-check | Today every emitter writes `{Seg=None, Offset=<host address>, Size=0 or real}`. Five of the eleven blob members do declare a real size today (`CsoCache.h:156`, `VertexInputEmit.h:398`, `ResourceTracker.h:216`, `PipeFill.cpp:2259`); the rest write 0. See table 1's "length" column for which. |
+| **`MGHostSpan{Ptr, Seg, Pad0, Size, Offset}`** (32 B, `MGPipeHostSpan.h:28-37`) | Split: `Ptr == nullptr` always (rule B). **The 32-byte layout must not be reordered** (`:29-31`). | `Seg == 0` with `Size != 0` is `Fatal`. | decoder | **P5's reduced path must produce none at all.** See the cap-bit row below. |
+| **`kCapNeedsHostIndexBytes` (1<<7), `kCapNeedsHostUboBytes` (1<<8)** | **Both are 0 for the whole of P5**, by ruling. | — | client emitters | `MGPipeTypes.h:120-123`. This is the cheapest way to keep every `MGHostSpan` out of the first IPC frame: the two bits are the only things that ask for one. `TriangleScenario` must therefore use a **VBO-backed draw and not client-array indices**, or `kDrawHasUserIndices` (`MGPipeTypes.h:1212`) produces a span the split filling for which is P8's. |
+| **`MGPCaps`** (4 members, `MGPipeTypes.h:126-139`) | **One carrier, not two.** `MGPCaps` is the model; `protocol.fbs`'s `CapsSnapshot` is its transport form. `Dynamic` and `CallMask` cross as POD bytes; `FormatCapabilities` and `RendererInfo` cross as the two blobs whose serializers are P5's new work (`MG_Remote/CapsCodec.h`). | — | `CapsMirror` (client), `ServerSession` (server) | `MGPCaps` has only a **compositional** size assertion (`MGPipeTypes.h:145-146`) because `DynamicBackendParameters` still carries `SizeT` and `GLenum`; P0.5's fixed-width rewrite never happened. **P5 does not rewrite it** — see the ABI row. |
+| **`CapsSnapshot` redundancy** | `tableSlotMask` (`protocol.fbs:94`) is **DELETED**, not renamed. `maxComputeWorkGroupCount` / `maxComputeWorkGroupSize` (`:92-93`) and `prefersCpuXfbPrimitiveAccounting` (`:95`) are **deleted** too: the first two ride inside `Dynamic` already (`BackendObject.h:392-393`), and the third is answered by `kCapCpuXfbPrimitiveAccounting`. | — | s1 (the schema), c1 (the mirror) | R-8 offered rename-or-delete for `tableSlotMask`; **delete**, for two reasons and the second is decisive. `ARCHITECTURE.md:114` says `CallMask` *replaces* "is this table slot null" as the capability probe, so a field whose comment is "which `GLFunctionsTable` slots the peer registered" re-introduces precisely what it replaced. And `GLFunctionsTable` has **69** function-pointer slots (`BackendObject.h:117-292`), so a `ulong` mask cannot address it and never could — it is five bits short on day one. |
+| **`MGPCaps::CallMask` layout** | bits **0..8** = `MGPCapBit`, unchanged. bits **9..31** reserved. bits **32..47** = the **consumer mask**: bit `32+n` means "the server has a consumer for MGPipe subsystem bit `n`". bits **48..63** reserved. | a clear consumer bit = "this server does not consume that family; emit nothing for it". | `CapsMirror::ServerConsumes` — the **only** legal client-side source | c0's ruling, and the thing that makes R-8 implementable at all: R-8 says the client's liveness gates must read the `CallMask` mirror, but `CallMask` as declared has only nine feature bits and no per-family bit. Constants and the two fold/test helpers are in `MG_Remote/CapsCodec.h`; `CapsCodec.cpp` asserts the block does not collide with `MGPCapBit` and that P4a's `0x1fff` fits sixteen bits. |
+| **ABI agreement** | `Hello`/`Welcome` assert both peers agree on `sizeof(DynamicBackendParameters)`, `sizeof(MGPCaps)`, `sizeof(GLFunctionsTable)` and `buildFingerprint`. A mismatch is `Fatal{AbiMismatch}` and **never** a downgrade. | — | s1 | The compositional assertion above means the caps block's literal size is ABI-dependent. P6's spawn is same-machine, same-binary and inherits this unchanged. A fixed-width rewrite of `DynamicBackendParameters` is **P7's** account, not P5's. |
+| **`MGPSubData::Target`** | Packed: **low byte = `MGPipeResourceTarget`, high byte = the cube-face upload target**. Read only through `MGPipeSubDataResourceTargetOf` / `MGPipeSubDataUploadTargetOf`. Whole field `== 0` is the **buffer** half; a low byte naming `Buffer`, `Renderbuffer` or `>= MGPipeResourceTarget::Count` is `Fatal{ProtocolCorruption}`. | whole field 0 = buffer upload | applier | P4a ID-12. Already settled; copied here because a decoder that open-codes it is the class-1 defect. |
+| **`MGPImageView::Access`** | The three-value encoding at `ImageEmit.h:146-159`, verbatim. | — | decoder, applier | **This encoding has only ever lived in a package header** (P4a R-3). This table is its first wire reader, so it is now contract. |
+| **`MGPSamplerView::Target`** | The encoding at `SamplerEmit.h:900`, verbatim. | — | decoder, applier | Same status as the row above. |
+| **`MGPFramebufferState::DrawBuffers[8]`** | The `-1` / default-token narrowing at `FramebufferEmit.h:146-163`, verbatim. A draw-buffer entry naming a colour attachment outside the record's own array is `Fatal{ProtocolCorruption}` (the applier already says so). | `-1` = "no attachment" | decoder, applier | Same status. |
+| **`MGPReplySlot::Id`** | **= the record's sequence number** (R-3). No new id space, no allocator. The server writes the answer into `SEG_REPLY[seq % slots]` and **stamps `seq` back into the slot header** so a wrong-slot read is detectable rather than plausible. | seq is 1-based; `0` = "no record / not encoded" | client barrier wait | `ARCHITECTURE.md:124`: the wire carries no per-record seq field, so seq *is* the ordinal. `MGPReplySlot` exists (`MGPipeTypes.h:78-81`) and **no payload of the ten `kReplySlot` calls contains one** — which is exactly why the id must be derived rather than carried. P9 generalises this to "seq is the id's initial value", which extends the rule rather than overturning it. |
+| **reply slot header** | `{Uint64 Seq; Int32 Status; Uint32 Size;}` — 16 bytes, then the payload. `Status`: **0 = OK, 1 = DECLINED, 2 = ERROR**. | — | client | **`DECLINED` is a real answer, not a failure.** It is how `MapPersistent` says `nullptr` (R-6) and how the four `Bool` acceptance entry points say `false` (R-5). A client that treats DECLINED as an error re-creates ID-39's 66 lost uploads from the other side. |
+| **`kRecPad` and seq** | A wrap filler **does not advance seq**, on either side. | — | both | R-9. `RingConsumer::Pop` already skips fillers; the rule is stated because the *counter* is the caller's, not `Pop`'s. A side that counts pads drifts by one per wrap, for ever — and since seq is the reply-slot id, a drifted seq reads another call's answer instead of failing. Pinned by `RingTest.AWrapFillerDoesNotAdvanceTheRecordSequence`. |
+| **per-opcode flags** | `kMGPipeCallFlags[MGPWireOp::kOpCount]` in `generated/PipeWire.inc`, read only through `MGPipeCallFlagsFor(op)`. Index 0 (`kInvalid`) is `kNone`. | `kNone` = no flags | every package | R-13.4. Before this table existed nothing generated exported the flags, so six packages were each about to hard-code `PipeCalls.def`'s fourth column — which is how `GetCaps` and `CreateSamplerState` came to own an `MGPBlobRef` with no `kHasBlob` on their line. `gen_pipe.py` now also refuses a flag token that is not an `MGPipeCallFlags` enumerator, with two negative controls in `--self-test`. |
+| **`kHasBlob`'s meaning** | **Exactly "the payload owns an `MGPBlobRef` member"** — nothing weaker. | — | decoder | `PipeApply.h:78-79` already says so. Three calls carry bytes with **no** `MGPBlobRef`; they are table 1 rows 19–21 and are deliberately unflagged, because a decoder that trusts `kHasBlob` has to find a member to read. |
+
+---
+
+## §2 Table 1 — the byte carriers
+
+**23 rows, not 19.** BRIEF §3 lists 19 and `scout-premortem:§3` lists a different 19; the
+union is 23 and the four that only the premortem lists — `MapPersistent`, `ResourceReadback`,
+`ReadPixels`, `GetTextureImage` — are precisely the ones whose bytes travel **server → client**.
+Leaving them out of the byte-carrier table is how a phase discovers in week three that it never
+decided where readback pixels land. They are rows 20–23 and are marked with their owning phase.
+
+Columns: **flags** · **blob member** · **companion pointer today** · **which segment the bytes
+live in** · **who owns that memory** · **when the slot retires** · **who declares the length,
+who cross-checks it** · **reply name** (for `kReplySlot` rows).
+
+`apply` = retires when `DecodeAndApply` returns. `submit` = when the server has handed the bytes
+to the driver. `gpu` = `completedFrameSerial`.
+
+### Group A — `kHasBlob`, the payload owns an `MGPBlobRef`
+
+| # | call (op) | flags | blob member | companion today | segment | owner | retires | length declared / cross-checked |
+|---|---|---|---|---|---|---|---|---|
+| 1 | `CreateRenderState` (17) | `kHasBlob` | `Blob` (`MGPipeTypes.h:364`) | `const void* chunkBytes` (`PipeApply.h:740`), passed `CsoCache.h:157` | `SEG_STAGE` | client stages, server copies on apply | **apply** | declared real (`CsoCache.h:156`, `= kMGPipePipelineChunkBytes`); **nothing reads it today** — `MGPipeApplyCreateRenderState` (`PipeApply.cpp:1280`) never touches `Blob.Size`. Decoder must cross-check against `ChunkMask`. |
+| 2 | `CreateVertexElements` (20) | `kHasBlob` | `Blob` (`:419`) | `const void* blobBytes` (`PipeApply.h:932`), passed `VertexInputEmit.h:399` | `SEG_STAGE` | client stages, server copies | **apply** | declared real (`VertexInputEmit.h:398`); **cross-checked, and this is the model for every other row**: `PipeApply.cpp:1990-1999` recomputes `AttributeCount*sizeof(MGPVertexAttribWire) + BindingPointCount*sizeof(MGPVertexBindingPointWire)` and refuses a disagreement; both counts bounded by `kMGPipeMaxVertexAttribs`. |
+| 3 | `CreateShaderState` (27) | `kHasBlob` | **seven**: `Spirv[6]` (`:507`) + `Reflection` (`:508`) | **two typed frontend pointers** — `const LinkArtifacts*` + `const SpirvArtifacts*` (`PipeApply.h:1039-1041`), passed `ProgramEmit.h:257` | `SEG_STAGE`, seven independent runs | client stages, server copies | **apply** | all seven declare `Size = 0` today and `Reflection.Offset` is literally `(Uint64)&link` (`ProgramEmit.h:254`). **The serializer already exists and no package may write a second one**: `EncodeProgramArtifacts`/`DecodeProgramArtifacts` (`ProgramArtifactsCodec.{h:53,60,cpp:252,264}`), its own suite, and the verify build already round-trips **every real program it links** (`PinProgramArchiveRoundTrip`, `PipeApply.cpp:1056-1087`, called `:2638`). |
+| 4 | `SetDynamicState` (30) | `kHasBlob` | `Blob` (`:389`) | `const void* chunkBytes` (`PipeApply.h:748`), passed `PipeFill.cpp:2260` | `SEG_STAGE` | client stages, server copies | **apply** | declared real (`PipeFill.cpp:2259`); **nothing reads it** (`PipeApply.cpp:1363-1370` scatters by `ChunkMask`). Same fix as row 1. |
+| 5 | `SetGlobalConstants` (40) | `kHasBlob` | `Blob` (`:848`) | `const void* bytes` = `MapUBO()`'s image (`PipeApply.h:1052`), passed `ProgramEmit.h:195` | `SEG_STAGE` | client stages, server copies | **apply** | declares **0** (`ProgramEmit.h:194`); cross-check exists at `PipeApply.cpp:2784` against `Desc.GlobalUboSize` but is **inert while Size is 0**. Under rule A it becomes live. Per program per frame, unbounded length — the row most worth watching against R-10's max-record counter. |
+| 6 | `SetResidualValueState` (46) | `kHasBlob` | `Blob` (`:932`) | **none, and no record either**: the entry point is `MGPipeApplySetResidualValueState(const ResidualValueBlock&)` (`PipeApply.h:760`), passed `PipeFill.cpp:2184`. **`MGPResidualValueState` is never instantiated on the live path.** | `SEG_STAGE` | client | **apply** | nothing declares it. The encoder must invent **both** the record fill and the blob fill. `sizeof(ResidualValueBlock) == MGL_RESIDUAL_BLOCK_SIZE == 8` is statically asserted (`MGPipeTypes.h:924-927`) and only ever ratchets **down**. **This is the hardest row in the table** and neither scout flagged it; see §6. |
+| 7 | `ResourceSubData` (48) | `kHasBlob\|kVarTail` | `Blob` (`:1009`) | `const void* bytes` + `const MGPSubRegion* regions` (`PipeApply.h:897-899`); buffer half `PipeFill.cpp:705`, texture half `TextureEmit.h:1278-1280` | `SEG_STAGE` | client stages, **server must copy** (rule C names this call) | **apply** | **the two halves disagree today**: buffer declares real (`ResourceTracker.h:216`), cross-checked at `PipeApply.cpp:702`; texture declares **0** (`TextureEmit.h:1265-1267`) on the grounds that the byte count is *"the server's to compute once it has picked box-or-rects"* — which cannot be a bounds check. **Under rule A the texture half must declare too.** Tail: `MGPSubRegion[RegionCount]` (`:1007`). |
+| 8 | `BufferSubDataResident` (49) | `kHasBlob\|kOptional` | `Blob` (`:1009`, same payload) | `const void* bytes` = application staging, *"valid for the duration of the call only"* (`PipeApply.h:90`, `:901`); one caller, `PipeFill.cpp:727` | `SEG_STAGE` | client stages, server copies | **apply** | declared real via `MGPipeBuildSubDataRecord`, cross-checked at `PipeApply.cpp:702`. `kOptional` is a **capability** question under split, not a null-pointer question: the client must gate on `kCapResidentSubData` through the caps mirror, never on a table slot (R-8). |
+
+### Group B — `kVarTail`, a tail and no blob member
+
+Every row here declares its tail by a **count**, and `MGP_WIRE_CHECK_BOUNDS` **cannot see the
+tail at all** — it only proves `size >= sizeof(MGPWireRec_X)`, so a record declaring
+`Count = 4000` while carrying 8 bytes passes today. The decoder must recompute the total from
+the declared count(s) and require it to **equal** `MGPWireRecHeader::Size`.
+
+| # | call (op) | flags | tail element × count | companion today | segment | owner | retires | length |
+|---|---|---|---|---|---|---|---|---|
+| 9 | `SetVertexBuffers` (32) | `kVarTail` | `MGPVertexBuffer` × `Count` (`:730`) | `const MGPVertexBuffer*` (`PipeApply.h:941`), `VertexInputEmit.h:245` | `SEG_STAGE` (tail follows the payload in `SEG_CMD` only if it fits the record bound) | emitter-owned `Vector`, **reused next emission** | **apply** | `Count`; no tail cross-check today |
+| 10 | `SetSamplerViews` (35) | `kVarTail` | `MGPBoundView` × `Count` (`:778`) | `const MGPBoundView*` (`PipeApply.h:1028`), `SamplerEmit.h:786` | as above | as above | **apply** | `Count`; `Start+Count` past the unit bound is already `Fatal` (`PipeApply.h:1024-1026`) — a *slot* bound, not a byte-length check |
+| 11 | `BindSamplerStates` (36) | `kVarTail` | `MGPipeHandle` × `Count` (`:785`) | `const MGPipeHandle*` (`PipeApply.h:1029`), `SamplerEmit.h:860` | as above | as above | **apply** | as above |
+| 12 | `SetShaderImages` (37) | `kVarTail` | `MGPImageView` × `Count` (`:802`) | `const MGPImageView*` (`PipeApply.h:1030`), `ImageEmit.h:129` | as above | as above | **apply** | as above |
+| 13 | `SetShaderBuffers` (38) | `kVarTail\|kHostSpan` | **two tails**: `MGPBufferRange` × `Count` (`:826`), then `MGHostSpan` × `HostSpanCount` (`:828`) | **none — no applier entry point exists.** P5 writes the first producer *and* the first consumer. | `SEG_STAGE` | — | **apply** | `HostSpanCount` is 0 **or** `Count`, never anything else (`MGPipeTypes.h:820-823`), so the two arrays stay index-aligned. `kCapNeedsHostUboBytes` is 0 for all of P5, so the second tail is **always absent** in this phase. |
+| 14 | `SetStreamOutputTargets` (39) | `kVarTail` | **two tails**: `MGPBufferRange` × `Count`, then `Uint32` × `Count` (`:836-838`) | **none — no applier entry point exists.** | `SEG_STAGE` | — | **apply** | one `Count` sizes both tails; off the reduced path in P5 |
+| 15 | `SetVertexAttribDefaults` (41) | `kVarTail` | `MGPAttribValue` × `Count` (`:864`) | `const MGPAttribValue*` (`PipeApply.h:756`), `PipeFill.cpp:2115` | as above | as above | **apply** | **two declarants that must agree**: `Count` and `popcount(Mask)` (`:863`, contract at `PipeApply.h:754-755`). A disagreement is a wire fault nothing checks today; the decoder must. |
+| 16 | `DrawVbo` (59) | `kHostSpan\|kVarTail` | `MGPDrawRange` × `NumDraws` (`:1239`), then a **conditional** `MGHostSpan` when `Flags & kDrawHasUserIndices` (`:1212`, `:1231`) | **none — no applier entry point exists.** | `SEG_STAGE` | — | **apply** | `NumDraws`; the span carries its own `Size`. **The only `kHostSpan` on the hot path, and P5 must produce none of them** — `TriangleScenario` uses a VBO-backed draw precisely so this tail never appears. `MGPipeTypes.h:1221-1224` defers the fixed-head-versus-tail question to this phase: **P5 keeps it in the tail, unchanged**; there are no per-draw byte histograms yet to justify moving it, and moving it would be a wire-format change with no measurement behind it. |
+
+### Group C — carries content with **no** `MGPBlobRef` and **no** `kHasBlob`
+
+These three are the reason `kHasBlob` had to be given an exact meaning (table 0).
+
+| # | call (op) | flags | ruling | evidence |
+|---|---|---|---|---|
+| 17 | `CreateSamplerState` (23) | **now `kHasBlob`** (R-13.1) | `MGPSamplerDesc` **does** own an `MGPBlobRef Parameters` (`:429`) and the flag was simply missing. The blob is `memcpy(sizeof(SamplerParameters))` — a POD, and **`borderColorForm` must survive byte for byte** (`MGPipeTypes.h:425-428`), because all three colour representations are always numerically populated and it is the only thing that says which one the backend must use. | companion today is a **typed frontend pointer**, `const SamplerParameters*` (`PipeApply.h:1000`), passed `SamplerEmit.h:458`. Declares `Size = 0` (`SamplerEmit.h:433-435`); cross-check at `PipeApply.cpp:2353` is inert until rule A arms it. **Padding trap:** `SamplerEmit.h:437-445` — assignment leaves three trailing padding bytes stale, and the bytes staged must be the bytes a later `memcmp` compares. |
+| 18 | `GetCaps` (1) | **now `kReplySlot\|kHasBlob`** (R-13.1) | `MGPCaps` owns **two** `MGPBlobRef`s, `FormatCapabilities` and `RendererInfo` (`:137-138`), and carried no `kHasBlob` at all. | `PipeCalls.def:80` before the fix. Serializers are P5's new work (`MG_Remote/CapsCodec.h`); the header itself defers them to this phase (`MGPipeTypes.h:134-136`). |
+| 19 | `ResourceRespecify` (3) | stays `kNeedsAck`, **no `kHasBlob`** (R-13.3) | **`initialBytes` is always `nullptr` under split. Initial content arrives as `ResourceSubData` records immediately after this one.** `MGPResourceDesc` owns no `MGPBlobRef` and gains none. | The alternative was costed and rejected: `MGPBlobRef` is 24 bytes, `MGPResourceDesc`'s two pads are `Uint16 Pad0` (`:303`) + `Uint32 Pad1` (`:315`) = **6 bytes**, so a blob member takes the struct 88 → 112 and moves `MGP_ASSERT_POD(MGPResourceDesc, 88)` (`:320`). The chosen route reuses a path that is already chunked (`MGPipeForEachSubDataRecordRange`, `PipeFill.cpp:694-713`) and already acceptance-gated; it costs one extra record. `HasDefinedContent` (`:301`) is the field the encoder branches on, and it already exists. **The texture path already does exactly this** — `TextureEmit.h:1137` passes `nullptr` and relies on a following upload — so this generalises today's texture behaviour to buffers rather than inventing anything. |
+| 19b | `ResourceRespecify`'s **second** uncarried companion | — | **`const MGPRespecifiedLevel* level` (`PipeApply.h:792-795`, 4 bytes: `Uint16 UploadTarget; Uint16 Level;`) has no wire carrier either, and it is not bytes — R-13.3 does not cover it.** Ruling: it rides in `MGPResourceDesc`'s existing pads — `Pad1` (4 B, `:315`) becomes `{Uint16 RespecifiedUploadTarget; Uint16 RespecifiedLevel;}` and one byte of `Pad0` (`:303`) becomes `Uint8 HasRespecifiedLevel`. **Zero size change, `MGP_ASSERT_POD(..., 88)` does not move**, and `PipeFields.def`'s `MGP_FIELDS_MGPResourceDesc` gains the two named members (pads are excluded from field lists, so this is required, not optional). | Null means "this respecify redefines the **whole** resource" and drops every pending upload; non-null names the single `(uploadTarget, level)` and drops **only** that key. Clearing the whole set for a per-level `glTexImage2D` loses exactly the texels the server-side set exists to protect (`PipeApply.h:805-820`). Without a carrier, every OpenRA per-level respecify would silently take the whole-resource arm. **LANDED** (integrator ruling A made `MGPipeTypes.h` c0's file): `Uint8 HasRespecifiedLevel` in Pad0's high byte, `Uint16 RespecifiedUploadTarget; Uint16 RespecifiedLevel;` in Pad1, `MGP_ASSERT_POD(MGPResourceDesc, 88)` unmoved, plus an `offsetof` assertion that the pair stays adjacent and in `MGPRespecifiedLevel`'s order. **Read it only through `MGPipeRespecifyIsWholeResource` / `MGPipeRespecifiedUploadTargetOf` / `MGPipeRespecifiedLevelOf`, and write it only through `MGPipeSetRespecifiedLevel` / `MGPipeClearRespecifiedLevel`**: three fields are one value, and an open-coded reader that forgets the presence byte reads level 0 of upload target 0 as a real scope. **The carrier has no producer** — P5 builds only whole-resource descriptors, and a verify build pins that (`PinWholeResourceRespecifyScope`, `PipeApply.cpp`, the `PinNoLiveHostWrites` shape) so the phase that wires it cannot arrive unannounced. |
+| 20 | `ResourceFlushRange` (51) | stays `kNone` (R-13.2) | **It carries no bytes at all under split.** It is a `{range, AccessFlags}` control record; the bytes of `[Offset, Offset+Size)` arrive **ahead of it** as `ResourceSubData` records covering exactly that range. | R-13.2 offered "add a blobref" or "write the convention down". Neither, and for a reason: the ladder this record drives rewrites its range *"from the authoritative shadow"* (`Managers.cpp:1047-1076`), and under split the authoritative shadow is **server-owned** by rule C — so `resource_subdata` is already the only way bytes reach it, and a blobref here would be a second, forgeable way to say the same thing. `AccessFlags` must still cross **verbatim**, not normalised (`PipeApply.h:902-903`). **Overturn condition:** if the tier-1 `INVALIDATE_RANGE` arm turns out to need the bytes and the range in the *same* record — i.e. an intervening record could stale the subdata — this needs its own blobref. It cannot happen while the verb barrier holds, because nothing interleaves; **revisit when the barrier retires for the buffer family.** |
+
+### Group D — the four server → client rows the brief's list omitted
+
+| # | call (op) | flags | ruling | reply name |
+|---|---|---|---|---|
+| 21 | `MapPersistent` (5) | `kReplySlot\|kOptional` | **Returns `nullptr` under split, always** (R-6/R-2.4). Its `const void* seedBytes` companion (`PipeApply.h:917`) therefore never crosses in P5 and needs no carrier. The three frontend sites already tolerate a decline (`BufferObject.cpp:238`, `:603-606`, `:657-660`). Answer travels as `Status = DECLINED` with a zero-length payload. | `map_persistent.decline` |
+| 22 | `ResourceReadback` (52) | `kReplySlot` | Bytes go **server → client** in `SEG_EVENT` via `OnBufferWriteback` (#3), not in the reply slot: the destination is the client's shadow and the size is the resource's, not a fixed slot's. The reply slot carries only completion. **The ordering rule is load-bearing:** the writeback is applied **before** the mutation epoch bumps, never after (`ARCHITECTURE.md:292-294`, `Managers.cpp:2120-2136`). | `resource_readback.done` |
+| 23 | `ReadPixels` (58) / `GetTextureImage` (55) | `kReplySlot` | **`ReadPixels` blocks in P5** and its pixels come back in the reply slot, which is why `ReplyPool::SlotBytes()` is sized from the scenario's largest read rather than guessed. `MGPReadbackInfo` has `DstOffset`/`DstSize` but **no `Seg`** (`MGPipeTypes.h:1197-1206`): ruling — the destination is **always `SEG_REPLY`** in P5, so no `Seg` field is added; the PBO destination (fire-and-forget plus a client-side `MarkGpuWritten`) is b1's and also needs none, because a PBO destination is a resource handle rather than a segment. `GetTextureImage` is **not on P5's reduced path** and its slot stays `Fatal{UnmigratedVerb}`. | `read_pixels.pixels` |
+
+---
+
+## §3 Table 2 — `PipeInputs` field ownership
+
+**This section is the SPEC and the four class definitions. The authoritative instance is
+generated**: package p1 writes the generator that emits `generated/PipeFieldOwnership.inc` plus
+a `--check`, in the shape of `gen_pipe_dirty_surface.py`. **A field in none of the four classes
+is a build failure** (R-7.1) — that is the whole mechanism, and a hand-maintained table would
+be wrong within a week.
+
+The domain is **63 fields** (`kMGPipeInputFieldCount`, asserted `generated/PipeFilled.inc:96`)
+**plus the 7 sticky forwards**, which are among those 63 but are exempted from the poison and
+so need their own row. 70 rows, each in exactly one class.
+
+### The four classes
+
+**RECORD-SUPPLIED** — a pushed record supplies the **whole** field, so the server never needs
+the client for it.
+Membership is `kMGPipeFieldEmittedBy` (`generated/PipeFilled.inc:336-402`,
+`kMGPipeEmittedFieldCount = 40`) **minus** the nine for which
+`EmittedCallSuppliesTheWholeField` returns false (`MG_Impl/Pipe/PipeFill.cpp:1924-1939`;
+reasons `:1875-1923`). **31 fields today.**
+The nine excluded, with the generator's own reason: `GetPixelStoreParameters` ("only the PACK
+half has a carrier"); `GetCurrentVertexAttribute` ("the applier cannot reproduce GLContext's
+cross-view conversion"); `GetMaxTouchedTextureUnit` ("the set is hash-suppressed while the
+high-water mark still moves"); and six sharing one reason — "the storage is a frontend heap
+reference and the record carries an 8-byte `{slot, gen}`" — `GetBoundVertexArray`,
+`GetFramebufferBindingSlot`, `GetImageTextureBinding`, `GetTextureUnitObject`,
+`GetProgramForDraw`, `GetProgramForDispatch`.
+
+**APPLIER-DERIVED** — the applier writes it from the records it already applies; no client
+participation at all. Today: the render-state mirrors, `m_pixelStore[0]` (the **pack** half),
+capability bits, the current vertex attribute, and the patch fields — written at
+`PipeApply.cpp:177-184`, `:1338-1437`, plus everything `MGPipeDeriveRenderStateFields`
+(`PipeApply.h:1084`, `PipeApply.cpp:2157`) derives.
+
+**BARRIER-PULLED** — **P5's debt, and every row names the phase that retires it.** The server
+answers by reading a value the client's residual fill put into the single shared `gPipeInputs`
+while the verb barrier holds both threads apart. It is correct only because of that barrier,
+which is why the barrier is load-bearing rather than cautious.
+Each read increments `PipeStats::CallClass::ResidualPulls` (short name `rsp`, inside the
+`#if MOBILEGL_PIPE_PUSH` block so G1 holds), published per frame. **`rsp`'s value at the end of
+P5 is the size of the P6/P7/P8 debt** and goes into MEASUREMENTS.
+`MOBILEGL_IPC_STRICT_ERRORS=1` promotes every read in this class to `Fatal`, and a named test
+asserts the abort actually happens — an instrumentation that cannot go red is decoration.
+
+**FATAL** — no carrier, and the reduced path never reads it, so a read is a real defect.
+`Fatal{UnmigratedPipeInput, "<Field>@<verb>"}` (`generated/PipeFilled.inc:407-413`), live at
+every log level on purpose (`PipeInputs.h:29-31`: *"this is not `MOBILEGL_ASSERT`, which is
+inert in INFO builds"*).
+
+### The known BARRIER-PULLED rows — the 21 the reduced path actually reads
+
+Union of `kClear` (7 of its 18 own fields), `kDraw` (19 of 47) and `kReadback` (12 of 17).
+OpenRA adds no field to this set — it widens the **site** set, not the field set, and is the
+first thing to reach the read-attachment sites (`Managers.cpp:8603`, `:8966`) and the
+`maxTouchedUnit >= 0` texture-unit walks.
+
+| field | class | retires in | note |
+|---|---|---|---|
+| `GetBoundVertexArray` | O | **P8** | `DirectGLES.cpp:4486`, `PrepareForDraw`, **unconditional on every draw**. `PipeFill.cpp:1902-1905` says the pull retires at P8, not here. |
+| `GetProgramForDraw` | O | **P8** (Espryt), P7 (Magma) | `DirectGLES.cpp:4497`, same site, also unconditional. |
+| `GetBufferBindingSlot` | O | P8 (indirect half), P9 (readback), P13 (transfer) | 18 Espryt sites; the 7 of 15 `BufferTarget`s no call covers (`Coverage.def:37-70`). |
+| `GetBufferBindingPoint` | O | P3b/P4b + P7 | |
+| `GetTouchedBufferBindingPointCount` | V | P3b/P4b | |
+| `GetFramebufferBindingSlot` | O | P3b/P4b (Espryt), **P7** (Magma) | 8 Espryt sites through `GetFramebufferBindingSlotChecked`; `SyncCurrentFBO` (`:2995`) is self-declared monolith glue (`DirectGLES.cpp:2961-2965`) while `BindCurrentFBO` (`:4303-4353`) is already split-clean. |
+| `GetTextureUnitObject` | O | P3b/P4b, P7 | 13 Espryt + 8 Magma sites. |
+| `GetImageTextureBinding` | O | P3b/P4b, P7 | |
+| `GetActiveTextureUnit` | V | P3b/P4b | server answers from its own state (`Coverage.def:215-219`). |
+| `GetMaxTouchedTextureUnit` | V | P3b/P4b | hash-suppressed set, high-water mark still moves. |
+| `GetTextureContextId` | V | P3b/P4b | **not a value to migrate**: the server answers from its own `Serial`. `Coverage.def:220-224` is explicit that no call carries these three and none should. |
+| `GetTextureBindGeneration` | V | P3b/P4b | as above |
+| `GetSamplingResolutionGeneration` | V | P3b/P4b | as above |
+| `GetCurrentVertexAttribute` | V | P3b/P4b | the applier cannot reproduce GLContext's cross-view conversion. |
+| `GetPixelStoreParameters` | V | **split in P5 — see below** | |
+| `IsTransformFeedbackActive`, `IsTransformFeedbackPaused`, `GetTransformFeedbackProgram`, `GetTransformFeedbackGeneration`, `GetBoundTransformFeedbackLifetimeId`, `GetTransformFeedbackCapturedVertices` | V/O | P3b/P4b (Espryt XFB scatter), P7 (Magma) | read on `kDraw`; XFB itself is off the reduced path but these are read on the draw walk regardless. |
+
+**`GetPixelStoreParameters` is split into pack and unpack in this phase** (R-7's one small
+migration, and it is c0's ruling to keep rather than soften). The field is `m_pixelStore[2]` and
+only `[0]` (pack) has a carrier — which the applier does write (`PipeApply.cpp:1373`) — so the
+whole field reads as unmigrated while the half a readback needs is fine. Splitting it is what
+stops the readback path from taking a whole-field `Fatal` for a half it never touches. The five
+Espryt read sites whose `isUnpack` argument decides which half they want are
+`DirectGLES.cpp:7924`, `:9399`, `:10893`, `:11272` and `Utils.cpp:2302`; **the scout named them
+and did not open them**, so p1 reads the argument at each before it writes the two rows.
+
+### The FATAL rows
+
+Three non-sticky fields, each off the reduced path for a different, checkable reason:
+
+| field | why it is FATAL rather than pulled |
+|---|---|
+| `GetBoundTransformFeedbackName` | **dead** — read by no backend since D21 (`PipeInputs.h:232-234`). |
+| `GetTransformFeedbackPausedPrimitiveCounter` | reachable only from class `kQuery`, which the reduced path never enters. |
+| `GetProgramForDispatch` | reachable only from `kDispatch`; there is no compute on the reduced path. Sites: `DirectGLES.cpp:5779`, `VulkanRenderer.cpp:7327`, `:7379`. |
+
+Plus **`MGPipeUnmigratedEmulation`'s five call sites**, which in a split build stop being
+`(void)name;` and become `Fatal`: `Managers.cpp:5334` ("texture-remint-pull"),
+`DirectGLES.cpp:8051` ("generate-mipmap-storage"), `:8702` ("generate-mipmap-cpu-fallback"),
+`:8997` ("copy-image-shadow-mirror"), `:10623` ("get-tex-image-shadow"). **One function grows
+teeth and five sites get them** — `PipeApply.cpp:2820`, today a no-op, which
+`PipeApply.h:1055-1066` and `PipeApply.cpp:2812-2817` both already say is waiting for this
+phase. None of the five is on the reduced path. (ROADMAP's P4a row says six sites; there are
+**five calls and one comment** — `Managers.cpp:5287` is the comment.)
+
+### The seven sticky forwards
+
+`GetBufferBindingPointCount`, `GetProgramObject`, `GetTextureObject`,
+`HasOpenTransformFeedbackSpan`, `ValidateProgramName`, `InvalidateCompileEnv`, `RecordError`
+(`PipeInputs.h:569-577`; identity asserted `:135-137`; argued `Coverage.def:138-150`).
+
+P5's assignment:
+
+- the first five → **BARRIER-PULLED** (counted in `rsp`, `Fatal` under strict);
+- `InvalidateCompileEnv` → **`OnCapsInvalidated`**, i.e. the re-arriving caps snapshot (R-12);
+- `RecordError` → **BARRIER-PULLED**, counted in `rsp`; its *ordering* is P9's (`OnGlError`).
+
+**And their exemption is cancelled in a split build.** Today F-class accessors carry no
+`MGP_INPUT_CHECK` at all (`PipeInputs.h:563-568`) and `MGPipeInputFieldIsFresh`
+(`generated/PipeFilled.inc:418-426`) answers "fresh" for a sticky field regardless of
+generation. That is exactly backwards for this phase: these seven are the ones that hand a
+**frontend object or a frontend write** straight to the backend, so the exit gate "an
+unmigrated field read is Fatal" is structurally blind on the seven most dangerous fields.
+Under `MOBILEGL_BUILD_DISAGGREGATED` the exemption is lifted so they enter `rsp`, and under
+`MOBILEGL_IPC_STRICT_ERRORS=1` they become `Fatal` like any other BARRIER-PULLED row.
+
+### The prerequisite nobody else owns: someone must stamp
+
+`MGPipeApplyAccess` **deliberately does not stamp** the poison generations
+(`PipeInputs.h:612-618`): *"a stamp says the filler published this for THIS verb, which is the
+walk's statement, not the applier's"*. Under split the filler is in the other role, so nothing
+stamps, every `FilledGen[]` stays 0, `MGPipeInputFieldIsFresh` returns false for **everything**,
+and a purely-server-side read aborts on the **first** field inside `SyncRenderState` —
+`Fatal{UnmigratedPipeInput, "GetRenderStateParameters@<none>"}` — long before any interesting
+case. **The server stamps at the verb boundary**: p1 defines what is stamped and for which
+verb, v1 places the call (`Server/PipeApplier::StampVerbBoundary`). Neither half works alone,
+and this is not in the ROADMAP row.
+
+### Two sets with no field ids
+
+**The conservative client GPU-write set.** One row per backend `MarkGpuWritten` site, mapped to
+the client predicate that must fire, one unit case each:
+
+| backend site | what it marks | when |
+|---|---|---|
+| `DirectGLES.cpp:570` | every SSBO binding point | draw/dispatch about to go out |
+| `DirectGLES.cpp:618` | every bound atomic counter | every conformance case reads the increment back |
+| `DirectGLES.cpp:2603` | buffer textures on image units, **only when `Access != GL_READ_ONLY`** | from draw preparation, deliberately not from `glBindImageTexture` |
+| `UniformManager.cpp:1075` | storage texel buffer, `Access != GL_READ_ONLY` | after `EnsureGpuResidentStorage()` |
+| `UniformManager.cpp:1231` | SSBO block, unconditional | after `EnsureGpuResidentStorage()` |
+| `VulkanRenderer.cpp:11618` | the XFB capture targets | "the capture is a GPU write like any shader's" |
+
+Plus **two new producers P5 adds**, both client-side with no server participation
+(`ARCHITECTURE.md:508`): `glReadPixels` into a pack PBO becomes fire-and-forget plus a client
+`MarkGpuWritten` (strictly better than monolith's unconditional stall), and
+`glEndTransformFeedback` drops its unbounded fence wait and marks the capture targets instead.
+
+`SyncGpuWrites` gains a **third state** it cannot express today — *emitted, answer not back* —
+and under split it must **block until `OnBufferWriteback` lands** rather than clear the flag
+optimistically (`BufferObject.cpp:372-374` clears unconditionally; `ARCHITECTURE.md:509` lists
+this among the unavoidable blocking points, because monolith already `glFinish()`es here).
+**No narrowing in P5**: `ResourceTracker.h:587-592`'s `rangeCount == 1` assertion **stays**.
+
+**The persistent-map reachable set: the census is 21 sites, not 20.** `MEASUREMENTS.md:111`
+records 20 and `Managers.cpp:5047-5048` speaks of "the eleven Espryt" sites; the actual count
+is **9 Espryt + 12 Magma = 21**, and Espryt's own count is 12 (9 + 3 `SyncGpuWrites`), so both
+published numbers are exactly one low and the missing one is an Espryt line. **Ruling: 21 is
+the number, and `DirectGLES.cpp:361` (`ResolveIndirectCommandBytes`) is in the set.** It is a
+shared helper rather than a draw-path site, which is the most likely reason it was excluded,
+but a helper that reaches a persistently-mapped range is exactly as able to read stale bytes as
+a draw site is; excluding it would be a shutter that cannot see its own subject. The
+per-site attribution table `ARCHITECTURE.md:290` refers to as "§5.7" **does not exist in the
+tree** — b1 should not go looking for it. The nine Espryt sites: `DirectGLES.cpp:361`, `:6185`,
+`:6439`, `:6440`, `:6541`, `:6542`, `Managers.cpp:2817`, `:2994`, `MultiDraw.cpp:511`. The
+twelve Magma: `DirectVulkan.cpp:281`, `:472`, `:796`, `UniformManager.cpp:2024`,
+`VulkanRenderer.cpp:3542`, `:3621`, `:4013`, `:7428`, `:12423`, `:12424`,
+`VkBufferManager.cpp:628`, `:679`. **Correcting `MEASUREMENTS.md:111` from 20 to 21 is b1's
+line to write**, in the same commit that lands the tracker.
+
+`m_livePersistentMaps` is defined by `SyncPersistentMappedRange`'s own early-out chain read as
+a membership test (`BufferObject.cpp:346-349`): persistent, write, **not** flush-explicit,
+**not** GPU-resident.
+
+---
+
+## §4 Table 3 — role and thread ownership of every process global
+
+`ARCHITECTURE.md:578-581` claims MGPipe brings the globals a role split must duplicate down
+from four to two. **That census is at least seven short.** Every row below also answers what
+make-current and teardown do to it — the column `ARCHITECTURE.md` does not have.
+
+| global | where | who writes | P5 ruling | make-current / teardown |
+|---|---|---|---|---|
+| `gPipeInputs` (~20 KB) | `PipeInputs.h:706` | client residual fill (`PipeFill.cpp:530`, `:2131`, `:2604`) + applier (`PipeApply.cpp:1336`, `:1364`, `:1373`, `:1377`, `:1436`, `:1512`) | **One instance is legal, but only under the verb barrier.** The barrier makes at most one of {GL thread, apply thread} runnable at a time, so there is exactly one writer at any instant. **No second writer may be introduced before the barrier retires.** The invariant is a runtime assertion in debug/verify builds, not only a sentence here: the apply thread raises a flag on entering the applier and the client checks it when it touches `gPipeInputs` outside a barrier (`ClientSession::InBarrierWait` / `ApplyThreadIsInsideApplier`). | make-current: unchanged. teardown: nothing — it is POD in the image. |
+| `g_applier` | `PipeApply.cpp:396` | applier | **Server-exclusive.** Its own header already says "under split there is one per served context" (`PipeApply.h:684`). | It is `*new MGPipeApplierState{}` and never destroyed, deliberately (`PipeApply.cpp:392-395`): `resource_destroy` is raised from `~BufferObject`, which runs from exit handlers after this TU's globals are gone. |
+| `g_resourceOps` | `PipeApply.cpp:402` | the backend, at register time | **Server-exclusive, and the client must NEVER read it** (R-8). Under `inproc` a client reading it is right *by accident*; under spawn it is null and the four P4a families plus P3a's buffers emit **nothing at all**, silently. The client asks `CapsMirror::ServerConsumes` instead. | registered around `DirectGLES.cpp:11933`, nulled from `OnBackendContextDestroyed` (`Managers.cpp:2584`) — so it moves on every context loss, which is another reason the client cannot key on it. |
+| `gMGPipeSegmentResolver` | `MGPipeHostSpan.h:47` — a **plain non-atomic inline variable** | `MG_Remote` installs | **One process-wide slot, so it cannot be per-role.** Ruling: **the server role installs it and the client never resolves a span at all** — the client only ever *writes* `Ptr = nullptr`. `SegmentTable::InstallProcessResolver()` asserts if one is already installed, so two roles racing on it is loud rather than silent. Install **before** the apply thread starts. | teardown: uninstall after the join, never before — a record still in flight can still resolve. |
+| the ten `MG_Impl/Pipe` `*Instance()` singletons | `fable-seam-audit.md:120-135` | client | **Client-exclusive.** One correction carried forward: the texture **drain list `m_drain` is process-wide**, not per-context as D-D4 claims; the audit already booked "one drain per client context" as a P5 item. | `FreshlyPrimed` (`PipeFill.cpp:2414-2440`) resets them on make-current; leak at exit (ID-8). |
+| `ScopedDefaultUnpackState::s_synced` + **six** value shadows | `Managers.cpp:5490-5496` | backend | **Server-exclusive — the sixth global the four→two census missed.** Latent rather than live in P5 only because the client role never touches GL on the reduced path. (`Managers.cpp:5491-5496` is six `GLint`s, not five: `s_skipImages` at `:5496` is the one usually dropped.) | **Never reset on context death** — `OnBackendContextDestroyed` resets the rings and the binding caches and not this. Benign while a lost context returns the driver to GL defaults; not benign the day a server re-attaches to a context something else moved. Register it now. |
+| `pActiveBackendObject` | `GlobalObjects.cpp:23` | `MG_Backend::Init()` | **Client installs `BackendObject_Remote`; the server's `BackendObject_DirectGLES` is held privately by `ServerLoop`.** No thread-keyed shim, and therefore `MOBILEGL_BUILD_DISAGGREGATED_INPROC` needs none — but the cost is **seven** backend-internal reads across **six** functions, not the one the scout reported: `BackendObject_DirectGLES.cpp:815`, `:819` (`ClampSamplesToBackendSupport`) and `Utils.cpp:74`, `:82`, `:126`, `:220`, `:260`. All seven are format-capability lookups, so "pass the format cache down" still works. **`DirectGLES.cpp:12446` is NOT `ClampSamplesToBackendSupport`** — it is `Present()`'s fence poll, and `DirectGLES.cpp` contains no `pActiveBackendObject` reference at all. | `GetFormatCapabilities()` is **non-virtual** (`BackendObject.h:594`), so the remote object must **fill** `m_formatCapabilities` rather than override the accessor. Teardown: `pActiveBackendObject.reset()` (`MobileGL/Init.cpp:68`) runs `~BackendObject_DirectGLES` → `DestroyEGLContext()`, so under split it must be a **blocking** request onto the apply thread. |
+| `gBackendFunctionsTable` | `GlobalObjects.cpp:24`, assigned `Init.cpp:44` | `MG_Backend::Init()` | **Client = the emit table (R-4); the server holds its real table directly and never goes through this global.** | cleared at `MobileGL/Init.cpp:91`. |
+
+**Teardown order**, `ARCHITECTURE.md:537` plus the sentence it omits:
+
+1. client publishes and waits for the server to drain and acknowledge;
+2. **`Doorbell::Kill()`** — *the only thing that can wake an apply thread parked on
+   `kWaitForever`* (`Doorbell.h:211-221`; the shape is already pinned by
+   `InProcessTransportTest.cpp:344`);
+3. **join**, bounded (that test uses 5 s) so a regression is a red test and not a hung CI job;
+4. only then may the client free anything an emitter owns — a tail still referenced by an
+   unapplied record is a use-after-free the join is what prevents;
+5. then the existing order (`MobileGL/Init.cpp:38-98`).
+
+**ID-8 applies once per role-local singleton, not once overall**: every new
+`MG_Remote/Client/*` and `MG_Remote/Server/*` singleton leaks at exit. The proof recipe is
+inherited: both lanes run `GLIBC_TUNABLES=glibc.malloc.tcache_count=0`.
+
+**Known open item, flagged not resolved.** `ARCHITECTURE.md:537`'s required order puts the
+client's sync/query handle release **after** the transport closes, while today
+`DestroyAllSyncObjects` / `DestroyAllQueryObjects` (`MobileGL/Init.cpp:62`, `:67`) deliberately
+run **before** `pActiveBackendObject.reset()` (`:68`). The two are only reconcilable if a split
+sync handle is client-minted and needs no backend call — which is P10's, not P5's. **P5 keeps
+today's order** and v1 records which way it went.
+
+---
+
+## §5 The knobs
+
+Parsed in `ConfigLoader.cpp`, declared in `Config.h`. All of them live behind
+`#if MOBILEGL_BUILD_DISAGGREGATED` — including the parser — because `MG_ConfigLoader::Init()`
+is a pull-build symbol and G1 admits **no resize**, which is the same reason the
+`MOBILEGL_PIPE_VERIFY` knobs sit behind their own `#if`.
+
+| knob | default | notes |
+|---|---|---|
+| `MOBILEGL_TRANSPORT` | `monolith` | `monolith\|inproc\|spawn\|unix:<path>\|pipe:<name>`. The three P6 forms **parse and are then refused by name**, staying on monolith: a P6 lane that set `spawn`, fell back silently and went green on the wrong arm is the failure this wording avoids. |
+| `MOBILEGL_IPC_SERVER_PATH` | `""` | P6 consumes it; P5 parses it because t1's ctest `ENVIRONMENT` blocks and `add_trace_replay_test`'s SPLIT variant already carry it, and an unparsed variable is indistinguishable from a parsed-and-ignored one. |
+| `MOBILEGL_IPC_RING_MB` | 8 | SEG_CMD. **One record may be at most half of this** (`RingProducer::MaxRecordBytes`), so 8 MiB caps a record at 4 MiB. R-10 makes the codec publish a max-record-bytes counter rather than assume that is enough. |
+| `MOBILEGL_IPC_STAGE_MB` | 32 | SEG_STAGE. Every blob and every var-tail's bytes. |
+| `MOBILEGL_IPC_SPIN_US` | 50 | spin before parking, either direction. |
+| `MOBILEGL_IPC_PERSISTENT_BLOCK_KB` | 64 | **0 is the E3(a) negative control, not "unlimited"**: it turns the push off and `PersistentCoherentMapScenario` must go red. |
+| `MOBILEGL_IPC_ADOPT_TIER` | 2 | 2 = emulate, the only tier P5 implements. 0 and 1 parse and are `Fatal` at use, naming P11. |
+| `MOBILEGL_IPC_VERB_BARRIER` | 1 | 0 is R-1's negative control and is **expected** to be red. |
+| `MOBILEGL_IPC_STRICT_ERRORS` | 0 | promotes BARRIER-PULLED reads — and, in a split build, the seven sticky forwards — to `Fatal`. |
+| `MOBILEGL_IPC_AUDIT` | 0 | `0xDD` over retired staging bytes (rule C's mechanical control). |
+| `MOBILEGL_IPC_SERVER_AFFINITY` | `auto` | kept as the raw string; whoever starts the apply thread logs the **resolved mask**, because an affinity that silently did nothing looks exactly like one that worked. |
+
+**One consequence, stated so it is not rediscovered.** In a build *without*
+`MOBILEGL_BUILD_DISAGGREGATED`, `MOBILEGL_TRANSPORT=inproc` is accepted by the environment and
+**silently ignored** — the parser does not exist there, and putting a complaint in the
+unconditional part of `ConfigLoader` would move a pull-build symbol and break G1. That is
+precisely the shape of "the split lane ran monolith and went green", so the guard against it is
+a **build-level** check, not a runtime one: `nm --defined-only libMobileGL.so | grep -i
+MG_Remote` must be non-empty in `build-split`, and it is t1's CI job to assert that.
+
+CMake gained `MOBILEGL_BUILD_DISAGGREGATED_INPROC` (implies `DISAGGREGATED`) and, new here,
+**`MOBILEGL_BUILD_DISAGGREGATED` now implies `MOBILEGL_PIPE_PUSH`**: the split path decodes
+into the MGPipe applier and `MOBILEGL_PIPE_PUSH` is what compiles the applier, so
+`-DMOBILEGL_BUILD_DISAGGREGATED=ON` alone used to configure cleanly and then fail to link — a
+shape indistinguishable at the CMake level from a legitimate transport-only build.
+
+---
+
+## §6 Rulings this file makes that the brief did not, and where the brief is wrong
+
+Each entry says what would overturn it.
+
+1. **`CallMask` bits 32..47 are the consumer mask.** R-8 says the client's liveness gates read
+   the `CallMask` mirror, but `CallMask` as declared has only nine feature bits and no
+   per-family bit, so R-8 was not implementable as written. Overturned by: a decision to carry
+   a second mask field in `CapsSnapshot` instead — which costs a schema field and gains
+   nothing, since 16 bits is enough through P8.
+
+2. **`tableSlotMask` is deleted, not renamed** (R-8 allowed either). Decisive evidence:
+   `GLFunctionsTable` has **69** slots and `ulong` is 64 bits, so the field cannot address the
+   table its own comment names. Overturned by: widening the schema field *and* a reason to
+   keep an explicit slot probe after `ARCHITECTURE.md:114` retired the concept.
+
+3. **`ResourceFlushRange` carries no bytes at all** (R-13.2 offered "add a blobref" or "write
+   the convention down"; this is a third answer, and a stronger one). The ladder it drives
+   rewrites from the authoritative shadow, which under rule C is server-owned, so
+   `resource_subdata` is already the only path bytes take. Overturned by: evidence that the
+   tier-1 `INVALIDATE_RANGE` arm needs bytes and range in one record. Cannot arise while the
+   verb barrier holds; **revisit when the barrier retires for the buffer family.**
+
+4. **`ResourceRespecify` also has a SECOND uncarried companion, and the brief does not mention
+   it.** `const MGPRespecifiedLevel* level` (`PipeApply.h:792-795`) is the *scope* of the
+   redefinition and `MGPResourceDesc` cannot express it. Without a carrier every per-level
+   `glTexImage2D` in OpenRA silently takes the whole-resource arm and drops every pending
+   upload — the exact texel loss the server-side set exists to prevent. Ruling: two named
+   fields in the existing pads, zero size change. **c0 rules and specifies; the integrator
+   lands the `MGPipeTypes.h` + `PipeFields.def` edit before w1 encodes this record.**
+
+5. **Table 1 is 23 rows, not 19.** The brief's 19 and `scout-premortem:§3`'s 19 are different
+   lists; the four only the premortem carries are the server → client ones, and a phase that
+   omits them discovers in week three that it never decided where readback pixels land.
+
+6. **`SetResidualValueState` is a fourth typed companion, and neither scout nor the brief names
+   it.** `MGPipeApplySetResidualValueState` takes `const ResidualValueBlock&` — not a payload,
+   not a `const void*` — and `MGPResidualValueState` is **never instantiated on the live path**.
+   The encoder has to invent both the record fill and the blob fill. Budget it as w1's hardest
+   row, not as one of the easy `kHasBlob` eight.
+
+7. **Three of the brief's 19 have no applier entry point at all** — `SetShaderBuffers` (38),
+   `SetStreamOutputTargets` (39), `DrawVbo` (59). `scout-premortem:§3` cites
+   `PipeApply.h:756, 941, 1028-1030` for a six-call row; those five citations cover five *other*
+   calls. For these three, "what crosses today" is **nothing**, and P5 writes the first producer
+   *and* the first consumer.
+
+8. **`CreateRenderState` and `SetDynamicState` declare a `Blob.Size` that nothing ever reads.**
+   `scout-wire-codec:§4.2`'s "`Size = 0`" column is stale for four rows (add
+   `CreateVertexElements` and `ResourceSubData`'s buffer half). The applier's only four
+   `Blob.Size` reads are `PipeApply.cpp:702`, `:1998`, `:2353`, `:2784`. A fifth
+   flags-vs-payload-vs-signature disagreement for the reviewer's list.
+
+9. **The emit table is 71 function pointers, not 69.** R-4 says 69 slots; that is
+   `GLFunctionsTable`'s count. The table the client actually installs is
+   `GlobalBackendFunctionsTable` = 69 + `Present` + `SetSwapInterval`. R-4's rule (no null slot,
+   no pass-through) applies to all 71, and `Present` is on the reduced path. The Bool member is
+   not a verb and is answered from `kCapCpuXfbPrimitiveAccounting`.
+
+10. **`prefersCpuXfbPrimitiveAccounting` is a member of `GLFunctionsTable`
+    (`BackendObject.h:274`), not of `DynamicBackendParameters`.** So it does **not** ride inside
+    `MGPCaps::Dynamic`, and R-8's "same redundancy as (6)" is the wrong frame — it has three
+    spellings and no carrier in `MGPCaps` except the cap bit. Its one non-test client reader is
+    `GL_Query.cpp:221`.
+
+11. **The persistent-map census is 21 sites, and `MEASUREMENTS.md:111`'s 20 is wrong.** Ruling
+    and the missing site named above. **`ARCHITECTURE.md`'s cited "§5.7" attribution table does
+    not exist in the tree.**
+
+12. **`ScopedDefaultUnpackState` has six value shadows, not five** (`Managers.cpp:5491-5496`);
+    both the brief and the scout say five.
+
+13. **`CanTouchGLNow()` guards 16 call sites, not 19.** 19 is the raw grep: 1 definition
+    (`Managers.cpp:928`) + 2 comment mentions (`:1967`, `:1979`) + 16 calls. The brief's "19
+    sites" over-counts. `IsBackendContextCurrentOnThisThread`'s 16 is right.
+
+14. **`MGPipeApply*` is 37 entry points and 41 call sites**, not "~45 entry points" — and
+    `DirectGLES.cpp:12446` is `Present()`'s fence poll, **not** `ClampSamplesToBackendSupport`
+    (which is `BackendObject_DirectGLES.cpp:807-828`). Table 3's `pActiveBackendObject` row is
+    still correct but the diff is six functions, not one line.
+
+15. **The 18 `build-split` unit aborts are not a poison problem.** They are
+    `Fatal{ProtocolCorruption}` trip wires the tests *expect*; seven test TUs test
+    `MOBILEGL_PIPE_POISON` without including the only header that defines it, so the macro reads
+    as 0 and they compile the "logs and carries on" arm while `PipeApply.cpp` compiles the
+    aborting one. Invisible in a push build (where it really is 0) and in a verify build (where
+    `-DMOBILEGL_PIPE_VERIFY=1` is on the command line); `MOBILEGL_BUILD_DISAGGREGATED` is the one
+    arming condition behind the header. Fixed in c0's own commit, test-local, no p1 surface.
+
+16. **`MGHostSpan`, not `MGPHostSpan`.** The header is `MGPipeHostSpan.h`; the struct is
+    `MGHostSpan` (`:28`). `MGPHostSpan` does not exist.
+
+17. **`ARCHITECTURE.md`'s own corrections, carried here so they are not lost**: `:83` says 61
+    `PipeInputs` fields, it is 63; `:492` cites `PipeStats.h:126` for
+    `MapPersistentRoundtrips`, it is `:141`; ROADMAP's P4a row says six
+    `MGPipeUnmigratedEmulation` sites, it is five calls plus one comment; `ARCHITECTURE.md:19`
+    says eight EGL lifecycle virtuals, there are nine (`ResizeEGLWindowSurface` is the
+    uncounted one).
+
+---
+
+## §7 R-15 — getter-shaped slots are answered locally, and the emit table's three classes
+
+**R-15 (integrator ruling, made after the verb census).** A `GLFunctionsTable` slot whose answer
+is a **static property of the server's device** is answered on the client **from the caps
+mirror**. It is never emitted and never `Fatal`. The gate already exists and already runs on
+every lane: `AdvertisedLimitsScenario.ComputeWorkGroupLimitsAreTheCapsBlocksAnswer`
+(`MG_IntegrationTest/Scenarios/AdvertisedLimitsScenario.cpp:580-623`) pins that the caps copy and
+`glGetIntegeri_v` give one number.
+
+This settles the census's sharpest finding: `GetIntegeri_v` is reached by the **first
+`glCompileShader` of every context** (`CompileEnv.cpp:134-138` ← `Core.cpp:39`), not by any verb,
+so an all-`Fatal` table would abort every scenario before it drew anything — and an emitter for
+it would be a round trip for six constants the snapshot already carries.
+
+### The three classes of the 71 slots. c1 does not re-derive this.
+
+**Class A — answered locally from the caps mirror (2 slots). No record, ever.**
+
+| slot | answered from |
+|---|---|
+| `GetIntegeri_v` (`BackendObject.h:205`) | `MGPCaps::Dynamic.MaxComputeWorkGroupCount` / `MaxComputeWorkGroupSize` (`BackendObject.h:392-393`) — the only indexed pnames the device owns. Every other indexed pname is frontend state and is answered before any table is consulted. |
+| `IsTimerQuerySupported` (`:245`) | `kCapTimerQuery` (`MGPipeTypes.h:114`). A capability predicate, not a call: today a null slot means `COUNTER_BITS = 0` (`GL_Query.cpp:792`). |
+
+`GLFunctionsTable::PrefersCpuXfbPrimitiveAccounting` (`:274`) is in the same class by the same
+argument — `kCapCpuXfbPrimitiveAccounting` — and is not a slot.
+
+**Class B — emitted in P5 (5 slots).** The verb census's answer, and nothing else:
+`Clear`, `DrawArrays`, `ReadPixels`, `BlitFramebuffer`, `Present`.
+`Present` is in this class despite having **zero `MG_Impl` call sites** — it is reached through
+`EGLImpl.cpp:178` → `BackendObject.cpp:396`, so c1 cannot find it by mirroring GLImpl.
+
+**Class C — `Fatal{UnmigratedVerb, "<slot>"}` (64 slots).** Everything else, including
+`SetSwapInterval`, `GetGpuTimestampNs` (a live GPU timestamp, not a static property, so **not**
+class A), and the whole sync / query / transform-feedback / compute / copy / mipmap surface.
+
+### The cross-cutting rule R-4 would otherwise break
+
+**Forty-one of the 69 slots are null-checked at their call site, and several of those null checks
+are CAPABILITY PROBES rather than safety checks.** R-4 forbids a null slot — so in the emit table
+every one of those probes answers "supported" and the fallback behind it silently disappears.
+That is not a theoretical risk: it is how a split lane produces a plausible picture for the wrong
+reason. Three named cases; the rule generalises to all 41.
+
+| probe site | what it decides today | reads instead |
+|---|---|---|
+| `GL_Query.cpp:481`, `:785` — `BeginOcclusionQuery != nullptr` | whether the target is rejected outright | `kCapOcclusionQuery` |
+| `GL_Query.cpp:534` — the `BeginXfbPrimitivesQuery` ternary | GPU query vs CPU primitive accounting | `kCapXfbPrimitivesQuery` |
+| the `SubDataResident` op-table slot | whether the resident-upload path exists at all | `kCapResidentSubData` |
+
+**A null check on a slot may never survive into the client under split.** It becomes a caps-mirror
+read — class A's mechanism — whatever class the slot itself is in. That is exactly
+`ARCHITECTURE.md:114`'s "`CallMask` replaces 'is this table slot null' as the implicit capability
+probe", now with a concrete list of what has to move.
+
+---
+
+## §8 Ownership amendments
+
+- **`MobileGL/MG_Pipe/MGPipeTypes.h` is c0's file** (integrator ruling A; the BRIEF §5 ownership
+  table is amended). It was unowned, which is how the respecify-scope gap in table 1 row 19b had
+  no one to close it. A package that needs a payload struct shape changed goes through the
+  integrator, as with the three `.def` files.
+- Consequently the row-19b carrier is **landed, not merely specified** — see §2 table 1 row 19b
+  and `MGPipeTypes.h`'s `HasRespecifiedLevel` / `RespecifiedUploadTarget` / `RespecifiedLevel`
+  and the five `MGPipeRespecify*` helpers beside them.
+

MobileGL/MG_Remote/CapsCodec.cpp

@@ -0,0 +1,56 @@
+// MobileGL - MobileGL/MG_Remote/CapsCodec.cpp
+// Copyright (c) 2025-2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+
+#include "CapsCodec.h"
+
+#include <MG_Util/Debug/Log.h>
+
+#include <cstdlib>
+
+namespace MobileGL::MG_Remote {
+
+    // The consumer mask may not collide with the MGPCapBits below it. kCapNeedsHostUboBytes
+    // is 1<<8 today; this asserts the gap stays a gap rather than trusting the comment.
+    static_assert((static_cast<Uint64>(MG_Pipe::kCapNeedsHostUboBytes) & kMGCapsConsumerMask) == 0,
+                  "an MGPCapBit has grown into CallMask's consumer block (bits 32..47)");
+    static_assert(MGCapsServerConsumes(MGCapsConsumerBits(MG_Pipe::kMGPipeSubsystemResources),
+                                       MG_Pipe::kMGPipeSubsystemResources),
+                  "the consumer encoding does not round-trip");
+    static_assert(!MGCapsServerConsumes(MGCapsConsumerBits(MG_Pipe::kMGPipeSubsystemResources),
+                                        MG_Pipe::kMGPipeSubsystemPrograms),
+                  "the consumer encoding answers yes for a family it was not given");
+    // P4a's highest allocated subsystem bit must fit the sixteen-bit block. This is the
+    // assertion that turns "room to P8" from a comment into a build break.
+    static_assert(MG_Pipe::kMGPipeSubsystemsMigratedAtP4a <= 0xFFFFull,
+                  "the subsystem mask no longer fits CallMask's sixteen consumer bits");
+
+#define MGP5_C0_STUB(what)                                                                                             \
+    do {                                                                                                               \
+        MGLOG_F("MGPipe: Fatal{UnimplementedCapsCodec, \"%s\"} - P5 package w1 has not landed "                        \
+                "this yet; c0 shipped the signature only",                                                             \
+                what);                                                                                                 \
+        std::abort();                                                                                                  \
+    } while (0)
+
+    Bool EncodeFormatCapabilities(const MG_Backend::FormatCapabilityCache&, Vector<Uint8>&) {
+        MGP5_C0_STUB("EncodeFormatCapabilities");
+    }
+
+    Bool DecodeFormatCapabilities(const void*, Uint64, MG_Backend::FormatCapabilityCache&) {
+        MGP5_C0_STUB("DecodeFormatCapabilities");
+    }
+
+    Bool EncodeRendererInfo(const RendererInfo&, Vector<Uint8>&) { MGP5_C0_STUB("EncodeRendererInfo"); }
+
+    Bool DecodeRendererInfo(const void*, Uint64, RendererInfo&) { MGP5_C0_STUB("DecodeRendererInfo"); }
+
+    Uint64 CapsAbiFingerprint() { MGP5_C0_STUB("CapsAbiFingerprint"); }
+
+#undef MGP5_C0_STUB
+
+} // namespace MobileGL::MG_Remote

MobileGL/MG_Remote/CapsCodec.h

@@ -0,0 +1,99 @@
+// MobileGL - MobileGL/MG_Remote/CapsCodec.h
+// Copyright (c) 2025-2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+
+// The MGPCaps snapshot's serializers, and the CallMask encoding. Owner: package w1 (the two
+// blob codecs) and s1 (the handshake asserts). Signatures by c0.
+//
+// MGPCaps (MG_Pipe/MGPipeTypes.h:126-139) has four members. Two are flat and cross by memcpy
+// (DynamicBackendParameters Dynamic, Uint64 CallMask); two are MGPBlobRefs over containers
+// and HAVE NO SERIALIZER IN THE TREE - the header says so itself at MGPipeTypes.h:134-136,
+// "Their serializers land with the transport (P5)". They are:
+//
+//   FormatCapabilities -> FormatCapabilityCache (MG_Backend/BackendObject.h:93-98):
+//       FullCaps + CaveatCaps (bitfield tables) + SampleCounts, a Vector<Int> per
+//       (target, format) pair. The Vector is why this cannot be a memcpy.
+//   RendererInfo       -> RendererInfo (MG_Util/Types.h:317): three Strings, an
+//       Optional<String>, and a Vector<GLExtension> inside GLInfo.
+//
+// THE ABI RULING (table 0). MGPCaps has only a COMPOSITIONAL size assertion
+// (MGPipeTypes.h:145-146) because DynamicBackendParameters still carries SizeT and GLenum
+// members - P0.5's fixed-width rewrite did not happen. P5 does NOT rewrite it. Instead the
+// handshake asserts that both peers agree on sizeof(DynamicBackendParameters),
+// sizeof(MGPCaps) and the build fingerprint, and Fatal{AbiMismatch} otherwise. P6's spawn is
+// same-machine and same-binary, so it inherits this unchanged; the fixed-width rewrite is on
+// P7's account.
+
+#pragma once
+#include <Includes.h>
+
+#include <MG_Backend/BackendObject.h>
+#include <MG_Pipe/MGPipe.h>
+
+namespace MobileGL::MG_Remote {
+
+    // ---- CallMask's layout (c0's ruling, extending R-8) ---------------------------------
+    //
+    // R-8 requires the client's liveness gates - MGPipeResourceSubsystemEnabled() and
+    // P4aFamilyHasItsConsumer() - to answer from MGPCaps::CallMask instead of from
+    // MGPipeGetResourceOps(), because that op table is the SERVER's registration: under
+    // inproc a client reading it is right by accident, and under spawn it is null and five
+    // whole record families silently emit nothing.
+    //
+    // But CallMask as declared carries only the nine MGPCapBit FEATURE bits
+    // (MGPipeTypes.h:108-124) and has no per-family bit at all, so "read the CallMask" was
+    // not yet an implementable instruction. It is now:
+    //
+    //   bits  0..8   MGPCapBit, unchanged. kCapNeedsHostIndexBytes and kCapNeedsHostUboBytes
+    //                are BOTH ZERO in P5 by ruling (table 0), which is what keeps every
+    //                MGHostSpan out of the first IPC frame.
+    //   bits  9..31  reserved for further MGPCapBits.
+    //   bits 32..47  THE CONSUMER MASK: bit (32 + n) means "the server has a consumer for
+    //                MGPipe subsystem bit n" - i.e. the server's own subsystem mask, shifted.
+    //                Sixteen bits covers bits 0..12 allocated through P4a with room to P8.
+    //   bits 48..63  reserved.
+    //
+    // protocol.fbs:94's `tableSlotMask: ulong` is DELETED rather than renamed (R-8 offered
+    // either). Two reasons, and the second is decisive: ARCHITECTURE.md:114 says CallMask
+    // REPLACES "is this table slot null" as the capability probe, so a field whose comment is
+    // "which GLFunctionsTable slots the peer registered" re-introduces exactly what it
+    // replaced; and GLFunctionsTable has SIXTY-NINE function-pointer slots
+    // (BackendObject.h:117-292), so a 64-bit mask cannot address it and never could.
+    inline constexpr Uint32 kMGCapsConsumerBitShift = 32;
+    inline constexpr Uint64 kMGCapsConsumerMask = 0xFFFFull << kMGCapsConsumerBitShift;
+
+    // Server side: fold the subsystems this server actually consumes into a CallMask.
+    inline constexpr Uint64 MGCapsConsumerBits(Uint64 subsystemMask) {
+        return (subsystemMask & 0xFFFFull) << kMGCapsConsumerBitShift;
+    }
+
+    // Client side: the ONE legal spelling of "does the server consume this family".
+    // `subsystemBit` is a kMGPipeSubsystem* constant (MG_Pipe/MGPipe.h), not an index.
+    inline constexpr Bool MGCapsServerConsumes(Uint64 callMask, Uint64 subsystemBit) {
+        return (callMask & MGCapsConsumerBits(subsystemBit)) != 0;
+    }
+
+    // ---- the two blob codecs ------------------------------------------------------------
+    //
+    // Byte-stable within one build; the handshake's fingerprint is what makes that enough.
+    // Both decoders must tolerate a truncated or over-long buffer by returning false, never
+    // by reading past `size`: these bytes arrive over the wire.
+    Bool EncodeFormatCapabilities(const MG_Backend::FormatCapabilityCache& cache, Vector<Uint8>& out);
+    Bool DecodeFormatCapabilities(const void* bytes, Uint64 size, MG_Backend::FormatCapabilityCache& out);
+
+    Bool EncodeRendererInfo(const RendererInfo& info, Vector<Uint8>& out);
+    Bool DecodeRendererInfo(const void* bytes, Uint64 size, RendererInfo& out);
+
+    // ---- the ABI assertion the handshake carries ----------------------------------------
+    //
+    // Mixes sizeof(DynamicBackendParameters), sizeof(MGPCaps), sizeof(GLFunctionsTable) and
+    // the compile-time build fingerprint. Compared in Hello/Welcome; a mismatch is
+    // Fatal{AbiMismatch} and never a downgrade, because every alternative silently reads one
+    // struct as another.
+    Uint64 CapsAbiFingerprint();
+
+} // namespace MobileGL::MG_Remote

MobileGL/MG_Remote/Client/CapsMirror.cpp

@@ -0,0 +1,63 @@
+// MobileGL - MobileGL/MG_Remote/Client/CapsMirror.cpp
+// Copyright (c) 2025-2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+
+// P5 c0 stubs for package c1. Every body is MGLOG_F + std::abort and never a silent no-op: a
+// caps accessor that answers a default is how a split lane runs on the wrong device's limits.
+
+#include "CapsMirror.h"
+
+#include <MG_Util/Debug/Log.h>
+
+#include <cstdlib>
+
+namespace MobileGL::MG_Remote::Client {
+
+#define MGP5_C0_STUB(what)                                                                                             \
+    do {                                                                                                               \
+        MGLOG_F("MGPipe: Fatal{UnimplementedCapsMirror, \"%s\"} - P5 package c1 has not landed "                       \
+                "this yet; c0 shipped the signature only",                                                             \
+                what);                                                                                                 \
+        std::abort();                                                                                                  \
+    } while (0)
+
+    void CapsMirror::Adopt(const MG_Pipe::MGPCaps&, const MG_Backend::FormatCapabilityCache&,
+                           const RendererInfo&, const String&, BackendType) {
+        MGP5_C0_STUB("CapsMirror::Adopt");
+    }
+
+    // Not stubs: the two the placeholder contract above promises are readable before the first
+    // snapshot. Everything else aborts, so nothing can accidentally answer from a zeroed mirror.
+    Bool CapsMirror::Valid() const { return m_generation != 0; }
+    Uint64 CapsMirror::Generation() const { return m_generation; }
+
+    const RendererInfo& CapsMirror::Renderer() const { MGP5_C0_STUB("CapsMirror::Renderer"); }
+    const MG_Backend::DynamicBackendParameters& CapsMirror::Dynamic() const {
+        MGP5_C0_STUB("CapsMirror::Dynamic");
+    }
+    const MG_Backend::FormatCapabilityCache& CapsMirror::Formats() const {
+        MGP5_C0_STUB("CapsMirror::Formats");
+    }
+    const String& CapsMirror::ApiVersion() const { MGP5_C0_STUB("CapsMirror::ApiVersion"); }
+    BackendType CapsMirror::Backend() const { MGP5_C0_STUB("CapsMirror::Backend"); }
+    Uint64 CapsMirror::CallMask() const { MGP5_C0_STUB("CapsMirror::CallMask"); }
+    Bool CapsMirror::HasCap(MG_Pipe::MGPCapBit) const { MGP5_C0_STUB("CapsMirror::HasCap"); }
+    Bool CapsMirror::ServerConsumes(Uint64) const { MGP5_C0_STUB("CapsMirror::ServerConsumes"); }
+    Bool CapsMirror::PrefersCpuXfbPrimitiveAccounting() const {
+        MGP5_C0_STUB("CapsMirror::PrefersCpuXfbPrimitiveAccounting");
+    }
+
+    CapsMirror& CapsMirrorInstance() {
+        // ID-8: leak at exit. No frontend destructor may reach pipe or backend state from an
+        // exit handler, and that rule applies once per role-local singleton, not once overall.
+        static CapsMirror& instance = *new CapsMirror{};
+        return instance;
+    }
+
+#undef MGP5_C0_STUB
+
+} // namespace MobileGL::MG_Remote::Client

MobileGL/MG_Remote/Client/CapsMirror.h

@@ -0,0 +1,100 @@
+// MobileGL - MobileGL/MG_Remote/Client/CapsMirror.h
+// Copyright (c) 2025-2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+
+// The client's copy of the server's capabilities. Owner: package c1. Signatures by c0.
+//
+// WHY A MIRROR AND NOT A ROUND TRIP. There are 56 client-side caps read points
+// (40 GetDynamicParameters + 7 GetRendererInfo + 4 GetFormatCapabilities + 3 GetBackendType +
+// 2 GetBackendAPIVersionString), and several of them - GL_Getter.cpp:2400 and
+// ShaderTranspiler/CompileEnv.cpp:120-124 - bind a reference and then read many members, so a
+// partial snapshot is not an option. Every one of the 56 must be answerable locally, with no
+// record on the wire.
+//
+// GetRendererInfo() RETURNS A REFERENCE (BackendObject.h:590), so the mirror must OWN a
+// RendererInfo instance to hand back - including before the first snapshot arrives, because
+// LogBackendInfo() reads it at MG_Backend/Init.cpp:21, during MG_Backend::Init(), long before
+// any context exists. Ruling (scout-caps-reply §1.2 option (a)): the mirror answers with a
+// placeholder until the first snapshot, P5 accepts one inaccurate startup log line, and
+// MG_Backend::Init() is NOT restructured.
+//
+// GetFormatCapabilities() is NON-VIRTUAL (BackendObject.h:594), so a remote backend object
+// cannot override the accessor: it must FILL BackendObject::m_formatCapabilities from this
+// mirror instead.
+//
+// INVALIDATION IS RE-ARRIVAL (R-12). DirectGLES has no OnCapsInvalidated producer at all - it
+// re-runs UpdateAdvertisedCapabilityExtensions + UpdateDynamicBackendParameters at
+// BackendObject_DirectGLES.cpp:865-871 and tells the frontend nothing, which is correct in
+// monolith and a silent bug under split. Rather than add a DirectGLES-side callback (a
+// dev-shaped backend edit), the SERVER re-sends the whole snapshot on every InitCapabilities
+// re-run and the CLIENT treats a second arrival as the invalidation. Generation() is what a
+// client-side memo keys on, and it is also the re-open signal for the server-context-death
+// case that MGPipeCallbacks has no eleventh slot for (MGPipeCallbacks.h:56-58).
+
+#pragma once
+#include <Includes.h>
+
+#include <MG_Backend/BackendObject.h>
+#include <MG_Pipe/MGPipe.h>
+
+namespace MobileGL::MG_Remote::Client {
+
+    class CapsMirror {
+    public:
+        // Replaces the whole mirror and bumps Generation(). Called once per CapsSnapshot,
+        // including the re-sends that mean "invalidate" (R-12).
+        void Adopt(const MG_Pipe::MGPCaps& caps, const MG_Backend::FormatCapabilityCache& formats,
+                   const RendererInfo& renderer, const String& apiVersion,
+                   BackendType backend);
+
+        // False until the first snapshot. The placeholder answers below are still safe to
+        // read - that is the point - but a caller that can wait should.
+        Bool Valid() const;
+
+        // ++ on every Adopt. A client memo that survives a server context loss must key on
+        // this; nothing else on the client can see that the server's context died.
+        Uint64 Generation() const;
+
+        const RendererInfo& Renderer() const;
+        const MG_Backend::DynamicBackendParameters& Dynamic() const;
+        const MG_Backend::FormatCapabilityCache& Formats() const;
+        const String& ApiVersion() const;
+        // The SERVER's backend type, never a new "Remote" enumerator: frontend branches
+        // switch on this (GL_Framebuffer.cpp:47, GL_Texture.cpp:6536, CompileEnv.cpp:122) and
+        // a value they do not know silently takes the wrong arm.
+        BackendType Backend() const;
+
+        Uint64 CallMask() const;
+        Bool HasCap(MG_Pipe::MGPCapBit bit) const;
+
+        // R-8. `subsystemBit` is a kMGPipeSubsystem* constant. THIS IS THE ONLY LEGAL SOURCE
+        // of the answer on the client under split: MGPipeGetResourceOps() is the SERVER's
+        // registration and is null in the client process, which would silently disable the
+        // whole push path in the one mode that matters.
+        Bool ServerConsumes(Uint64 subsystemBit) const;
+
+        // GLFunctionsTable::PrefersCpuXfbPrimitiveAccounting (BackendObject.h:274) does NOT
+        // ride in MGPCaps::Dynamic - it is a member of the function table, which is precisely
+        // the thing a split client never receives. Its only non-test client reader is
+        // GL_Query.cpp:221, and under split it must be answered from kCapCpuXfbPrimitiveAccounting.
+        Bool PrefersCpuXfbPrimitiveAccounting() const;
+
+    private:
+        MG_Pipe::MGPCaps m_caps{};
+        MG_Backend::FormatCapabilityCache m_formats{};
+        RendererInfo m_renderer{};
+        String m_apiVersion;
+        BackendType m_backend = BackendType::Unknown;
+        Uint64 m_generation = 0;
+    };
+
+    // Per client context in principle; one per process in P5, because P5 serves one context.
+    // Leak-at-exit like every other MG_Remote singleton (ID-8): no frontend destructor may
+    // reach pipe or backend state from an exit handler.
+    CapsMirror& CapsMirrorInstance();
+
+} // namespace MobileGL::MG_Remote::Client

MobileGL/MG_Remote/Client/ClientSession.cpp

@@ -0,0 +1,56 @@
+// MobileGL - MobileGL/MG_Remote/Client/ClientSession.cpp
+// Copyright (c) 2025-2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+
+// P5 c0 stubs for packages s1 (construction, handshake) and c1 (barrier, reply read).
+
+#include "ClientSession.h"
+
+#include <MG_Util/Debug/Log.h>
+
+#include <cstdlib>
+
+namespace MobileGL::MG_Remote::Client {
+
+#define MGP5_C0_STUB(what)                                                                                             \
+    do {                                                                                                               \
+        MGLOG_F("MGPipe: Fatal{UnimplementedClientSession, \"%s\"} - P5 packages s1/c1 have not "                      \
+                "landed this yet; c0 shipped the signature only",                                                      \
+                what);                                                                                                 \
+        std::abort();                                                                                                  \
+    } while (0)
+
+    // Null, not a Fatal: MG_Backend::Init() asks whether a session exists before it decides to
+    // install the remote backend object, and that question has a legitimate "no" - it is the
+    // monolith answer. Every call that PRESUMES a session aborts instead.
+    ClientSession* ClientSession::Active() { return nullptr; }
+
+    MobileGLResult ClientSession::Start(MG_Config::TransportMode, const String&) {
+        MGP5_C0_STUB("ClientSession::Start");
+    }
+
+    void ClientSession::Stop() { MGP5_C0_STUB("ClientSession::Stop"); }
+
+    Wire::PipeWireEncoder& ClientSession::Encoder() { return m_encoder; }
+
+    CapsMirror& ClientSession::Caps() { return CapsMirrorInstance(); }
+
+    Uint64 ClientSession::EmitAndWait(MG_Pipe::MGPWireOp, const void*, Uint64, const void*, Uint64,
+                                      void*, Uint64, Int32*) {
+        MGP5_C0_STUB("ClientSession::EmitAndWait");
+    }
+
+    Bool ClientSession::BarrierArmed() const { return m_barrierArmed; }
+
+    // False, not a Fatal, for both: these are the R-1 mutual-exclusion assertion's two probes,
+    // and an assertion helper that aborts when asked is worse than useless.
+    Bool ClientSession::InBarrierWait() { return false; }
+    Bool ClientSession::ApplyThreadIsInsideApplier() { return false; }
+
+#undef MGP5_C0_STUB
+
+} // namespace MobileGL::MG_Remote::Client

MobileGL/MG_Remote/Client/ClientSession.h

@@ -0,0 +1,95 @@
+// MobileGL - MobileGL/MG_Remote/Client/ClientSession.h
+// Copyright (c) 2025-2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+
+// The client half of a session: the rings, the handshake, the verb barrier. Owner: package s1
+// (construction and handshake) with c1 (the barrier and the reply read). Signatures by c0.
+//
+// INPROC USES ShmSegment AND THE RING, NOT new[] AND NOT InProcessTransport's deques. That is
+// half of what "inproc runs the same G3 codec as spawn" means: InProcessTransport
+// (InProcessTransport.cpp:38-97) is two deque<vector<uint8_t>> plus two condvar doorbells, it
+// touches neither a ring nor a codec, and building the session on top of it instead of on top
+// of the ring would make the whole phase unfalsifiable. The transport supplies the two
+// DOORBELLS and the control plane; the records go through SEG_CMD.
+//
+// THE VERB BARRIER (R-1). After emitting a verb the client blocks until
+// RingControl::appliedSeq >= the seq it just got back from the encoder. It is not caution: 31
+// of the 63 PipeInputs fields are still filled by the client's residual pass out of a live
+// GLContext, so an unbarriered queue lets the server read a FUTURE value of them. Two
+// consequences that must be stated because both are load-bearing:
+//   - while the barrier holds, at most one of {GL thread, apply thread} is runnable, which is
+//     what makes a single process-wide gPipeInputs legal (table 3);
+//   - the barrier is a RETIRING object, not a design. It opens family by family as table 2's
+//     BARRIER-PULLED column empties, and each later package reports how many rows it left.
+//
+// THE BARRIER'S WAIT IS ALSO THE REPLY'S WAIT (R-3/R-5). The reply slot id IS the record seq,
+// so "wait for appliedSeq >= mySeq" and "wait for my answer" are one wait and the four Bool
+// acceptance returns, ReadPixels' pixels and MapPersistent's decline cost ZERO extra round
+// trips. The client MUST NOT re-derive any of those four answers locally - that is the c0f/c0g
+// defect P4a paid two contract corrections for, and "always accept" is ID-39's 66 lost uploads.
+
+#pragma once
+#include <Includes.h>
+
+#include <Config.h>
+#include <MG_Pipe/MGPipe.h>
+
+#include "../Wire/PipeWireCodec.h"
+#include "CapsMirror.h"
+
+namespace MobileGL::MG_Remote::Client {
+
+    class ClientSession {
+    public:
+        // Null until Start() succeeds; MG_Backend::Init() is the only caller of Start().
+        static ClientSession* Active();
+
+        // Builds the four segments, performs Hello/Welcome, takes the first CapsSnapshot, and
+        // - for TransportMode::InProcess - starts the server role's apply thread. Returns a
+        // named error rather than falling back to monolith: a fallback here is the "split lane
+        // ran monolith and went green" failure, and it must be loud.
+        MobileGLResult Start(MG_Config::TransportMode mode, const String& endpoint);
+
+        // Teardown order matters and is table 3's fourth column: publish and let the server
+        // drain, Doorbell::Kill() (the ONLY thing that wakes an apply thread parked on
+        // kWaitForever, Doorbell.h:211-221), then join, and only then release anything an
+        // emitter owns - a tail still referenced by an unapplied record is a use-after-free
+        // the join is what prevents.
+        void Stop();
+
+        Wire::PipeWireEncoder& Encoder();
+        CapsMirror& Caps();
+
+        // Emit one record and, if the barrier is armed, wait for it. `replyOut`/`replyBytes`
+        // name where a kReplySlot answer lands; pass {nullptr, 0} for a call that has none.
+        // Returns the record's seq, which is also its reply-slot id.
+        //
+        // Waiting is spin(MOBILEGL_IPC_SPIN_US) then park, through Doorbell::Wait, with
+        // producerParked set before blocking - the shape Doorbell.h:121 already implements.
+        Uint64 EmitAndWait(MG_Pipe::MGPWireOp op, const void* payload, Uint64 payloadBytes,
+                           const void* varTail, Uint64 varTailBytes, void* replyOut,
+                           Uint64 replyBytes, Int32* statusOut);
+
+        // MOBILEGL_IPC_VERB_BARRIER. False is the R-1 negative control and is EXPECTED to be
+        // red; it must be run once and the way it goes red recorded.
+        Bool BarrierArmed() const;
+
+        // R-1's invariant made checkable rather than only written down: true while this
+        // thread is inside a barrier wait. The apply thread sets its own flag on entry to the
+        // applier; a debug/verify build asserts the two are never both true, and that the
+        // client never touches gPipeInputs while the server is inside the applier.
+        static Bool InBarrierWait();
+        static Bool ApplyThreadIsInsideApplier();
+
+    private:
+        Wire::PipeWireEncoder m_encoder;
+        Wire::SegmentTable m_segments;
+        CapsMirror* m_caps = nullptr;
+        Bool m_barrierArmed = true;
+    };
+
+} // namespace MobileGL::MG_Remote::Client

MobileGL/MG_Remote/Client/EmitTables.cpp

@@ -0,0 +1,47 @@
+// MobileGL - MobileGL/MG_Remote/Client/EmitTables.cpp
+// Copyright (c) 2025-2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+
+// P5 c0 stubs for package c1.
+
+#include "EmitTables.h"
+
+#include <MG_Util/Debug/Log.h>
+
+#include <cstdlib>
+
+namespace MobileGL::MG_Remote::Client {
+
+    // The slot arithmetic, asserted rather than commented. GlobalBackendFunctionsTable is
+    // GLFunctionsTable plus Present plus SetSwapInterval; GLFunctionsTable is 69 function
+    // pointers plus one Bool (PrefersCpuXfbPrimitiveAccounting, BackendObject.h:274). A slot
+    // added to either without a decision here is a build break, which is the point: R-4 forbids
+    // a null slot, so a new slot needs an owner on the day it appears.
+    static_assert(sizeof(MG_Backend::GlobalBackendFunctionsTable) ==
+                      sizeof(MG_Backend::GLFunctionsTable) + 2 * sizeof(void (*)()),
+                  "GlobalBackendFunctionsTable is no longer GLFunctionsTable + Present + SetSwapInterval");
+    static_assert(sizeof(MG_Backend::GlobalBackendFunctionsTable) ==
+                      kRemoteEmitSlotCount * sizeof(void (*)()) + sizeof(void (*)()),
+                  "the emit table's 71 slots plus the packed Bool no longer describe the table");
+
+    [[noreturn]] void UnmigratedVerbFatal(const char* slot) {
+        // The same shape as MGPipeInputPoisonFatal (generated/PipeFilled.inc:407-413): names the
+        // slot, live at every log level, aborts. Deliberately NOT MOBILEGL_ASSERT, which is
+        // inert in an INFO build - and INFO is what every device lane runs.
+        MGLOG_F("MGPipe: Fatal{UnmigratedVerb, \"%s\"}", slot);
+        std::abort();
+    }
+
+    const MG_Backend::GlobalBackendFunctionsTable& RemoteEmitTable() {
+        MGLOG_F("MGPipe: Fatal{UnimplementedEmitTable, \"RemoteEmitTable\"} - P5 package c1 has "
+                "not landed this yet; c0 shipped the signature only");
+        std::abort();
+    }
+
+    Uint32 ImplementedVerbCount() { return 0; }
+
+} // namespace MobileGL::MG_Remote::Client

MobileGL/MG_Remote/Client/EmitTables.h

@@ -0,0 +1,80 @@
+// MobileGL - MobileGL/MG_Remote/Client/EmitTables.h
+// Copyright (c) 2025-2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+
+// The client's emitting function table. Owner: package c1. Signatures by c0.
+//
+// MG_Backend/Init.cpp:44 assigns gBackendFunctionsTable from the active backend object, and
+// 91 MG_Impl/GLImpl sites call through it directly. So a BackendObject_Remote has to return a
+// COMPLETE table, and "complete" is a bigger number than R-4's headline:
+//
+//   GLFunctionsTable                (BackendObject.h:117-292) = 69 function pointers
+//                                                             + Bool PrefersCpuXfbPrimitiveAccounting
+//   GlobalBackendFunctionsTable     (BackendObject.h:293-299) = the above, + Present, + SetSwapInterval
+//                                                             = 71 function pointers in total
+//
+// R-4's rule, restated over all 71: NO SLOT MAY BE NULL, and no slot may fall through to a
+// driver. A null slot is 91 potential null calls; a pass-through slot is a split lane quietly
+// running monolith and going green, which is the one outcome every gate in this phase exists
+// to prevent. A verb P5 does not implement gets a slot that raises
+// Fatal{UnmigratedVerb, "<slot>"} - the same shape as MGPipeInputPoisonFatal, live at every
+// log level, MGLOG_F + std::abort.
+//
+// WHICH SLOTS GET A REAL EMITTER IS DECIDED BY THE VERB CENSUS (R-4), not guessed here:
+// ~/w7/notes/p5/verb-census.md. CONTRACT-P5.md §7 carries the resulting THREE-CLASS SPLIT and
+// it is not to be re-derived:
+//
+//   A. ANSWERED LOCALLY from the caps mirror, never emitted and never Fatal (R-15) - two
+//      slots, GetIntegeri_v and IsTimerQuerySupported, plus the Bool member
+//      PrefersCpuXfbPrimitiveAccounting, which is not a slot. GetIntegeri_v is the one that
+//      would otherwise sink the phase: it is reached by the FIRST glCompileShader of every
+//      context (CompileEnv.cpp:134-138 <- Core.cpp:39), not by any verb, so a Fatal there
+//      aborts every scenario before it draws anything.
+//   B. EMITTED in P5 - five slots: Clear, DrawArrays, ReadPixels, BlitFramebuffer, Present.
+//      Present has ZERO MG_Impl call sites: it is reached through EGLImpl.cpp:178 ->
+//      BackendObject.cpp:396, so mirroring GLImpl will not find it.
+//   C. Fatal{UnmigratedVerb} - the remaining 64, SetSwapInterval and GetGpuTimestampNs among
+//      them.
+//
+// AND THE RULE R-4 WOULD OTHERWISE BREAK. 41 of the 69 slots are null-checked at their call
+// site, and several of those checks are CAPABILITY PROBES, not safety checks - BeginOcclusionQuery
+// (GL_Query.cpp:481, :785), BeginXfbPrimitivesQuery (:534), SubDataResident. With no null slot
+// in this table every one of them answers "supported" and the fallback behind it silently
+// disappears. A null check on a slot may not survive into the client: it becomes a caps-mirror
+// read, which is what ARCHITECTURE.md:114 means by "CallMask replaces 'is this table slot null'".
+//
+// NOTE the asymmetry this table does not resolve: the resource, CSO, framebuffer, texture,
+// sampler and program families do NOT come through here. They are emitted from
+// MG_Impl/Pipe/* by direct MGPipeApply* calls (37 entry points, 41 call sites), and under
+// split each of those becomes an encode. This table covers only the verbs - the draws,
+// clears, blits, readbacks, queries, fences and present.
+
+#pragma once
+#include <Includes.h>
+
+#include <MG_Backend/BackendObject.h>
+
+namespace MobileGL::MG_Remote::Client {
+
+    // The table MG_Backend::Init() installs into gBackendFunctionsTable for the remote role.
+    // A reference to a never-destroyed block, like every other MG_Remote singleton (ID-8).
+    const MG_Backend::GlobalBackendFunctionsTable& RemoteEmitTable();
+
+    // Called by the Fatal slots. Named separately so a death test can filter on it and so
+    // that the message wording lives in exactly one place.
+    [[noreturn]] void UnmigratedVerbFatal(const char* slot);
+
+    // How many of the 71 slots have a real emitter. Reported at bring-up and asserted by the
+    // gate: a table that silently loses an emitter should not be able to look the same as one
+    // that never had it.
+    Uint32 ImplementedVerbCount();
+
+    // The total the count above is out of. Asserted against the struct in EmitTables.cpp, so
+    // a slot added to GLFunctionsTable without a decision here is a build break.
+    inline constexpr Uint32 kRemoteEmitSlotCount = 71;
+
+} // namespace MobileGL::MG_Remote::Client

MobileGL/MG_Remote/Server/PipeApplier.cpp

@@ -0,0 +1,51 @@
+// MobileGL - MobileGL/MG_Remote/Server/PipeApplier.cpp
+// Copyright (c) 2025-2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+
+// P5 c0 stubs for package v1 (with p1 for the stamp rule).
+
+#include "PipeApplier.h"
+
+#include <MG_Util/Debug/Log.h>
+
+#include <cstdlib>
+
+namespace MobileGL::MG_Remote::Server {
+
+#define MGP5_C0_STUB(what)                                                                                             \
+    do {                                                                                                               \
+        MGLOG_F("MGPipe: Fatal{UnimplementedPipeApplier, \"%s\"} - P5 package v1 has not landed "                      \
+                "this yet; c0 shipped the signature only",                                                             \
+                what);                                                                                                 \
+        std::abort();                                                                                                  \
+    } while (0)
+
+    ReplyPool::ReplyPool(void* base, Uint64 sizeBytes, Uint32 slotCount, Uint32 slotBytes)
+        : m_base(static_cast<Uint8*>(base)), m_size(sizeBytes), m_slots(slotCount), m_slotBytes(slotBytes) {}
+
+    void ReplyPool::PostReply(Uint64, Int32, const void*, Uint64) { MGP5_C0_STUB("ReplyPool::PostReply"); }
+
+    Uint32 ReplyPool::SlotBytes() const { return m_slotBytes; }
+
+    PipeApplier::PipeApplier(Wire::SegmentTable* segments, ReplyPool* replies)
+        : m_segments(segments), m_replies(replies) {}
+
+    Bool PipeApplier::ApplyOne(const Transport::RingRecordView&) { MGP5_C0_STUB("PipeApplier::ApplyOne"); }
+
+    void PipeApplier::StampVerbBoundary(MG_Pipe::MGPWireOp) {
+        MGP5_C0_STUB("PipeApplier::StampVerbBoundary");
+    }
+
+    Uint64 PipeApplier::ResidualPullCount() const { return m_residualPulls; }
+
+    void PipeApplier::PoisonRetiredStageBytes(Uint64, Uint64) {
+        MGP5_C0_STUB("PipeApplier::PoisonRetiredStageBytes");
+    }
+
+#undef MGP5_C0_STUB
+
+} // namespace MobileGL::MG_Remote::Server

MobileGL/MG_Remote/Server/PipeApplier.h

@@ -0,0 +1,102 @@
+// MobileGL - MobileGL/MG_Remote/Server/PipeApplier.h
+// Copyright (c) 2025-2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+
+// The server's applier bridge. Owner: package v1, with p1 for the stamp rule. Signatures by c0.
+//
+// IT IS A BRIDGE, NOT AN APPLIER. The applier already exists and is not edited by this phase:
+// MG_Pipe/PipeApply.{h,cpp}, 37 MGPipeApply* free functions. This class owns the three things
+// that only exist once records arrive over a wire rather than by direct call:
+//
+//   1. THE VERB STAMP. This is the phase's prerequisite, and it is not in the ROADMAP row.
+//      MGPipeApplyAccess deliberately does not stamp the poison generations
+//      (PipeInputs.h:612-618): "a stamp says the filler published this for THIS verb, which is
+//      the walk's statement, not the applier's". Under split the filler is in another role, so
+//      NOTHING stamps, every FilledGen[] stays 0, MGPipeInputFieldIsFresh returns false for
+//      everything, and a pure server aborts on the FIRST read inside SyncRenderState with
+//      Fatal{UnmigratedPipeInput, "GetRenderStateParameters@<none>"} - before reaching any
+//      interesting case. So: the server stamps at the verb boundary. p1 defines what is
+//      stamped and for which verb; v1 places the call. Neither half works alone.
+//
+//   2. ACCEPTANCE. Four applier entry points return Bool - ResourceCreate, ResourceRespecify,
+//      ResourceSubData, SetTextureParams - and MapPersistent returns void*. Those returns are
+//      what the CLIENT gates destructive state changes on (clearing per-level dirty flags,
+//      latching parameters, adopting a pointer). They go back through the reply slot, id =
+//      record seq (R-3), and are collected in the barrier's existing wait (R-5). The client
+//      may not recompute any of them.
+//
+//   3. R-11, THE BORROWED-POINTER RULE. A SEG_STAGE run is valid from publish until retiredSeq
+//      passes the record naming it. NO APPLIER ENTRY POINT MAY HOLD A POINTER PAST ITS RETURN.
+//      The tree has exactly one violation and it is named: GLESBufferResource::hostBytes
+//      (Managers.h:839), written by Ops_H_SubData (Managers.cpp:1980-1983) and Ops_H_FlushRange
+//      (:2035), read by six later drains (:2000, :2062, :2080, :2111, :2741, :2843). Under split
+//      those two must copy into server-owned storage. MOBILEGL_IPC_AUDIT=1's 0xDD fill (R-2.5)
+//      is the mechanical control that says whether they did.
+
+#pragma once
+#include <Includes.h>
+
+#include <MG_Pipe/MGPipe.h>
+
+#include "../Transport/Ring.h"
+#include "../Wire/PipeWireCodec.h"
+
+namespace MobileGL::MG_Remote::Server {
+
+    // Writes answers into SEG_REPLY at seq % slots, stamping the seq back into the slot header
+    // so a wrong-slot read is detectable rather than plausible (table 0's slot header row:
+    // {Uint64 Seq; Int32 Status; Uint32 Size;}).
+    class ReplyPool final : public Wire::ReplySink {
+    public:
+        ReplyPool() = default;
+        ReplyPool(void* base, Uint64 sizeBytes, Uint32 slotCount, Uint32 slotBytes);
+
+        void PostReply(Uint64 seq, Int32 status, const void* bytes, Uint64 size) override;
+
+        // A reply larger than one slot is Fatal rather than chunked: P5's only large answer is
+        // ReadPixels, whose size the client already knows before it emits, so the slot size is
+        // chosen from that and an overflow means the two sides disagree about the frame.
+        Uint32 SlotBytes() const;
+
+    private:
+        Uint8* m_base = nullptr;
+        Uint64 m_size = 0;
+        Uint32 m_slots = 0;
+        Uint32 m_slotBytes = 0;
+    };
+
+    class PipeApplier {
+    public:
+        PipeApplier() = default;
+        PipeApplier(Wire::SegmentTable* segments, ReplyPool* replies);
+
+        // Decode one record, stamp the verb, apply, post the reply if the call has one, then
+        // advance appliedSeq by exactly one. P5 FORBIDS BATCHING appliedSeq (R-9): the barrier's
+        // waiter reads it, and a batched watermark promises work that has not run.
+        Bool ApplyOne(const Transport::RingRecordView& record);
+
+        // p1's rule, v1's call site. Called at the verb boundary, before the record's applier
+        // runs, with the verb the record belongs to.
+        void StampVerbBoundary(MG_Pipe::MGPWireOp op);
+
+        // R-7.2's counter, read by the gate. A BARRIER-PULLED field read on the server side
+        // increments PipeStats::CallClass::ResidualPulls (short name `rsp`); its value at the
+        // end of P5 IS the size of the P6/P7/P8 debt and goes into MEASUREMENTS.
+        Uint64 ResidualPullCount() const;
+
+        // R-11's audit: after a record retires, fill the SEG_STAGE bytes it referenced with
+        // 0xDD. Only under MOBILEGL_IPC_AUDIT=1, because it costs a write of every staged byte.
+        void PoisonRetiredStageBytes(Uint64 offset, Uint64 size);
+
+    private:
+        Wire::SegmentTable* m_segments = nullptr;
+        ReplyPool* m_replies = nullptr;
+        Wire::PipeWireDecoder m_decoder;
+        Uint64 m_residualPulls = 0;
+    };
+
+} // namespace MobileGL::MG_Remote::Server

MobileGL/MG_Remote/Server/ServerLoop.cpp

@@ -0,0 +1,49 @@
+// MobileGL - MobileGL/MG_Remote/Server/ServerLoop.cpp
+// Copyright (c) 2025-2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+
+// P5 c0 stubs for package v1 - the phase's highest-risk package.
+
+#include "ServerLoop.h"
+
+#include <MG_Util/Debug/Log.h>
+
+#include <cstdlib>
+
+namespace MobileGL::MG_Remote::Server {
+
+#define MGP5_C0_STUB(what)                                                                                             \
+    do {                                                                                                               \
+        MGLOG_F("MGPipe: Fatal{UnimplementedServerLoop, \"%s\"} - P5 package v1 has not landed "                       \
+                "this yet; c0 shipped the signature only",                                                             \
+                what);                                                                                                 \
+        std::abort();                                                                                                  \
+    } while (0)
+
+    MobileGLResult ServerLoop::Start(ServerSession&) { MGP5_C0_STUB("ServerLoop::Start"); }
+
+    void ServerLoop::Stop() { MGP5_C0_STUB("ServerLoop::Stop"); }
+
+    // Not a stub: teardown asks this to decide whether to Kill and join at all, and a teardown
+    // helper that aborts when the thread was never started is a hang in the shutdown path.
+    Bool ServerLoop::Running() const { return m_running; }
+
+    MG_Backend::BackendObject* ServerLoop::Backend() { MGP5_C0_STUB("ServerLoop::Backend"); }
+
+    MobileGLResult ServerLoop::RunOnApplyThread(ControlWork, void*) {
+        MGP5_C0_STUB("ServerLoop::RunOnApplyThread");
+    }
+
+    ServerLoop& ServerLoopInstance() {
+        // ID-8: leak at exit, like every MG_Remote singleton.
+        static ServerLoop& instance = *new ServerLoop{};
+        return instance;
+    }
+
+#undef MGP5_C0_STUB
+
+} // namespace MobileGL::MG_Remote::Server

MobileGL/MG_Remote/Server/ServerLoop.h

@@ -0,0 +1,91 @@
+// MobileGL - MobileGL/MG_Remote/Server/ServerLoop.h
+// Copyright (c) 2025-2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+
+// The apply thread and the server's private backend object. Owner: package v1 - the highest
+// risk item in P5. Signatures by c0.
+//
+// WHY THE THREAD IS THE POINT. DirectGLES has 16 IsBackendContextCurrentOnThisThread() guards
+// (DirectGLES.cpp:12034..12428) and Managers.cpp has 16 CanTouchGLNow() guards (:1494..:3428);
+// every one of them DEGRADES when the answer is false - fences become always-signaled, queries
+// return null handles, Present creates no frame fence so the buffer pool's recycle watermark
+// never advances, and the two persistent-map acquisitions (Managers.cpp:1494, :2170) DECLINE,
+// which would make PersistentCoherentMapScenario unreachable. Making the apply thread the
+// context owner for life turns all 32 of those answers true on the server and removes the
+// whole degradation class at once. It is also exactly the shape P6's spawned server inherits.
+//
+// P5 BUILDS ONE THREAD, NOT TWO. No mgl-srv-io: inproc's control plane is in the same process.
+// P6 splits it.
+//
+// PARKING AND SHUTDOWN. The thread parks on Doorbell::Wait(consumerParked, ready, spinUs,
+// kWaitForever) and shuts down when Wait returns false with Dead() set. Doorbell::Kill()
+// (Doorbell.h:211-221) IS THE ONLY THING that wakes a thread parked on kWaitForever - a fact
+// ARCHITECTURE.md's teardown order (:537) omits and InProcessTransportTest.cpp:344 already
+// pins. Kill BEFORE join; join before the client frees any emitter-owned Vector; and the join
+// must be bounded (that test uses 5 s) so a regression is a red test and not a hung CI job.
+//
+// THE EGL OWNERSHIP MOVE. eglMakeCurrent runs ONCE on this thread and is never released
+// (DirectGLES.cpp:11925 plus the six cache invalidations at :11933-11953, which become a
+// one-time startup cost instead of a per-make-current storm). The client's nine EGL virtuals
+// become BLOCKING control requests executed here. ReleaseEGLResources and
+// ~BackendObject_DirectGLES MUST be blocking: MobileGL::Destroy() (MobileGL/Init.cpp:68)
+// otherwise walks on while the server still holds the context.
+//
+// THE FALLBACK IS PRE-DECLARED, NOT INVENTED UNDER PRESSURE (R-1). If the context migration is
+// still not running ClearThenReadPixels at the end of v1's fourth working day, the integrator -
+// not the package - declares `inproc-inline`: the client thread drains the ring itself, no
+// thread is created, no context migrates, and a second package picks up the thread arm.
+
+#pragma once
+#include <Includes.h>
+
+#include "ServerSession.h"
+
+namespace MobileGL::MG_Remote::Server {
+
+    class ServerLoop {
+    public:
+        // Creates the apply thread, names it mgl-srv-apply, applies
+        // MOBILEGL_IPC_SERVER_AFFINITY (borrowing ShaderCompilePool's big-core detection) and
+        // LOGS THE RESOLVED MASK - an affinity that silently did nothing is indistinguishable
+        // from one that worked, and the split's whole performance claim rests on both halves
+        // landing on fast cores.
+        MobileGLResult Start(ServerSession& session);
+
+        // Kill the doorbell, join the thread (bounded), then destroy the private backend object
+        // ON THAT THREAD before it exits. Blocking by contract - see the header note.
+        void Stop();
+
+        Bool Running() const;
+
+        // The server role's own backend object. NOT pActiveBackendObject: that global holds the
+        // client's BackendObject_Remote. Table 3's ruling is that the server holds its
+        // BackendObject_DirectGLES privately here, and that the seven backend-internal reads of
+        // pActiveBackendObject - ClampSamplesToBackendSupport (BackendObject_DirectGLES.cpp:815,
+        // :819) and five in Utils.cpp (:74, :82, :126, :220, :260), all of them format-capability
+        // lookups - take the format cache as a parameter instead. That is six functions across
+        // two files, and it is why no thread-keyed shim is needed for MOBILEGL_BUILD_DISAGGREGATED_INPROC.
+        MG_Backend::BackendObject* Backend();
+
+        // Run one blocking control request on the apply thread and wait for it. This is how all
+        // nine EGL lifecycle virtuals cross; it is deliberately NOT a queue of async messages,
+        // because every one of them has a return value the caller acts on immediately.
+        //
+        // A raw function pointer plus a user pointer, not std::function: this runs on the
+        // teardown path too, and the teardown path may not allocate - ID-8's leak-at-exit rule
+        // exists because frontend destructors reach here from exit handlers.
+        using ControlWork = MobileGLResult (*)(void* user);
+        MobileGLResult RunOnApplyThread(ControlWork work, void* user);
+
+    private:
+        ServerSession* m_session = nullptr;
+        Bool m_running = false;
+    };
+
+    ServerLoop& ServerLoopInstance();
+
+} // namespace MobileGL::MG_Remote::Server

MobileGL/MG_Remote/Server/ServerSession.cpp

@@ -0,0 +1,50 @@
+// MobileGL - MobileGL/MG_Remote/Server/ServerSession.cpp
+// Copyright (c) 2025-2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+
+// P5 c0 stubs for package s1.
+
+#include "ServerSession.h"
+
+#include <MG_Util/Debug/Log.h>
+
+#include <cstdlib>
+
+namespace MobileGL::MG_Remote::Server {
+
+#define MGP5_C0_STUB(what)                                                                                             \
+    do {                                                                                                               \
+        MGLOG_F("MGPipe: Fatal{UnimplementedServerSession, \"%s\"} - P5 package s1 has not landed "                    \
+                "this yet; c0 shipped the signature only",                                                             \
+                what);                                                                                                 \
+        std::abort();                                                                                                  \
+    } while (0)
+
+    ServerSession* ServerSession::Active() { return nullptr; }
+
+    MobileGLResult ServerSession::Accept(Transport::ITransport&) { MGP5_C0_STUB("ServerSession::Accept"); }
+
+    MobileGLResult ServerSession::PublishCapsSnapshot() {
+        MGP5_C0_STUB("ServerSession::PublishCapsSnapshot");
+    }
+
+    Transport::RingConsumer& ServerSession::CommandRing() { return m_commands; }
+    Transport::RingControl& ServerSession::Control() { MGP5_C0_STUB("ServerSession::Control"); }
+    Wire::SegmentTable& ServerSession::Segments() { return m_segments; }
+    PipeApplier& ServerSession::Applier() { return m_applier; }
+    ReplyPool& ServerSession::Replies() { return m_replies; }
+
+    Transport::Doorbell& ServerSession::ConsumerDoorbell() {
+        MGP5_C0_STUB("ServerSession::ConsumerDoorbell");
+    }
+    Transport::Doorbell& ServerSession::ProducerDoorbell() {
+        MGP5_C0_STUB("ServerSession::ProducerDoorbell");
+    }
+
+#undef MGP5_C0_STUB
+
+} // namespace MobileGL::MG_Remote::Server

MobileGL/MG_Remote/Server/ServerSession.h

@@ -0,0 +1,72 @@
+// MobileGL - MobileGL/MG_Remote/Server/ServerSession.h
+// Copyright (c) 2025-2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+
+// The server half of a session: the consumer side of the rings, the handshake reply, the caps
+// snapshot. Owner: package s1. Signatures by c0.
+//
+// The four segment sizes are already pinned by ProtocolSmokeTest.cpp:72 and are not up for
+// re-derivation here: SEG_CMD 8 MiB, SEG_STAGE 32 MiB, SEG_REPLY 8 MiB, SEG_EVENT 256 KiB.
+// MOBILEGL_IPC_RING_MB and MOBILEGL_IPC_STAGE_MB move the first two; the ring caps ONE record
+// at half its size, so the default 8 MiB caps a record at 4 MiB (R-10).
+//
+// THE TWO DOORBELL ACCESSORS ARE ON THE CONCRETE CLASS, NOT ON ITransport
+// (InProcessTransport.h:64-68). P5 decides this now rather than letting P6 discover it: the
+// SESSION owns the pair and hands out references, so ITransport stays the dumb control-plane
+// interface its header says it is and SocketTransport does not have to grow two accessors it
+// has no natural home for. Discovering this in P6 would mean re-laying one package's call sites.
+
+#pragma once
+#include <Includes.h>
+
+#include <MG_Pipe/MGPipe.h>
+
+#include "../Transport/Doorbell.h"
+#include "../Transport/ITransport.h"
+#include "../Transport/Ring.h"
+#include "../Wire/PipeWireCodec.h"
+#include "PipeApplier.h"
+
+namespace MobileGL::MG_Remote::Server {
+
+    class ServerSession {
+    public:
+        static ServerSession* Active();
+
+        // Maps the four segments, answers Hello with Welcome, and publishes the first
+        // CapsSnapshot. The ABI assertion (CapsCodec.h) happens HERE, before a single record is
+        // decoded: sizeof(DynamicBackendParameters), sizeof(MGPCaps), sizeof(GLFunctionsTable)
+        // and the build fingerprint must match, and a mismatch is Fatal{AbiMismatch}.
+        MobileGLResult Accept(Transport::ITransport& transport);
+
+        // Re-publishes the whole snapshot. R-12: a SECOND arrival IS the invalidation signal,
+        // which is how DirectGLES - which has no OnCapsInvalidated producer - tells the client
+        // its InitCapabilities re-ran, without any dev-shaped backend edit. It is also the
+        // re-open signal for "the server's ES context died and its rings were dropped", the
+        // event MGPipeCallbacks has no eleventh slot for (MGPipeCallbacks.h:56-58).
+        MobileGLResult PublishCapsSnapshot();
+
+        Transport::RingConsumer& CommandRing();
+        Transport::RingControl& Control();
+        Wire::SegmentTable& Segments();
+        PipeApplier& Applier();
+        ReplyPool& Replies();
+
+        // The client rings this one; the apply thread parks on it.
+        Transport::Doorbell& ConsumerDoorbell();
+        // The server rings this one, but only when producerParked is set (a store to a shared
+        // cache line otherwise burns a big core for a whole frame on a phone).
+        Transport::Doorbell& ProducerDoorbell();
+
+    private:
+        Transport::RingConsumer m_commands;
+        Wire::SegmentTable m_segments;
+        PipeApplier m_applier;
+        ReplyPool m_replies;
+    };
+
+} // namespace MobileGL::MG_Remote::Server

MobileGL/MG_Remote/Transport/Ring.h

@@ -41,6 +41,49 @@
 // (Records.def / PipeCalls.def) is a separate deliverable; the ring itself
 // only needs kind/flags/size, so it can carry the real records the day they
 // land without changing shape.
+//
+// ---------------------------------------------------------------------------
+// THE FIVE WATERMARKS (P5 R-9). One sentence each, and they are a contract:
+// every one of the five was declared here at P0 and written by nobody but
+// InitRingControl, so until P5 there was nothing to disagree with.
+//
+//   submittedSeq        Advanced by the PRODUCER after it publishes. NOBODY
+//                       WAITS ON IT - it is diagnostic, the answer to "how far
+//                       ahead of the server is the client right now".
+//   appliedSeq          Advanced by the CONSUMER for EVERY SINGLE RECORD it
+//                       applies. The client's verb barrier and every reply wait
+//                       read it, so it is the one watermark P5 FORBIDS BATCHING:
+//                       the sixty-four-record batching this ring was designed
+//                       for makes a waiter block on work that already ran, or -
+//                       far worse - resume on work that has not.
+//   retiredSeq          Advanced by the CONSUMER once it has finished with the
+//                       SEG_STAGE bytes a record referenced. The staging
+//                       allocator reclaims behind it, and nothing else may.
+//   completedFrameSerial Advanced by the SERVER when a present completes. What
+//                       recycling and ageing wait on; it trails appliedSeq by
+//                       the GPU's own depth and must never be conflated with it.
+//   presentAckSerial    Advanced by the SERVER when it returns a present credit.
+//                       The client's present throttle waits on it; it is the
+//                       only back-pressure that bounds latency rather than bytes.
+//
+// Every wait on all five is `>=`, never `==`: a waiter that tests equality
+// misses the wakeup the moment a producer or consumer moves by more than one.
+//
+// BATCHING MAY ONLY MAKE A WATERMARK LATE. All five except appliedSeq may be
+// published lazily, because a waiter that sees an old value waits longer than
+// it had to and is still correct. NONE of them may ever be published EARLY: a
+// watermark that reports more than was actually done turns every waiter into a
+// silent use of work that has not happened, and there is no checksum anywhere
+// on this ring that would catch it.
+//
+// kRecPad DOES NOT ADVANCE SEQ. A wrap filler is framing, not a record: it has
+// no opcode, no payload meaning and no reply slot. Both sides must skip it
+// BEFORE counting. If one side counts it and the other does not, the two seq
+// spaces drift by one at every wrap - and because seq IS the reply-slot id
+// (P5 R-3), a drifted seq silently reads another call's answer rather than
+// failing. Nothing on this ring would detect that, which is why the rule is
+// stated here rather than left to each side's loop.
+// ---------------------------------------------------------------------------
 
 #pragma once
 

MobileGL/MG_Remote/Wire/PipeWireCodec.cpp

@@ -0,0 +1,116 @@
+// MobileGL - MobileGL/MG_Remote/Wire/PipeWireCodec.cpp
+// Copyright (c) 2025-2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+
+// P5 c0's stubs for package w1. Every body is MGLOG_F + std::abort and NOT a silent no-op:
+// an unimplemented codec that returns quietly is exactly how a split lane runs monolith and
+// goes green, which is the failure the whole phase is built to make impossible.
+
+#include "PipeWireCodec.h"
+
+#include <MG_Remote/Protocol/generated/protocol_generated.h>
+#include <MG_Util/Debug/Log.h>
+
+#include <cstdlib>
+
+namespace MobileGL::MG_Remote::Wire {
+
+    // Table 0's first row, mechanised: this enum and the schema's SegmentKind are ONE id
+    // space, and the only place they are compared is here. A schema edit that renumbers a
+    // segment is a build break rather than a wrong pointer on a ring.
+    //
+    // Fully qualified from the global namespace on purpose: the generated header's namespace
+    // is `MobileGL::Wire` and we are inside `MobileGL::MG_Remote::Wire`, so a bare `Wire::`
+    // resolves to THIS namespace and the assertion would silently be about the wrong enum -
+    // or, as it first was, fail to compile for a reason that looks unrelated.
+    static_assert(static_cast<Uint32>(::MobileGL::Wire::SegmentKind::None) == kSegNone);
+    static_assert(static_cast<Uint32>(::MobileGL::Wire::SegmentKind::Cmd) == kSegCmd);
+    static_assert(static_cast<Uint32>(::MobileGL::Wire::SegmentKind::Stage) == kSegStage);
+    static_assert(static_cast<Uint32>(::MobileGL::Wire::SegmentKind::Reply) == kSegReply);
+    static_assert(static_cast<Uint32>(::MobileGL::Wire::SegmentKind::Event) == kSegEvent);
+    static_assert(static_cast<Uint32>(::MobileGL::Wire::SegmentKind::Shadow) == kSegShadow);
+    static_assert(static_cast<Uint32>(::MobileGL::Wire::SegmentKind::Adopt) == kSegAdopt);
+    // And the other half of table 0's rule: MG_Pipe's "no segment" sentinel is the same 0.
+    static_assert(static_cast<Uint32>(MG_Pipe::kMGHostSpanSegNone) == kSegNone,
+                  "kMGHostSpanSegNone and SegmentId::kSegNone must be the same value");
+
+#define MGP5_C0_STUB(what)                                                                                             \
+    do {                                                                                                               \
+        MGLOG_F("MGPipe: Fatal{UnimplementedWireCodec, \"%s\"} - P5 package w1 has not landed "                        \
+                "this yet; c0 shipped the signature only",                                                             \
+                what);                                                                                                 \
+        std::abort();                                                                                                  \
+    } while (0)
+
+    void SegmentTable::Install(SegmentId, SegmentView) { MGP5_C0_STUB("SegmentTable::Install"); }
+
+    SegmentView SegmentTable::Get(SegmentId) const { MGP5_C0_STUB("SegmentTable::Get"); }
+
+    const void* SegmentTable::Resolve(Uint32, Uint64, Uint64) const {
+        MGP5_C0_STUB("SegmentTable::Resolve");
+    }
+
+    void SegmentTable::InstallProcessResolver() { MGP5_C0_STUB("SegmentTable::InstallProcessResolver"); }
+
+    void SegmentTable::UninstallProcessResolver() {
+        MGP5_C0_STUB("SegmentTable::UninstallProcessResolver");
+    }
+
+    // NOT a stub: the two Fatal helpers are the one thing every package needs on day one, and
+    // a Fatal that is itself unimplemented would report the wrong failure.
+    void WireProtocolFatal(const char* what, const char* detail) {
+        MGLOG_F("MGPipe: Fatal{ProtocolCorruption, \"%s\"} %s", what, detail != nullptr ? detail : "");
+        std::abort();
+    }
+
+    void WireProtocolFatalAt(const char* what, Uint64 got, Uint64 expected) {
+        MGLOG_F("MGPipe: Fatal{ProtocolCorruption, \"%s\"} got=%llu expected=%llu", what,
+                static_cast<unsigned long long>(got), static_cast<unsigned long long>(expected));
+        std::abort();
+    }
+
+    void CheckBlobIsHonest(MG_Pipe::MGPWireOp, const MG_Pipe::MGPBlobRef&, const SegmentTable&) {
+        MGP5_C0_STUB("CheckBlobIsHonest");
+    }
+
+    void CheckHostSpanIsHonest(const MG_Pipe::MGHostSpan&) { MGP5_C0_STUB("CheckHostSpanIsHonest"); }
+
+    PipeWireEncoder::PipeWireEncoder(Transport::RingControl* control, Transport::RingProducer* cmd,
+                                     Transport::RingProducer* stage, SegmentTable* segments)
+        : m_control(control), m_cmd(cmd), m_stage(stage), m_segments(segments) {}
+
+    Bool PipeWireEncoder::Valid() const { return m_control != nullptr && m_cmd != nullptr; }
+
+    MG_Pipe::MGPBlobRef PipeWireEncoder::StageBytes(const void*, Uint64) {
+        MGP5_C0_STUB("PipeWireEncoder::StageBytes");
+    }
+
+    Uint64 PipeWireEncoder::EncodeRecord(MG_Pipe::MGPWireOp, const void*, Uint64, const void*, Uint64) {
+        MGP5_C0_STUB("PipeWireEncoder::EncodeRecord");
+    }
+
+    void PipeWireEncoder::Publish() { MGP5_C0_STUB("PipeWireEncoder::Publish"); }
+
+    Uint64 PipeWireEncoder::EmitSeq() const { return m_emitSeq; }
+
+    Uint64 PipeWireEncoder::MaxRecordBytesSeen() const { return m_maxRecordBytes; }
+
+    PipeWireDecoder::PipeWireDecoder(Transport::RingControl* control, SegmentTable* segments,
+                                     ReplySink* replies)
+        : m_control(control), m_segments(segments), m_replies(replies) {}
+
+    Bool PipeWireDecoder::Valid() const { return m_control != nullptr && m_segments != nullptr; }
+
+    Bool PipeWireDecoder::DecodeAndApply(const Transport::RingRecordView&) {
+        MGP5_C0_STUB("PipeWireDecoder::DecodeAndApply");
+    }
+
+    Uint64 PipeWireDecoder::AppliedSeq() const { return m_applySeq; }
+
+#undef MGP5_C0_STUB
+
+} // namespace MobileGL::MG_Remote::Wire

MobileGL/MG_Remote/Wire/PipeWireCodec.h

@@ -0,0 +1,230 @@
+// MobileGL - MobileGL/MG_Remote/Wire/PipeWireCodec.h
+// Copyright (c) 2025-2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+
+// G3: the MGPipe record codec. Owner: package w1.
+//
+// This header is the CONTRACT (MG_Remote/CONTRACT-P5.md) in C++ form; P5's c0 package wrote
+// it so the other seven could compile on day one against signatures that cannot then move
+// under them. Every body below is a named Fatal until w1 lands the real one.
+//
+// WHAT THIS LAYER IS, AND WHAT IT IS NOT
+//
+// It turns one MGPipe call into bytes in SEG_CMD (+ SEG_STAGE), and bytes back into ONE CALL
+// OF AN EXISTING MGPipeApply* FREE FUNCTION. It owns NO semantics: MG_Pipe/PipeApply.cpp is
+// not edited by this package, and a decoder arm that "handles" a record itself rather than
+// delegating is a review failure (R-4's rule, one level down).
+//
+// THE FIVE HONESTY RULES (R-2), because they are what make `inproc` worth running at all.
+// In the same address space every shortcut works: MGHostSpan::Ptr dereferences, a blobref
+// whose Offset is a host address resolves, and MGPipeApplyMapPersistent's return value is a
+// usable pointer. So the codec is held to the SPAWN rules even when it does not need to be:
+//   1. encoder writes MGHostSpan::Ptr == nullptr and points Seg/Offset at SEG_STAGE;
+//   2. encoder fills a real Seg, a real in-segment Offset and a NON-ZERO Size for every
+//      MGPBlobRef that carries content;
+//   3. decoder Fatal{ProtocolCorruption} on: Ptr != nullptr; a content record with
+//      Blob.Size == 0; Size != 0 with Seg == kSegNone; Offset + Size past the segment;
+//   4. MGPipeApplyMapPersistent returns nullptr under split (R-6; b1's half);
+//   5. with MOBILEGL_IPC_AUDIT=1 the server fills a retired record's SEG_STAGE bytes with
+//      0xDD, so an implementation that kept a pointer past apply reads 0xDD next frame.
+//
+// SEQ. The record ordinal IS the sequence number and IS the reply-slot id (R-3): there is no
+// per-record seq field on the wire (ARCHITECTURE.md:124) and no second id space. Seq is
+// 1-based so that 0 can mean "nothing encoded". A kRecPad wrap filler DOES NOT ADVANCE SEQ -
+// both sides must skip it before counting, or every ring wrap offsets the two sides'
+// numbering permanently and nothing checksums it (R-9, Ring.h's header).
+
+#pragma once
+#include <Includes.h>
+
+#include <MG_Pipe/MGPipe.h>
+
+#include "../Transport/Ring.h"
+
+namespace MobileGL::MG_Remote::Wire {
+
+    // ---- table 0: the segment id space -------------------------------------------------
+    //
+    // The SAME VALUES as Protocol::SegmentKind (protocol.fbs:36-44); PipeWireCodec.cpp
+    // static_asserts the two agree, which is the only place the flatbuffers header and this
+    // enum meet. 0 is ALWAYS "no segment" and is never a real segment id, which is what lets
+    // MGPBlobRef{Seg == 0, Size != 0} be a detectable fault rather than a legal shape.
+    enum SegmentId : Uint32 {
+        kSegNone = 0,
+        kSegCmd = 1,    // client-owned command ring (RingControl + records)
+        kSegStage = 2,  // client-owned bulk staging: every blob and every var-tail's bytes
+        kSegReply = 3,  // server-owned reply pool, addressed seq % slots (R-3)
+        kSegEvent = 4,  // server-owned event ring (the reverse channel)
+        kSegShadow = 5, // client-owned per-object shadow (P8+)
+        kSegAdopt = 6,  // server-owned adopted store, client RW (P11)
+    };
+
+    // Seq is 1-based. 0 is "no record", never a valid reply-slot id.
+    inline constexpr Uint64 kInvalidSeq = 0;
+
+    // One mapped segment as this ROLE sees it. Two roles in one process have two different
+    // SegmentTables over the same memory on purpose: a client that can resolve SEG_REPLY as
+    // if it owned it is the inproc cheat R-2 exists to kill.
+    struct SegmentView {
+        void* Base = nullptr;
+        Uint64 Size = 0;
+    };
+
+    // ---- the per-role segment table, and the process resolver hook ---------------------
+    //
+    // gMGPipeSegmentResolver (MG_Pipe/MGPipeHostSpan.h:47) is a plain non-atomic inline
+    // variable and there is exactly ONE of it per process, so under inproc the two roles
+    // cannot both install their own into it. TABLE 3's ruling: the resolver is installed by
+    // the SERVER role only, before the apply thread starts, and the client never resolves a
+    // span at all (it only ever writes Ptr = nullptr). Install() therefore takes the role.
+    class SegmentTable {
+    public:
+        void Install(SegmentId seg, SegmentView view);
+        SegmentView Get(SegmentId seg) const;
+
+        // Bounds-checked resolve. Returns nullptr when seg is unknown, size is 0, or
+        // offset + size runs past the segment; the CALLER escalates that to
+        // Fatal{ProtocolCorruption} (R-2.3) rather than this returning into a Fatal, so a
+        // unit test can exercise the arithmetic without dying.
+        const void* Resolve(Uint32 seg, Uint64 offset, Uint64 size) const;
+
+        // Points MG_Pipe::gMGPipeSegmentResolver at this table. Server role only; asserts if
+        // a resolver is already installed, because two roles racing on one inline variable is
+        // the failure this function exists to make loud.
+        void InstallProcessResolver();
+        static void UninstallProcessResolver();
+
+    private:
+        SegmentView m_views[kSegAdopt + 1];
+    };
+
+    // ---- the four Fatal arms, worded once ----------------------------------------------
+    //
+    // One function so encoder, decoder and every package's own bounds check produce the SAME
+    // log line. `what` is the record or field; `detail` is the number that was wrong.
+    [[noreturn]] void WireProtocolFatal(const char* what, const char* detail);
+    [[noreturn]] void WireProtocolFatalAt(const char* what, Uint64 got, Uint64 expected);
+
+    // R-2.3 arms 1-4 over one record's blobref. Split only; a monolith emission is exempt by
+    // construction because it never reaches this layer.
+    void CheckBlobIsHonest(MG_Pipe::MGPWireOp op, const MG_Pipe::MGPBlobRef& blob,
+                           const SegmentTable& segments);
+    // R-2.3 arm for MGHostSpan. P5's reduced path should produce ZERO host spans
+    // (kCapNeedsHostIndexBytes / kCapNeedsHostUboBytes are both 0 in P5, table 0), so this
+    // firing at all is a finding, not just a corruption check.
+    void CheckHostSpanIsHonest(const MG_Pipe::MGHostSpan& span);
+
+    // ---- encoder -----------------------------------------------------------------------
+    //
+    // Not thread safe: one encoder per client context, driven by the GL thread, by
+    // construction (SPSC is the ring's contract too).
+    class PipeWireEncoder {
+    public:
+        PipeWireEncoder() = default;
+        PipeWireEncoder(Transport::RingControl* control, Transport::RingProducer* cmd,
+                        Transport::RingProducer* stage, SegmentTable* segments);
+
+        Bool Valid() const;
+
+        // Copies `size` bytes into SEG_STAGE and returns the blobref that names them:
+        // {Seg = kSegStage, Offset = in-segment byte offset, Size = size}. R-2.2 - Size is
+        // NEVER 0 for a content blob, and a 0-size call is a programming error that Fatals
+        // rather than returning an empty ref, because "the record declared no blob" and "the
+        // record declared an empty blob" must not be spelled the same way on a wire.
+        //
+        // The bytes are valid until retiredSeq passes the record that names them (R-11).
+        MG_Pipe::MGPBlobRef StageBytes(const void* bytes, Uint64 size);
+
+        // Writes one record: header (op, MGPipeCallFlagsFor(op), total size), then the fixed
+        // payload, then the variable tail. Returns the record's SEQ, which is also its
+        // reply-slot id (R-3), or kInvalidSeq if the ring refused it.
+        //
+        // A record larger than RingProducer::MaxRecordBytes() is Fatal{RingOverrun}, NOT a
+        // wait: R-10 says P5 does no chunking and must instead PROVE it never needs any, so
+        // this is where the proof fails loudly if it is wrong. MaxRecordBytesSeen() is the
+        // counter that feeds that proof into MEASUREMENTS.
+        Uint64 EncodeRecord(MG_Pipe::MGPWireOp op, const void* payload, Uint64 payloadBytes,
+                            const void* varTail = nullptr, Uint64 varTailBytes = 0);
+
+        // Release-stores the head cursor, then rings the consumer doorbell IF PARKED. The
+        // order is pinned by RingTest.cpp:446 and must not be swapped: notify-then-publish
+        // loses the wakeup.
+        void Publish();
+
+        // The highest seq this encoder has produced. The verb barrier (R-1) waits for
+        // RingControl::appliedSeq to reach it.
+        Uint64 EmitSeq() const;
+
+        // R-10's proof obligation: the largest single record this encoder has written.
+        Uint64 MaxRecordBytesSeen() const;
+
+    private:
+        Transport::RingControl* m_control = nullptr;
+        Transport::RingProducer* m_cmd = nullptr;
+        Transport::RingProducer* m_stage = nullptr;
+        SegmentTable* m_segments = nullptr;
+        Uint64 m_emitSeq = kInvalidSeq;
+        Uint64 m_maxRecordBytes = 0;
+    };
+
+    // ---- decoder -----------------------------------------------------------------------
+
+    // Where a kReplySlot answer goes. Declared HERE and not in Server/ so the codec does not
+    // depend on the server session: the decoder's job ends at "produce the answer bytes".
+    //
+    // The slot is addressed seq % slots and the server writes the seq back into the slot
+    // header for self-check (table 0's slot header row). Status: 0 = OK, 1 = DECLINED,
+    // 2 = ERROR. DECLINED IS A REAL ANSWER, not a failure - it is how MapPersistent says
+    // nullptr (R-6) and how the four Bool acceptance entry points say false (R-5).
+    class ReplySink {
+    public:
+        virtual ~ReplySink() = default;
+        static constexpr Int32 kStatusOk = 0;
+        static constexpr Int32 kStatusDeclined = 1;
+        static constexpr Int32 kStatusError = 2;
+        virtual void PostReply(Uint64 seq, Int32 status, const void* bytes, Uint64 size) = 0;
+    };
+
+    // Not thread safe: one decoder on the apply thread, by construction.
+    class PipeWireDecoder {
+    public:
+        PipeWireDecoder() = default;
+        PipeWireDecoder(Transport::RingControl* control, SegmentTable* segments,
+                        ReplySink* replies);
+
+        Bool Valid() const;
+
+        // Decodes ONE record and calls the matching MGPipeApply* free function.
+        //
+        // TWO BOUNDS CHECKS, NOT ONE. The generated MGP_WIRE_CHECK_BOUNDS only proves
+        // `size >= sizeof(MGPWireRec_X)` - IT CANNOT SEE THE TAIL, so a record declaring
+        // Count = 4000 while carrying 8 bytes passes it today. The decoder must recompute the
+        // total from the declared count(s) and require it to EQUAL MGPWireRecHeader::Size.
+        // The three double-tailed shapes are SetShaderBuffers (MGPBufferRange[Count] then
+        // MGHostSpan[HostSpanCount]), SetStreamOutputTargets (MGPBufferRange[Count] then
+        // Uint32[Count]) and DrawVbo (MGPDrawRange[NumDraws] then a conditional MGHostSpan).
+        //
+        // Returns whether the record was applied. False is reserved for a record this build
+        // deliberately does not implement; a MALFORMED record never returns, it Fatals.
+        //
+        // A kRecPad record must be skipped by the CALLER before this is reached; passing one
+        // here Fatals, because a pad that reached the decoder has already been counted.
+        Bool DecodeAndApply(const Transport::RingRecordView& record);
+
+        // Advanced by exactly one per applied non-pad record. P5 FORBIDS BATCHING IT (R-9):
+        // the verb barrier's waiter reads it, and a batched watermark makes the client wait
+        // for records the server has not run.
+        Uint64 AppliedSeq() const;
+
+    private:
+        Transport::RingControl* m_control = nullptr;
+        SegmentTable* m_segments = nullptr;
+        ReplySink* m_replies = nullptr;
+        Uint64 m_applySeq = kInvalidSeq;
+    };
+
+} // namespace MobileGL::MG_Remote::Wire

MobileGL/MG_State/GLState/FramebufferState/FramebufferObject.cpp

@@ -25,15 +25,22 @@ namespace MobileGL::MG_State::GLState {
 
 #if MOBILEGL_PIPE_PUSH
     FramebufferObject::~FramebufferObject() {
-        // P2 step e2: ANNOUNCE the death instead of leaving the backend to discover it in a
-        // garbage sweep. This is the last SharedPtr to this object dropping - not the
-        // glDelete* that only marks the name and leaves a still-bound object very much
-        // alive - so it is the exact moment the backend's twin, and the driver storage
-        // that twin owns, stop being reachable. The notice carries the lifetime id
-        // because the object no longer exists to be passed, and because the lifetime id
-        // is what the client slot allocator resolves the handle from. No-op unless a
-        // backend registered the ops (a pull build declares none at all).
-        NotifyStateObjectDestroyed(MG_Pipe::MGPipeKind::Framebuffer, m_lifetimeId);
+        // P4a D-I2: A FRAMEBUFFER HAS A HANDLE AND NO WIRE LIFETIME. PipeCalls.def carries
+        // resource_destroy and five delete_* rows and NO framebuffer delete, because a
+        // framebuffer is not a resource and is not a CSO - it is STATE, and
+        // set_framebuffer_state is the only call that names one - and the catalogue is closed,
+        // so P4a invents no row. The helper is therefore steps 2 and 3 only: the death notice,
+        // raised while the handle still resolves (this is the P2 step-e2 announcement that used
+        // to stand here alone - the last SharedPtr to this object dropping, not the glDelete*
+        // that only marks the name and leaves a still-bound object very much alive), and then
+        // the slot.
+        //
+        // What makes a dangling Fbo unreachable is the frontend's own
+        // MarkFramebufferObjectForDeletion path, which already rebinds any slot holding the
+        // victim to framebuffer 0; and a RECYCLED framebuffer handle can never be suppressed
+        // against its predecessor's record, because Fbo carries Gen and Gen is inside the
+        // record's ContentHash.
+        MG_Pipe::MGPipeEmitFramebufferDestroyAndFree(m_lifetimeId);
     }
 #endif
 

MobileGL/MG_State/GLState/ProgramState/ProgramArtifacts.h

@@ -408,6 +408,17 @@ namespace MobileGL::MG_State::GLState {
     // Free constrained templates rather than members so the struct bodies above stay a verbatim
     // move. The sizeof trip wires below are what keep these tables honest: a member added to a
     // struct changes its size, trips the assertion, and the message sends the author here.
+    //
+    // THE SERIALIZER NOW EXISTS (P4a): MG_State/GLState/ProgramState/ProgramArtifactsCodec.
+    // {h,cpp}, beside this header rather than inside it so the check_include_closure.py
+    // "artifacts-header" probe stays untouched. It is two visitors over the tables below - a
+    // writer that appends to a Vector<Uint8> and a reader that consumes one - length-prefixed,
+    // little-endian, with a format-version word first and a MGL_LINKARTIFACTS_SIZE echo
+    // second, so a struct that gained a field and a codec that did not is a mismatch at READ
+    // time rather than a silent truncation. Adding a member to any struct above therefore
+    // means: add its VisitFields row here, update the sizeof number below, and bump
+    // kProgramArtifactsCodecVersion. `LinkArtifacts::program` stays the one deliberate
+    // omission, and the codec has no arm for it.
     template <class Self, class V>
         requires std::same_as<std::remove_const_t<Self>, TypeFacts>
     void VisitFields(Self& a, V&& v) {
@@ -549,7 +560,7 @@ namespace MobileGL::MG_State::GLState {
     // ---- trip wires ----
     // TypeFacts is a POD on every ABI: 13 Bool + 3 bytes of padding + 7 x 4-byte scalars.
     static_assert(std::is_trivially_copyable_v<TypeFacts> && sizeof(TypeFacts) == 44,
-                  "TypeFacts changed: add the field to VisitFields(TypeFacts) (and its serializer when one exists), then update this number");
+                  "TypeFacts changed: add the field to VisitFields(TypeFacts) (and ProgramArtifactsCodec.cpp's serializer), then update this number");
     // The container-bearing structs have one size per standard library (std::string and
     // std::set differ between libstdc++ and libc++), so their numbers are pinned PER STL:
     // libstdc++ (the Linux CI toolchain) here, libc++ (the NDK) by the integrator, MSVC
@@ -565,12 +576,12 @@ namespace MobileGL::MG_State::GLState {
 #endif
 #ifdef MGL_LINKARTIFACTS_SIZE
     static_assert(sizeof(ResourceReflection) == MGL_RESOURCEREFLECTION_SIZE,
-                  "ResourceReflection changed size: add the field to VisitFields(ResourceReflection) (and its serializer when one exists), then update this number");
+                  "ResourceReflection changed size: add the field to VisitFields(ResourceReflection) (and ProgramArtifactsCodec.cpp's serializer), then update this number");
     static_assert(sizeof(XfbVarying) == MGL_XFBVARYING_SIZE,
-                  "XfbVarying changed size: add the field to VisitFields(XfbVarying) (and its serializer when one exists), then update this number");
+                  "XfbVarying changed size: add the field to VisitFields(XfbVarying) (and ProgramArtifactsCodec.cpp's serializer), then update this number");
     static_assert(sizeof(LinkArtifacts) == MGL_LINKARTIFACTS_SIZE,
-                  "LinkArtifacts changed size: add the field to VisitFields(LinkArtifacts) (and its serializer when one exists), then update this number");
+                  "LinkArtifacts changed size: add the field to VisitFields(LinkArtifacts) (and ProgramArtifactsCodec.cpp's serializer), then update this number");
     static_assert(sizeof(SpirvArtifacts) == MGL_SPIRVARTIFACTS_SIZE,
-                  "SpirvArtifacts changed size: add the field to VisitFields(SpirvArtifacts) (and its serializer when one exists), then update this number");
+                  "SpirvArtifacts changed size: add the field to VisitFields(SpirvArtifacts) (and ProgramArtifactsCodec.cpp's serializer), then update this number");
 #endif
 } // namespace MobileGL::MG_State::GLState

MobileGL/MG_State/GLState/ProgramState/ProgramArtifactsCodec.cpp

@@ -0,0 +1,303 @@
+// MobileGL - MobileGL/MG_State/GLState/ProgramState/ProgramArtifactsCodec.cpp
+// Copyright (c) 2025-2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+
+// ProgramArtifactsCodec.h. Compiled only under MOBILEGL_PIPE_PUSH (the root CMakeLists.txt
+// appends it inside `if (MOBILEGL_PIPE_PUSH)`), so the pull build gains no symbol from it.
+#include "ProgramArtifactsCodec.h"
+
+#include <bit>
+#include <cstring>
+#include <set>
+#include <string>
+#include <type_traits>
+#include <vector>
+
+namespace MobileGL::MG_State::GLState {
+    namespace {
+        // Little-endian, stated rather than assumed. Every ABI MobileGL ships on is
+        // little-endian; the day one is not, this is a compile error and not a silently
+        // byte-swapped reflection table.
+        static_assert(std::endian::native == std::endian::little,
+                      "the program-archive codec writes scalars in native order and MobileGL's "
+                      "ABIs are little-endian; a big-endian target needs explicit byte order");
+
+        // ---- the four container shapes the archive is built out of ----
+        //
+        // Detected by SHAPE rather than by naming std::vector / ska::flat_hash_map, because
+        // MobileGL's aliases are not all std:: types (UnorderedMap is ska::flat_hash_map) and
+        // a codec that named them would stop compiling the day one is swapped. The order the
+        // arms are tested in is what makes them unambiguous: String before every container,
+        // maps before sets (a map has both key_type and mapped_type), fixed arrays before
+        // resizable ones.
+        template <class T>
+        concept ArchiveString = std::same_as<T, String>;
+
+        template <class T>
+        concept ArchiveMap = requires {
+            typename T::key_type;
+            typename T::mapped_type;
+        };
+
+        template <class T>
+        concept ArchiveSet = requires { typename T::key_type; } && !ArchiveMap<T> && !ArchiveString<T>;
+
+        template <class T>
+        concept ArchiveFixedArray = requires { std::tuple_size<T>::value; };
+
+        template <class T>
+        concept ArchiveVector = !ArchiveString<T> && !ArchiveFixedArray<T> && requires(T& t) {
+            t.resize(SizeT{0});
+            t.size();
+            t.begin();
+        };
+
+        template <class T>
+        concept ArchiveScalar = std::is_arithmetic_v<T> || std::is_enum_v<T>;
+
+        // The ONE hand-written arm, and it is hand-written because ProgramArtifacts.h gives it
+        // no VisitFields table: glslang::TIntermediate::TUniformInitializer is a plain
+        // aggregate that merely LOOKS like a glslang type (std::string + scalars + two
+        // std::vectors), which is exactly what ProgramTranslationCache.h audited it as when it
+        // decided the archive holds no glslang-owned memory. If a field is added there, this
+        // arm and the format version below both have to move.
+        using UniformInitializer = glslang::TIntermediate::TUniformInitializer;
+
+        template <class T>
+        concept ArchiveUniformInitializer = std::same_as<T, UniformInitializer>;
+
+        // ---- the writer ----
+
+        template <class T>
+        void PutRaw(Vector<Uint8>& out, const T& value) {
+            static_assert(std::is_trivially_copyable_v<T>);
+            const SizeT at = out.size();
+            out.resize(at + sizeof(T));
+            std::memcpy(out.data() + at, &value, sizeof(T));
+        }
+
+        void PutCount(Vector<Uint8>& out, SizeT count) {
+            PutRaw(out, static_cast<Uint64>(count));
+        }
+
+        template <class T>
+        void WriteValue(Vector<Uint8>& out, const T& value);
+
+        template <class T>
+        void WriteSequence(Vector<Uint8>& out, const T& value) {
+            PutCount(out, value.size());
+            for (const auto& element : value) WriteValue(out, element);
+        }
+
+        template <class T>
+        void WriteValue(Vector<Uint8>& out, const T& value) {
+            if constexpr (ArchiveScalar<T>) {
+                PutRaw(out, value);
+            } else if constexpr (ArchiveString<T>) {
+                PutCount(out, value.size());
+                const SizeT at = out.size();
+                out.resize(at + value.size());
+                if (!value.empty()) std::memcpy(out.data() + at, value.data(), value.size());
+            } else if constexpr (ArchiveMap<T>) {
+                PutCount(out, value.size());
+                for (const auto& entry : value) {
+                    WriteValue(out, entry.first);
+                    WriteValue(out, entry.second);
+                }
+            } else if constexpr (ArchiveSet<T>) {
+                WriteSequence(out, value);
+            } else if constexpr (ArchiveFixedArray<T>) {
+                // No count: the width is part of the type, and writing one would let a reader
+                // believe a stream that disagrees with the struct.
+                for (const auto& element : value) WriteValue(out, element);
+            } else if constexpr (ArchiveVector<T>) {
+                WriteSequence(out, value);
+            } else if constexpr (ArchiveUniformInitializer<T>) {
+                WriteValue(out, value.name);
+                WriteValue(out, value.basicType);
+                WriteValue(out, value.vectorSize);
+                WriteValue(out, value.matrixCols);
+                WriteValue(out, value.matrixRows);
+                WriteValue(out, value.arraySize);
+                WriteValue(out, value.intValues);
+                WriteValue(out, value.floatValues);
+            } else {
+                // The archive's own structs: TypeFacts, ResourceReflection, XfbVarying. ONE
+                // table serves both directions, so a member added to any of them is carried by
+                // both halves of this codec the moment its VisitFields row is added - and a
+                // type with no table at all is a compile error here rather than a silently
+                // skipped field.
+                VisitFields(value, [&out](const char*, const auto& field) { WriteValue(out, field); });
+            }
+        }
+
+        // ---- the reader ----
+
+        struct ReadCursor {
+            const Uint8* Bytes = nullptr;
+            SizeT Size = 0;
+            SizeT Pos = 0;
+            Bool Ok = true;
+
+            SizeT Remaining() const { return Size - Pos; }
+        };
+
+        template <class T>
+        Bool TakeRaw(ReadCursor& in, T& value) {
+            static_assert(std::is_trivially_copyable_v<T>);
+            if (!in.Ok || in.Remaining() < sizeof(T)) {
+                in.Ok = false;
+                return false;
+            }
+            std::memcpy(&value, in.Bytes + in.Pos, sizeof(T));
+            in.Pos += sizeof(T);
+            return true;
+        }
+
+        // A COUNT IS CHECKED AGAINST THE BYTES THAT REMAIN BEFORE ANYTHING IS ALLOCATED. Every
+        // element this codec writes costs at least one byte, so a count larger than the
+        // remaining bytes cannot describe this stream - and refusing it here is what stops a
+        // corrupt or truncated archive from turning into a multi-gigabyte resize before the
+        // element loop notices it has run out.
+        Bool TakeCount(ReadCursor& in, SizeT& count) {
+            Uint64 raw = 0;
+            if (!TakeRaw(in, raw)) return false;
+            if (raw > static_cast<Uint64>(in.Remaining())) {
+                in.Ok = false;
+                return false;
+            }
+            count = static_cast<SizeT>(raw);
+            return true;
+        }
+
+        template <class T>
+        void ReadValue(ReadCursor& in, T& value);
+
+        template <class T>
+        void ReadValue(ReadCursor& in, T& value) {
+            if constexpr (ArchiveScalar<T>) {
+                TakeRaw(in, value);
+            } else if constexpr (ArchiveString<T>) {
+                SizeT count = 0;
+                if (!TakeCount(in, count)) return;
+                value.assign(reinterpret_cast<const char*>(in.Bytes + in.Pos), count);
+                in.Pos += count;
+            } else if constexpr (ArchiveMap<T>) {
+                SizeT count = 0;
+                if (!TakeCount(in, count)) return;
+                value.clear();
+                for (SizeT i = 0; i < count && in.Ok; ++i) {
+                    typename T::key_type key{};
+                    typename T::mapped_type mapped{};
+                    ReadValue(in, key);
+                    ReadValue(in, mapped);
+                    if (!in.Ok) return;
+                    value.emplace(Move(key), Move(mapped));
+                }
+            } else if constexpr (ArchiveSet<T>) {
+                SizeT count = 0;
+                if (!TakeCount(in, count)) return;
+                value.clear();
+                for (SizeT i = 0; i < count && in.Ok; ++i) {
+                    typename T::key_type key{};
+                    ReadValue(in, key);
+                    if (!in.Ok) return;
+                    value.insert(Move(key));
+                }
+            } else if constexpr (ArchiveFixedArray<T>) {
+                for (auto& element : value) {
+                    ReadValue(in, element);
+                    if (!in.Ok) return;
+                }
+            } else if constexpr (ArchiveVector<T>) {
+                SizeT count = 0;
+                if (!TakeCount(in, count)) return;
+                value.clear();
+                value.resize(count);
+                for (auto& element : value) {
+                    ReadValue(in, element);
+                    if (!in.Ok) return;
+                }
+            } else if constexpr (ArchiveUniformInitializer<T>) {
+                ReadValue(in, value.name);
+                ReadValue(in, value.basicType);
+                ReadValue(in, value.vectorSize);
+                ReadValue(in, value.matrixCols);
+                ReadValue(in, value.matrixRows);
+                ReadValue(in, value.arraySize);
+                ReadValue(in, value.intValues);
+                ReadValue(in, value.floatValues);
+            } else {
+                VisitFields(value, [&in](const char*, auto& field) {
+                    if (in.Ok) ReadValue(in, field);
+                });
+            }
+        }
+
+        // The struct-size echo. Under a toolchain whose sizes are not pinned yet
+        // (ProgramArtifacts.h's libc++ branch until the integrator fills it in) this is 0,
+        // which still round-trips within one build - the echo compares what THIS build wrote
+        // against what THIS build expects - and stops mattering the moment the pin lands.
+#ifdef MGL_LINKARTIFACTS_SIZE
+        inline constexpr Uint64 kLinkArtifactsSizeEcho = MGL_LINKARTIFACTS_SIZE;
+#else
+        inline constexpr Uint64 kLinkArtifactsSizeEcho = 0;
+#endif
+    } // namespace
+
+    void EncodeProgramArtifacts(const LinkArtifacts& link, const SpirvArtifacts& spirv,
+                                Vector<Uint8>& out) {
+        PutRaw(out, kProgramArtifactsCodecVersion);
+        PutRaw(out, kLinkArtifactsSizeEcho);
+        // `link` is walked through its own VisitFields table, which omits the live
+        // SharedPtr<glslang::TProgram>: 57 of the 58 members. There is no arm here for it and
+        // there must not be one - it points into a glslang arena that no archived instance
+        // owns, and ProgramTranslationCache asserts it is null at insert.
+        WriteValue(out, link);
+        WriteValue(out, spirv);
+    }
+
+    Bool DecodeProgramArtifacts(const Uint8* bytes, SizeT size, LinkArtifacts& link,
+                                SpirvArtifacts& spirv) {
+        // Both outputs are left in a DEFINED state on every exit, including every failure:
+        // a caller that ignores the return value gets an empty archive rather than half of a
+        // truncated one.
+        link = LinkArtifacts{};
+        spirv = SpirvArtifacts{};
+        if (bytes == nullptr) return false;
+
+        ReadCursor in{bytes, size, 0, true};
+        Uint32 version = 0;
+        Uint64 sizeEcho = 0;
+        if (!TakeRaw(in, version) || !TakeRaw(in, sizeEcho)) return false;
+        // REFUSED, NOT GUESSED. A different version word or a struct that changed width means
+        // the bytes describe a layout this build does not have; deserialising them anyway
+        // writes garbage into the tail of a reflection table, which is exactly the failure the
+        // two words exist to turn into a clean false.
+        if (version != kProgramArtifactsCodecVersion) return false;
+        if (sizeEcho != kLinkArtifactsSizeEcho) return false;
+
+        ReadValue(in, link);
+        ReadValue(in, spirv);
+        if (!in.Ok) {
+            link = LinkArtifacts{};
+            spirv = SpirvArtifacts{};
+            return false;
+        }
+        // Trailing bytes are a mismatch too: the format accounts for every byte it writes, so
+        // anything left over means the reader and the writer disagree about the shape and the
+        // agreement so far was luck.
+        if (in.Pos != in.Size) {
+            link = LinkArtifacts{};
+            spirv = SpirvArtifacts{};
+            return false;
+        }
+        // Never written, never read, and stated here so it cannot be added by reflex.
+        link.program = nullptr;
+        return true;
+    }
+} // namespace MobileGL::MG_State::GLState

MobileGL/MG_State/GLState/ProgramState/ProgramArtifactsCodec.h

@@ -0,0 +1,76 @@
+// MobileGL - MobileGL/MG_State/GLState/ProgramState/ProgramArtifactsCodec.h
+// Copyright (c) 2025-2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+
+#pragma once
+#include "ProgramArtifacts.h"
+
+// The reflection ARCHIVE's serializer (P4a, D-H2): create_shader_state's payload is per-stage
+// SPIR-V plus LinkArtifacts + SpirvArtifacts, whole structs, and until now nothing could turn
+// those into bytes. Every VisitFields comment in ProgramArtifacts.h said "(and its serializer
+// when one exists)"; this is it.
+//
+// IT LIVES BESIDE THE HEADER RATHER THAN INSIDE IT, deliberately: ProgramArtifacts.h carries
+// the check_include_closure.py "artifacts-header" probe, which pins that the header is
+// glslang-free by symbol and reaches no ShaderObject, no SpvcSession, no Config and no
+// MG_Backend. A codec inside it would have to be inspected against that probe on every edit;
+// a codec beside it leaves the probe untouched, and this file is compiled only in a push
+// build (the root CMakeLists.txt appends it inside `if (MOBILEGL_PIPE_PUSH)`).
+//
+// WHEN IT ACTUALLY RUNS, and the answer is "not on the monolith hot path at all". In monolith
+// the archive does not travel: MGPProgramDesc's seven blob refs are declared with Size 0 -
+// "this record does not declare its blob" - and MGPipeApplyCreateShaderState takes the two
+// structs by pointer beside the record, so the applier reads the frontend's own archive and
+// this codec is never called. The VERIFY build is where it is exercised, and it is exercised
+// as LIVE CODE WITH A GATE rather than as dead code with a unit test: the applier serialises,
+// deserialises and field-compares before storing, and a mismatch is
+// Fatal{PipeVerifyDiffer, "program-archive"}. Under split, P5 is what makes it the transport's
+// path.
+//
+// THE FORMAT, and every part of it is a refusal rather than a guess:
+//   * a VERSION word first, and a MGL_LINKARTIFACTS_SIZE echo second, so a struct that gained
+//     a field and a codec that did not is a MISMATCH AT READ TIME rather than a silent
+//     truncation that deserialises garbage into the tail of a reflection table;
+//   * length-prefixed everything - strings, vectors, maps, sets - with the count checked
+//     against the bytes that remain before a single element is allocated, so a corrupt count
+//     cannot turn into a four-billion-element resize;
+//   * little-endian, which is asserted rather than assumed;
+//   * and `LinkArtifacts::program` is NEVER visited. It is the live glslang TProgram, it is
+//     null for every archived instance by construction, and VisitFields deliberately omits it
+//     (57 of the 58 members). Decode leaves it null.
+namespace MobileGL::MG_State::GLState {
+
+    // Bumped whenever the byte format changes in a way a previous reader would misread. A
+    // reader that sees a different word REFUSES; it never tries to guess a layout.
+    inline constexpr Uint32 kProgramArtifactsCodecVersion = 1;
+
+    // Appends the archive to `out` (which is not cleared, so a caller may frame it). Never
+    // fails: everything it walks is owned plain data.
+    void EncodeProgramArtifacts(const LinkArtifacts& link, const SpirvArtifacts& spirv,
+                                Vector<Uint8>& out);
+
+    // Replaces `link` and `spirv` with what `bytes` describes. Returns false - with both
+    // outputs left in a defined, default state - for a truncated stream, a version mismatch, a
+    // struct-size mismatch, or trailing bytes the format does not account for. `link.program`
+    // is always null on return.
+    Bool DecodeProgramArtifacts(const Uint8* bytes, SizeT size, LinkArtifacts& link,
+                                SpirvArtifacts& spirv);
+
+    // How many fields a type's VisitFields table actually visits. The codec walks exactly that
+    // table, so this is what pins "the codec did not quietly grow an arm of its own" - most of
+    // all for LinkArtifacts, whose 58th member is the live TProgram the table omits. It is a
+    // runtime count rather than a static_assert because VisitFields needs an INSTANCE and
+    // these structs carry strings, vectors and maps: none of them is a constant expression.
+    // ProgramArtifactsCodecTest is where it is asserted.
+    template <class T>
+    inline SizeT ProgramArtifactsVisitedFieldCount() {
+        T probe{};
+        SizeT count = 0;
+        VisitFields(probe, [&count](const char*, auto&) { ++count; });
+        return count;
+    }
+} // namespace MobileGL::MG_State::GLState

MobileGL/MG_State/GLState/ProgramState/ProgramObject.cpp

@@ -14,6 +14,7 @@
 #include <MG_Util/Async/ShaderCompilePool.h>
 #include <MG_Util/Converters/GLToStr/GLEnumConverter.h>
 #include <MG_Util/ShaderTranspiler/CompileEnv.h>
+#include <MG_Pipe/PipeMutation.h>
 #include <MG_State/GLState/StateObjectDeathNotice.h>
 
 const char* kDefaultFragmentShaderSource = R"(#version 460 core
@@ -40,7 +41,21 @@ namespace MobileGL::MG_State::GLState {
         // object no longer exists to be passed, and because the lifetime id is what the client
         // slot allocator resolves the handle from. No-op unless a backend registered the ops
         // (a pull build declares none at all).
-        NotifyStateObjectDestroyed(MG_Pipe::MGPipeKind::ShaderCso, m_lifetimeId);
+        //
+        // P4a D-I1: the notice is no longer raised directly - it is step 2 of the ONE
+        // client-side death helper for this kind, which emits delete_shader_state first,
+        // raises the notice second and frees the slot last. The client mints the ShaderCso, so
+        // the client is where its death has to be spoken from: a backend death-ops table is a
+        // redundant, idempotent SECOND path, and under a backend that installs none it was
+        // previously the ONLY one, which is how a slot leaks for the life of the process.
+        //
+        // AN ORDINARY PROGRAM AND A PIPELINE COMPOSITE TAKE THIS SAME LINE. A composite is an
+        // ordinary ProgramObject with its own lifetime id, its slot merely comes out of the
+        // reserved band, and its OTHER release path - the pipeline cache dropping it when the
+        // draw-program signature moves - goes through the same helper. Whichever runs second is
+        // a proven no-op, because the slot allocator refuses a slot that is not live at that
+        // generation.
+        MG_Pipe::MGPipeEmitShaderCsoDestroyAndFree(m_lifetimeId);
 #endif
     }
 

MobileGL/MG_State/GLState/ProgramState/ProgramObject.h

@@ -1111,6 +1111,23 @@ namespace MobileGL::MG_State::GLState {
             return Artifacts();
         }
 
+#if MOBILEGL_PIPE_PUSH
+        // The phase-B twin of GetLinkReflection, and it exists for exactly one caller:
+        // create_shader_state publishes the WHOLE SpirvArtifacts beside the whole
+        // LinkArtifacts, because the archive the far side deserialises into is those two
+        // structs and nothing else. The granular getters above (GetGeneratedSpirv,
+        // GetSpirvStatus, UsesNativeFloat64, PointSizeDemoted, GetSpirvValidationEnabled,
+        // GetUBOSize) cover what the GL layer needs and deliberately do not reach
+        // reservedNumSamplesOffset or uniformOffsets, which the descriptor does need.
+        //
+        // PUSH-ONLY, so a pull build's symbol set and this class's layout are byte-for-byte
+        // what they were: an inline const-ref accessor adds nothing to a pull build that is
+        // never compiled into one. It joins both phases, like every other Spirv() reader.
+        const SpirvArtifacts& GetSpirvReflection() const {
+            return Spirv();
+        }
+#endif
+
         static Bool IsValidUniformLocation(const LinkArtifacts& artifacts, Int location) {
             if (location < 0 || location > static_cast<Int>(artifacts.maxUniformLocation)) return false;
             if (static_cast<SizeT>(location) >= artifacts.uniformIndexInTProgram.size()) return false;

MobileGL/MG_State/GLState/RenderbufferState/RenderbufferObject.cpp

@@ -9,6 +9,10 @@
 #include "RenderbufferObject.h"
 #include <MG_Util/Metrics/TextureMetrics.h>
 #include <MG_State/GLState/StateObjectDeathNotice.h>
+// The contract's own door, exactly as the texture half takes it (c0b): the four renderbuffer
+// hooks this file calls are declared in MG_Pipe/PipeMutation.h and defined in
+// MG_Impl/Pipe/PipeFill.cpp, so no MG_State translation unit includes the client's emitter.
+#include <MG_Pipe/PipeMutation.h>
 
 #include <atomic>
 
@@ -25,19 +29,33 @@ namespace MobileGL {
                 return g_nextRenderbufferLifetimeId.fetch_add(1, std::memory_order_relaxed);
             }
 
-            RenderbufferObject::RenderbufferObject(Uint externalIndex) : m_externalIndex(externalIndex) {}
+            RenderbufferObject::RenderbufferObject(Uint externalIndex) : m_externalIndex(externalIndex) {
+#if MOBILEGL_PIPE_PUSH
+                // P4a D-D1: resource_create from the constructor, carrying no storage. A
+                // renderbuffer is an INDEPENDENT class on the wire - it shares MGPResourceDesc's
+                // shape with textures and buffers and nothing else - and its handle is minted
+                // whatever the subsystem bitmask says, because MGPSurface::Res names it out of the
+                // framebuffer subsystem.
+                // TWO CALLS AND NOT ONE (c0b): the mint is unconditional in a push build
+                // because a renderbuffer is named by handle out of the framebuffer subsystem
+                // whether or not its own family is switched on; the create is what the gate in
+                // PipeFill.cpp decides.
+                MG_Pipe::MGPipeMintRenderbufferHandle(*this);
+                MG_Pipe::MGPipeEmitRenderbufferResourceCreate(*this);
+#endif
+            }
 
 #if MOBILEGL_PIPE_PUSH
             RenderbufferObject::~RenderbufferObject() {
-                // P2 step e2: ANNOUNCE the death instead of leaving the backend to discover it in a
-                // garbage sweep. This is the last SharedPtr to this object dropping - not
-                // glDeleteRenderbuffers, which only marks the name and leaves a still-bound object very much
-                // alive - so it is the exact moment the backend's twin, and the driver storage that
-                // twin owns, stop being reachable. The notice carries the lifetime id because the
-                // object no longer exists to be passed, and because the lifetime id is what the client
-                // slot allocator resolves the handle from. No-op unless a backend registered the ops
-                // (a pull build declares none at all).
-                NotifyStateObjectDestroyed(MG_Pipe::MGPipeKind::Renderbuffer, m_lifetimeId);
+                // P4a D-I1, the fixed three-step order: the wire delete first (published-gated,
+                // because a slot is not evidence of a record), then the death notice - the P2
+                // step-e2 announcement that used to stand here alone, raised while the handle
+                // still resolves - and the slot last. Steps 2 and 3 are the contract's helper;
+                // step 1 is this package's, one statement earlier, because the helper's file
+                // belongs to the contract package for the whole phase.
+                // All three steps are the contract's helper (c0b); v1's separate step-1 call
+                // is deleted, not kept, for the reason ~TextureObjectBase states in full.
+                MG_Pipe::MGPipeEmitRenderbufferDestroyAndFree(m_lifetimeId);
             }
 #endif
 
@@ -96,17 +114,53 @@ namespace MobileGL {
             void RenderbufferObject::SetInternalFormat(TextureInternalFormat format) {
                 m_internalFormat = format;
                 m_componentSizes = MG_Util::GetComponentSizesForInternalFormat(format);
+#if MOBILEGL_PIPE_PUSH
+                PipePublishDescriptor();
+#endif
             }
 
             void RenderbufferObject::AllocateStorage(IntVec2 size) {
                 m_width = size.x();
                 m_height = size.y();
                 m_allocated = true;
+#if MOBILEGL_PIPE_PUSH
+                PipePublishDescriptor();
+#endif
             }
 
             void RenderbufferObject::SetSamples(Int samples) {
                 m_samples = samples;
+#if MOBILEGL_PIPE_PUSH
+                PipePublishDescriptor();
+#endif
             }
+
+#if MOBILEGL_PIPE_PUSH
+            // D-D2: THE RENDERBUFFER PUBLICATION HOLE, CLOSED BY EMISSION AND NOT BY A NEW
+            // VERSION. These three setters bump no version and raise no notice, so
+            // `glBindRenderbuffer; glRenderbufferStorage(newSize)` on an attached renderbuffer
+            // was invisible to everything downstream. Emitting from the storage entry point
+            // closes the RESOURCE half; a version counter here would resize the pull build's
+            // object and break G1.
+            //
+            // THE FRAMEBUFFER HALF IS THE AGGREGATE BUMP BELOW (P4a fable seam F-3), and the
+            // sentence that used to end the paragraph above - "widening the shutter would fire
+            // the framebuffer emission on an unrelated renderbuffer write" - was the seam:
+            // set_framebuffer_state inlines an attachment's InternalFormat, extent and Samples at
+            // emission (D-C1), so re-storaging an ATTACHED renderbuffer left the framebuffer
+            // record - and the handle arm's four cross-object masks - describing the previous
+            // storage while the resource record described the new one. The bump costs one
+            // framebuffer re-emission per storage definition, whether or not the object is
+            // attached, which the emitter's content hash suppresses when nothing it inlines
+            // moved; it is not a counter on this object.
+            //
+            // The emitter dedupes on the built descriptor, so glRenderbufferStorage's three-setter
+            // sequence publishes once rather than three times.
+            void RenderbufferObject::PipePublishDescriptor() {
+                MG_Pipe::MGPipeEmitRenderbufferResourceRespecify(*this);
+                MGP_NOTE_AGGREGATE(FramebufferAttachment);
+            }
+#endif
         } // namespace GLState
     } // namespace MG_State
 } // namespace MobileGL

MobileGL/MG_State/GLState/RenderbufferState/RenderbufferObject.h

@@ -59,6 +59,13 @@ namespace MobileGL {
 
             private:
                 static Uint64 AllocateLifetimeId();
+#if MOBILEGL_PIPE_PUSH
+                // P4a D-D2: resource_respecify, from every storage-defining setter. Non-virtual
+                // and push-only, so the pull build's object layout is untouched (P4a's
+                // admitted-resize set is EMPTY); defined in RenderbufferObject.cpp, which is the
+                // one translation unit that includes the client emitter.
+                void PipePublishDescriptor();
+#endif
 
                 Uint m_externalIndex = 0;
                 const Uint64 m_lifetimeId = AllocateLifetimeId();

MobileGL/MG_State/GLState/SamplerState/SamplerObject.cpp

@@ -36,7 +36,22 @@ namespace MobileGL {
                 // because the object no longer exists to be passed, and because the lifetime id
                 // is what the client slot allocator resolves the handle from. No-op unless a
                 // backend registered the ops (a pull build declares none at all).
-                NotifyStateObjectDestroyed(MG_Pipe::MGPipeKind::SamplerCso, m_lifetimeId);
+                //
+                // P4a D-I1: the notice is no longer raised directly - it is step 2 of the ONE
+                // client-side death helper for this kind, which emits delete_sampler_state
+                // first, raises the notice second and frees the slot last. Making the client
+                // the only death path is what stops a slot leaking under a backend that
+                // installs no death-ops table at all, and the backend's own notice becomes a
+                // redundant, idempotent second path rather than the only one.
+                //
+                // FOR A CONTENT-ADDRESSED SAMPLER CSO THIS HELPER CORRECTLY FREES NOTHING, and
+                // that is the design rather than a gap: the CSO belongs to a VALUE, not to this
+                // object (two identical SamplerObjects share one), so it is allocated with no
+                // lifetime id, the helper resolves nothing for this one, and the only death
+                // path for that slot is the CSO cache's LRU eviction - which is client-side and
+                // therefore backend-neutral on day one. What still goes out, unconditionally
+                // and exactly as before, is the notice.
+                MG_Pipe::MGPipeEmitSamplerCsoDestroyAndFree(m_lifetimeId);
             }
 #endif
 

MobileGL/MG_State/GLState/TextureState/TextureObject.cpp

@@ -12,6 +12,13 @@
 #include "MG_Util/Types.h"
 #include <MG_Util/Metrics/TextureMetrics.h>
 #include <MG_Pipe/PipeMutation.h>
+// NO MG_State TRANSLATION UNIT SEES THE CLIENT'S EMITTER ANY MORE (c0b, ID-13). v1 included
+// MG_Impl/Pipe/TextureEmit.h here and in RenderbufferObject.cpp because at the contract tag
+// MG_Pipe/PipeMutation.h carried no texture row; it now declares the four mints, the nine
+// emissions and the publication latch, so this file sees a DECLARATION exactly as
+// BufferObject.cpp does and the closure gate's mutation-header probe has nothing to find.
+// The three PipePublish* helpers stay on TextureObjectBase so the cube's, the view's and the
+// buffer texture's translation units keep calling an inherited member.
 
 namespace MobileGL {
     namespace MG_State {
@@ -29,15 +36,79 @@ namespace MobileGL {
 
 #if MOBILEGL_PIPE_PUSH
             TextureObjectBase::~TextureObjectBase() {
-                // P2 step e2: ANNOUNCE the death instead of leaving the backend to discover it in a
-                // garbage sweep. This is the last SharedPtr to this object dropping - not the
-                // glDelete* that only marks the name and leaves a still-bound object very much
-                // alive - so it is the exact moment the backend's twin, and the driver storage
-                // that twin owns, stop being reachable. The notice carries the lifetime id
-                // because the object no longer exists to be passed, and because the lifetime id
-                // is what the client slot allocator resolves the handle from. No-op unless a
-                // backend registered the ops (a pull build declares none at all).
-                NotifyStateObjectDestroyed(MG_Pipe::MGPipeKind::Texture, m_lifetimeId);
+                // P4a D-I1: BACKEND-NEUTRAL FROM DAY ONE, and the three-step order is fixed.
+                //
+                //   1. the wire delete FIRST - it drops the applier's record while the record
+                //      still exists, so a recycled slot cannot inherit a field. Published-gated
+                //      rather than slot-gated: a backend twin table mints a slot through
+                //      MGPipeSlots().Acquire whether or not the subsystem ever asked this client
+                //      to emit a create, and a resource_destroy on such a handle is a refused
+                //      call the applier counts and asserts on;
+                //   2. the death notice SECOND - it resolves the handle through the allocator,
+                //      and a backend told after the free could no longer find its twin. This is
+                //      the P2 step-e2 announcement that used to stand here alone: the last
+                //      SharedPtr to this object dropping, not the glDelete* that only marks the
+                //      name and leaves a still-bound object very much alive;
+                //   3. the slot LAST, and a double free on a stale generation is a proven no-op.
+                //
+                // ALL THREE STEPS ARE THE CONTRACT'S HELPER (c0b): it reads the publication
+                // latch, emits the resource_destroy itself, raises the notice while the handle
+                // still resolves and frees the slot last. v1 emitted step 1 from a second
+                // statement here because at the tag the helper hard-coded `published = false`;
+                // that statement is deleted rather than kept, since a second delete for a
+                // record the helper has already dropped is a refused call the applier asserts
+                // on. The SamplerViewCso minted off this same lifetime id goes with it. The
+                // BUILT-IN SAMPLER does not: it is a real SamplerObject with its own lifetime
+                // id and its own destructor, which takes the same helper shape.
+                MG_Pipe::MGPipeEmitTextureDestroyAndFree(m_lifetimeId);
+            }
+
+            // ---- P4a's three client emission points (see TextureObject.h) ----
+
+            void TextureObjectBase::PipePublishDescriptor() {
+                MG_Pipe::MGPipeEmitTextureResourceRespecify(*this, MG_Pipe::MGPipeTextureRespecifyScope::WholeResource,
+                                                            0, 0);
+                // AND THE FRAMEBUFFER AGGREGATE MOVES (P4a fable seam F-3). The resource record
+                // above is only half of what a storage definition changes: set_framebuffer_state
+                // INLINES an attachment's InternalFormat, TextureTarget, extent, Samples and
+                // Complete at emission (D-C1), so redefining the storage of a texture that is
+                // ATTACHED changed those fields with nothing bit 11 reads moving - the format
+                // and shape setters bump the two TEXTURE aggregates and never the attachment
+                // one, and no path from a texture reaches its framebuffers. The handle arm then
+                // answered its four cross-object masks from the stale copy while the legacy arm
+                // re-read the frontend at the same re-sync. This is the one funnel every
+                // storage-defining entry point takes (see AllocateStorage), so the bump lives
+                // here and not per setter, it is push-only like the rest of this block, and it
+                // over-fires the framebuffer bit once per storage definition of an unattached
+                // texture - at load time, where a 304-byte hash is nothing.
+                MGP_NOTE_AGGREGATE(FramebufferAttachment);
+            }
+
+            void TextureObjectBase::PipePublishLevelDescriptor(TextureUploadTarget uploadTarget, Uint mipmapLevel) {
+                // ONE level was (re)allocated: only that level's pending upload is against
+                // storage that is gone (P4a final review C-1). Every other level's stays.
+                MG_Pipe::MGPipeEmitTextureResourceRespecify(*this, MG_Pipe::MGPipeTextureRespecifyScope::OneLevel,
+                                                            static_cast<Uint32>(uploadTarget),
+                                                            static_cast<Uint32>(mipmapLevel));
+                MGP_NOTE_AGGREGATE(FramebufferAttachment); // an attached level's extent is inlined (F-3)
+            }
+
+            void TextureObjectBase::PipePublishTruncatedDescriptor(TextureUploadTarget uploadTarget, Uint levelCount) {
+                // The chain was cut at `levelCount`: the levels above the cut are gone with their
+                // pending uploads, the levels below it are untouched and keep theirs.
+                MG_Pipe::MGPipeEmitTextureResourceRespecify(*this, MG_Pipe::MGPipeTextureRespecifyScope::LevelsFrom,
+                                                            static_cast<Uint32>(uploadTarget),
+                                                            static_cast<Uint32>(levelCount));
+                MGP_NOTE_AGGREGATE(FramebufferAttachment);
+            }
+
+            void TextureObjectBase::PipePublishParams() {
+                MG_Pipe::MGPipeEmitTextureParams(*this);
+            }
+
+            void TextureObjectBase::PipeNoteLevelDirty(TextureUploadTarget uploadTarget, Uint mipmapLevel) {
+                MG_Pipe::MGPipeNoteTextureLevelDirty(*this, static_cast<Uint32>(uploadTarget),
+                                                     static_cast<Uint32>(mipmapLevel));
             }
 #endif
 
@@ -69,6 +140,34 @@ namespace MobileGL {
                     m_sampler->SetWrapT(SamplerWrapMode::ClampToEdge);
                     m_sampler->SetWrapR(SamplerWrapMode::ClampToEdge);
                 }
+#if MOBILEGL_PIPE_PUSH
+                // P4a D-D1: A RESOURCE EXISTS BEFORE ANYTHING CAN NAME IT, so resource_create is
+                // emitted from the constructor and carries no storage - the store is defined
+                // lazily by the first respecify and every backend already tolerates a resource
+                // with none. The handle itself is minted whatever the subsystem bitmask says,
+                // because set_framebuffer_state and set_sampler_views name this texture by handle
+                // out of two different subsystems.
+                //
+                // NOTHING THE DERIVED CLASS IMPLEMENTS IS TOUCHED HERE and that is a
+                // correctness requirement rather than a style: the derived object does not exist
+                // yet, so ITextureObject::GetStorageType and ::GetUploadTargets - PURE, with no
+                // body on this base - would be undefined behaviour. The emitter reads GetTarget()
+                // and GetExternalIndex(), which TextureObjectBase itself overrides and which
+                // therefore dispatch to this class's own bodies over members the mem-init list
+                // has already written; the storage kind is derived from the target, which is
+                // exact (TextureObjectBuffer is the only class that reports Buffer and
+                // TextureBuffer is the only target it is constructed with).
+                //
+                // TWO CALLS AND NOT ONE (c0b): the MINT is unconditional in a push build -
+                // set_framebuffer_state and set_sampler_views name this texture by handle out of
+                // two other subsystems, so gating it would make them emit null handles in exactly
+                // the A/B arm that exists to isolate the families - and the CREATE is what the
+                // subsystem gate in PipeFill.cpp decides.
+                (void)target;
+                (void)externalIndex;
+                MG_Pipe::MGPipeMintTextureHandle(*this);
+                MG_Pipe::MGPipeEmitTextureResourceCreate(*this);
+#endif
             }
 
             TextureInternalFormat TextureObjectBase::GetFormat() const {
@@ -116,6 +215,14 @@ namespace MobileGL {
                 BumpShapeVersion();
                 ++m_textureParamsVersion;
                 MGP_NOTE_AGGREGATE(TextureParams);
+#if MOBILEGL_PIPE_PUSH
+                // The format is BOTH halves: a descriptor field the backend allocates from and a
+                // parameter the swizzle / depth-stencil push reads, so both records move. It is
+                // also the last statement of both glTexBuffer entry points, which is what
+                // publishes a buffer texture's window without a call site in MG_Impl/GLImpl.
+                PipePublishDescriptor();
+                PipePublishParams();
+#endif
             }
 
             Uint TextureObjectBase::GetExternalIndex() const {
@@ -142,6 +249,9 @@ namespace MobileGL {
                 m_sampler->SetBorderColor(color);
                 ++m_textureParamsVersion;
                 MGP_NOTE_AGGREGATE(TextureParams);
+#if MOBILEGL_PIPE_PUSH
+                PipePublishParams();
+#endif
             }
 
             const IntVec4& TextureObjectBase::GetBorderColorI() const {
@@ -157,6 +267,9 @@ namespace MobileGL {
                 m_sampler->SetBorderColorI(color);
                 ++m_textureParamsVersion;
                 MGP_NOTE_AGGREGATE(TextureParams);
+#if MOBILEGL_PIPE_PUSH
+                PipePublishParams();
+#endif
             }
 
             const UintVec4& TextureObjectBase::GetBorderColorUI() const {
@@ -172,6 +285,9 @@ namespace MobileGL {
                 m_sampler->SetBorderColorUI(color);
                 ++m_textureParamsVersion;
                 MGP_NOTE_AGGREGATE(TextureParams);
+#if MOBILEGL_PIPE_PUSH
+                PipePublishParams();
+#endif
             }
 
             BorderColorForm TextureObjectBase::GetBorderColorForm() const {
@@ -222,6 +338,9 @@ namespace MobileGL {
                 }
                 ++m_textureParamsVersion;
                 MGP_NOTE_AGGREGATE(TextureParams);
+#if MOBILEGL_PIPE_PUSH
+                PipePublishParams();
+#endif
             }
 
             void TextureObjectBase::SetSwizzleParamRGBA(const Vec4<TextureSwizzleParam>& values) {
@@ -230,6 +349,9 @@ namespace MobileGL {
                 m_swizzleParams = values;
                 ++m_textureParamsVersion;
                 MGP_NOTE_AGGREGATE(TextureParams);
+#if MOBILEGL_PIPE_PUSH
+                PipePublishParams();
+#endif
             }
 
             const UintVec2& TextureObjectBase::GetLevelRange() const {
@@ -249,6 +371,12 @@ namespace MobileGL {
                 ++m_textureParamsVersion;
                 MGP_NOTE_AGGREGATE(TextureParams);
                 BumpShapeVersion();
+#if MOBILEGL_PIPE_PUSH
+                // The level range is PARAMS, not a descriptor field: the record carries
+                // BaseLevel / MaxLevel and the storage is untouched. The descriptor is deduped on
+                // its own bytes, so the shape bump above costs nothing here.
+                PipePublishParams();
+#endif
             }
 
             void TextureObjectBase::SetMaxLevel(Uint maxLevel) {
@@ -261,6 +389,9 @@ namespace MobileGL {
                 ++m_textureParamsVersion;
                 MGP_NOTE_AGGREGATE(TextureParams);
                 BumpShapeVersion();
+#if MOBILEGL_PIPE_PUSH
+                PipePublishParams();
+#endif
             }
 
             Bool TextureObjectBase::IsImmutable() const {
@@ -281,6 +412,14 @@ namespace MobileGL {
                 }
                 ++m_textureParamsVersion;
                 MGP_NOTE_AGGREGATE(TextureParams);
+#if MOBILEGL_PIPE_PUSH
+                // Immutable is a descriptor fact the backend reads - and NOT a request for an
+                // acknowledgement: MGPipeResourceRespecifyNeedsAck names the buffer target
+                // explicitly, because texture allocation is lazy in monolith and stays lazy in
+                // split. The level clamp above is params.
+                PipePublishDescriptor();
+                PipePublishParams();
+#endif
             }
 
             Uint16 TextureObjectBase::GetTextureParamsVersion() const {
@@ -319,6 +458,9 @@ namespace MobileGL {
                 m_samples = samples;
                 ++m_textureParamsVersion;
                 MGP_NOTE_AGGREGATE(TextureParams);
+#if MOBILEGL_PIPE_PUSH
+                PipePublishDescriptor();
+#endif
             }
 
             Bool TextureObjectBase::HasFixedSampleLocations() const {
@@ -329,6 +471,9 @@ namespace MobileGL {
                 m_fixedSampleLocations = fixedSampleLocations;
                 ++m_textureParamsVersion;
                 MGP_NOTE_AGGREGATE(TextureParams);
+#if MOBILEGL_PIPE_PUSH
+                PipePublishDescriptor();
+#endif
             }
 
             Uint64 TextureObjectBase::GetLifetimeId() const {
@@ -360,11 +505,27 @@ namespace MobileGL {
                                                              MipmapInput input) {
                 BumpShapeVersion();
                 m_textureStorage.AllocateLevel(GetIndexOfTextureUploadTarget(uploadTarget), mipmapLevel, input);
+#if MOBILEGL_PIPE_PUSH
+                // AFTER the allocation, never before: BumpShapeVersion runs first and a descriptor
+                // built there would describe the level set this call is about to change. Every
+                // storage-defining GL entry point - glTexImage*, glCompressedTexImage*,
+                // glTexStorage*, glTextureView and the generated-mip storage grow - reaches
+                // storage through here, which is what makes the emission complete without one call
+                // site per entry point in MG_Impl/GLImpl. AND IT NAMES THE LEVEL (final review
+                // C-1): this call replaced ONE level's storage, and only that level's pending
+                // upload may go with it.
+                PipePublishLevelDescriptor(uploadTarget, mipmapLevel);
+#endif
             }
 
             void TextureObjectWithOneMipmap::TruncateMipmapLevels(TextureUploadTarget uploadTarget, Uint levelCount) {
                 BumpShapeVersion();
                 m_textureStorage.TruncateToLevelCount(GetIndexOfTextureUploadTarget(uploadTarget), levelCount);
+#if MOBILEGL_PIPE_PUSH
+                // The levels at and above the cut are gone; the ones below keep their pending
+                // uploads (final review C-1).
+                PipePublishTruncatedDescriptor(uploadTarget, levelCount);
+#endif
             }
 
             void TextureObjectWithOneMipmap::UpdateMipmapSubData(TextureUploadTarget uploadTarget, Uint mipmapLevel,
@@ -383,6 +544,11 @@ namespace MobileGL {
                     MGP_NOTE_AGGREGATE(TextureContent);
                 }
                 m_textureStorage.MarkDirty(GetIndexOfTextureUploadTarget(uploadTarget), mipmapLevel, dirty);
+#if MOBILEGL_PIPE_PUSH
+                // THE DRAIN LIST HAS NO CLEAN ARM (see TextureEmit.h): a level that goes clean
+                // is collected at the next drain, whose first test is IsStorageDirty.
+                if (dirty) PipeNoteLevelDirty(uploadTarget, mipmapLevel);
+#endif
             }
 
             Bool TextureObjectWithOneMipmap::IsStorageDirty(TextureUploadTarget uploadTarget, Uint mipmapLevel) const {
@@ -395,6 +561,13 @@ namespace MobileGL {
                 MGP_NOTE_AGGREGATE(TextureContent);
                 m_textureStorage.MarkDirtyRegion(GetIndexOfTextureUploadTarget(uploadTarget), mipmapLevel, offset,
                                                  size);
+#if MOBILEGL_PIPE_PUSH
+                // THE DRAIN LIST IS KEYED ON THE STORAGE OWNER FOR FREE: TextureObjectView
+                // forwards this call to the OWNER's method after remapping the level and the
+                // region, so an upload through a view and an upload through the owner arrive here
+                // on the same object with the same owner-side coordinates.
+                PipeNoteLevelDirty(uploadTarget, mipmapLevel);
+#endif
             }
 
             MipmapDirtyRegion TextureObjectWithOneMipmap::GetStorageDirtyRegion(TextureUploadTarget uploadTarget,

MobileGL/MG_State/GLState/TextureState/TextureObject.h

@@ -190,6 +190,12 @@ namespace MobileGL::MG_State::GLState {
             m_depthStencilTextureMode = mode;
             ++m_textureParamsVersion;
             MGP_NOTE_AGGREGATE(TextureParams);
+#if MOBILEGL_PIPE_PUSH
+            // D-E3's whole point, at the one site that proves it: the depth-stencil mode of a
+            // texture that is ONLY the READ framebuffer's attachment reaches the driver, because
+            // set_texture_params is addressed by resource and is independent of every binding.
+            PipePublishParams();
+#endif
         }
 
     protected:
@@ -201,6 +207,46 @@ namespace MobileGL::MG_State::GLState {
         // otherwise invisible to such a memo (no bind moved).
         void BumpShapeVersion();
 
+#if MOBILEGL_PIPE_PUSH
+        // ---- P4a's client emission points (brief D-D1, D-D3, D-E1, D-I1) ----
+        //
+        // NON-VIRTUAL AND PUSH-ONLY, both deliberately: a virtual would grow the vtable and a
+        // member would grow the object, and P4a's admitted-resize set is EMPTY - every edit
+        // that reaches the pull build is inside this guard, so the pull build's symbol set is
+        // byte-for-byte the one it had before the phase.
+        //
+        // DECLARED HERE AND DEFINED IN TextureObject.cpp, which calls the contract's own hooks
+        // in MG_Pipe/PipeMutation.h - the same door BufferObject.cpp uses, and no MG_State
+        // translation unit sees MG_Impl/Pipe/TextureEmit.h at all (c0b, ID-13). They stay
+        // members rather than free calls so the cube's, the view's and the buffer texture's
+        // translation units keep calling an inherited helper.
+        //
+        // resource_respecify, WHOLE-RESOURCE scope: the format setter and the three parameter
+        // setters that move a DESCRIPTOR field without moving the shape (immutable levels,
+        // sample count, fixed sample locations), and a view's creation. The emitter dedupes
+        // this form on the built descriptor, so an over-call costs one 88-byte compare and
+        // never an extra record.
+        void PipePublishDescriptor();
+        // The PER-LEVEL and the CHAIN-CUT forms of the same call (P4a final review C-1). The
+        // applier keeps a pending-upload set per (uploadTarget, level) and drops the entries
+        // against the storage a respecify REPLACES - and the descriptor cannot tell it which:
+        // AllocateStorage is per level and TruncateMipmapLevels removes a tail, while the
+        // descriptor carries the base extent and the level count only. So the storage entry
+        // points state the scope themselves; the whole-resource form above is for the calls
+        // that really redefine the whole store. A per-level form is NOT deduped on the
+        // descriptor: a non-base level redefined at a new size moves no descriptor field, and
+        // the applier's box against the old level has to go regardless.
+        void PipePublishLevelDescriptor(TextureUploadTarget uploadTarget, Uint mipmapLevel);
+        void PipePublishTruncatedDescriptor(TextureUploadTarget uploadTarget, Uint levelCount);
+        // set_texture_params, from every mutator that bumps m_textureParamsVersion.
+        void PipePublishParams();
+        // The sub-data DRAIN LIST's append, on a level's first dirty mark. There is no clean
+        // arm: the contract's hook (MG_Pipe/PipeMutation.h) carries no `dirty` flag, and a
+        // level that goes clean is collected at the next drain, where !IsStorageDirty is the
+        // first test EmitOneLevel makes.
+        void PipeNoteLevelDirty(TextureUploadTarget uploadTarget, Uint mipmapLevel);
+#endif
+
         const Uint m_externalIndex;
         const Uint64 m_lifetimeId;
         const TextureTarget m_target = TextureTarget::Unknown;

MobileGL/MG_State/GLState/TextureState/TextureObject2DCube.cpp

@@ -31,11 +31,21 @@ namespace MobileGL {
                                                       MipmapInput input) {
                 BumpShapeVersion();
                 m_textureStorage.AllocateLevel(GetIndexOfTextureUploadTarget(uploadTarget), mipmapLevel, input);
+#if MOBILEGL_PIPE_PUSH
+                // AFTER the allocation, for TextureObjectWithOneMipmap's reason: BumpShapeVersion
+                // runs first and a descriptor built there would describe the level set this call
+                // is about to change. The FACE rides in `uploadTarget`, so the key the emitter
+                // drops is that face's level and no other face's (final review C-1).
+                PipePublishLevelDescriptor(uploadTarget, mipmapLevel);
+#endif
             }
 
             void TextureObject2DCube::TruncateMipmapLevels(TextureUploadTarget uploadTarget, Uint levelCount) {
                 BumpShapeVersion();
                 m_textureStorage.TruncateToLevelCount(GetIndexOfTextureUploadTarget(uploadTarget), levelCount);
+#if MOBILEGL_PIPE_PUSH
+                PipePublishTruncatedDescriptor(uploadTarget, levelCount);
+#endif
             }
 
             void TextureObject2DCube::UpdateMipmapSubData(TextureUploadTarget uploadTarget, Uint mipmapLevel,
@@ -53,6 +63,11 @@ namespace MobileGL {
                     MGP_NOTE_AGGREGATE(TextureContent);
                 }
                 m_textureStorage.MarkDirty(GetIndexOfTextureUploadTarget(uploadTarget), mipmapLevel, dirty);
+#if MOBILEGL_PIPE_PUSH
+                // SIX FACES, SIX BLOBS, SIX DRAIN KEYS: the upload target is the face, and it is
+                // what the sub-data record's Target byte carries beside the resource target.
+                if (dirty) PipeNoteLevelDirty(uploadTarget, mipmapLevel);
+#endif
             }
 
             bool TextureObject2DCube::IsStorageDirty(TextureUploadTarget uploadTarget, Uint mipmapLevel) const {
@@ -65,6 +80,9 @@ namespace MobileGL {
                 MGP_NOTE_AGGREGATE(TextureContent);
                 m_textureStorage.MarkDirtyRegion(GetIndexOfTextureUploadTarget(uploadTarget), mipmapLevel, offset,
                                                  size);
+#if MOBILEGL_PIPE_PUSH
+                PipeNoteLevelDirty(uploadTarget, mipmapLevel);
+#endif
             }
 
             MipmapDirtyRegion TextureObject2DCube::GetStorageDirtyRegion(TextureUploadTarget uploadTarget,

MobileGL/MG_State/GLState/TextureState/TextureObjectBuffer.h

@@ -29,6 +29,15 @@ namespace MobileGL {
                 void SetBufferRange(SizeT offset, SizeT size) {
                     m_bufferRangeOffset = offset;
                     m_bufferRangeSize = size;
+#if MOBILEGL_PIPE_PUSH
+                    // Both glTexBuffer entry points bind the backing buffer and then set the
+                    // window, so this is the first statement at which the descriptor's
+                    // BufferForTexBuffer / BufOffset / BufSize trio is complete. SetInternalFormat
+                    // publishes again one statement later and is deduped away when the format did
+                    // not move - which is exactly the case a re-attach of a DIFFERENT buffer at
+                    // the same format would otherwise fall through.
+                    PipePublishDescriptor();
+#endif
                 }
                 SizeT GetBufferRangeOffset() const { return m_bufferRangeOffset; }
                 // Resolved against the buffer's current size, so kWholeBuffer tracks it.

MobileGL/MG_State/GLState/TextureState/TextureObjectView.cpp

@@ -79,6 +79,18 @@ namespace MobileGL::MG_State::GLState {
         // to the view. GetImmutableLevels() forwards to the owner for the actual GL query, which
         // GL 4.6 core 8.18 defines as the ORIGINAL texture's value.
         SetImmutableLevels(numLevels);
+#if MOBILEGL_PIPE_PUSH
+        // ViewOf, and it is published from HERE rather than left to SetImmutableLevels above,
+        // which early-returns when the composed level count happens to be the base class's
+        // current value - a degenerate view (the spec's min() composition narrowed to zero
+        // levels) would otherwise never publish the one field that makes it a view. The
+        // descriptor is deduped on its own bytes, so the ordinary case pays one compare.
+        //
+        // ONE HOP ALWAYS REACHES STORAGE: glTextureView composes a view-of-a-view onto the ROOT
+        // at creation, which is what the spec's additive min-level rule describes and what the
+        // assertion above pins, so the owner named here is never itself a view.
+        PipePublishDescriptor();
+#endif
     }
 
     Uint TextureObjectView::GetImmutableLevels() const {

MobileGL/MG_State/GLState/TextureState/TextureState.h

@@ -33,6 +33,15 @@ namespace MobileGL::MG_State::GLState {
             Access = access;
             Format = format;
             ++Version;
+#if MOBILEGL_PIPE_PUSH
+            // P4a D-A4 / final review M-A: the EARLIEST producer of kMGPipeBindShaderImage. The
+            // ImageBindableHint the bit feeds is the prevention half of the texture-remint stall
+            // class (a texture the server knows may be image-bound is allocated image-bindable
+            // up front), so it has to reach the applier before the texture's first sync - at
+            // the bind, not at the next validate point's image walk. Push-only through the
+            // contract's door, like every other hook in this directory (G1).
+            if (Texture) MG_Pipe::MGPipeNoteTextureImageBound(*Texture);
+#endif
         }
     };
 

MobileGL/MG_Test/Pipe/CMakeLists.txt

@@ -135,16 +135,25 @@ if (MSVC)
         target_compile_options(MagmaPipeIdentityTest PRIVATE /Zc:preprocessor)
 endif()
 
-# P3a's two suites. Their targets and this registration are the CONTRACT commit's, for the
-# same reason the four P2 suites' are: their CONTENTS belong to two later packages each, and
-# neither of them should have to come back to this file to add a case.
+# P3a's two suites AND P4a's six, together because they take exactly the same shape. Their
+# targets and this registration are the CONTRACT commit's, for the same reason the four P2
+# suites' are: their CONTENTS belong to two later packages each, and neither of them should
+# have to come back to this file to add a case.
+#
+# P4a's six are FramebufferEmitTest, TextureEmitTest, SamplerEmitTest, ImageEmitTest,
+# ProgramEmitTest and CompositeResolverTest. Each lands from the contract commit with one case
+# that pins the shape its later cases depend on - the emitter is one never-destroyed process
+# singleton, or the composite band has exactly one door - so none of them is an empty file
+# waiting for a package, and none of them can be registered wrongly without a red test.
 #
 # They link gtest rather than gtest_main and carry their own main(), like PipeInputsTest and
 # RenderStateSpansTest: the applier's bounds and protocol trip wires report through a log line
 # in a shipped push build and std::abort() in a poison or verify one, so a case that drives
 # one reads the line back out of a file the process names before anything logs. Deciding that
 # HERE is what keeps the later packages out of this file.
-foreach(pipeTest ResourceEmitTest VertexInputEmitTest)
+foreach(pipeTest ResourceEmitTest VertexInputEmitTest
+                 FramebufferEmitTest TextureEmitTest SamplerEmitTest ImageEmitTest
+                 ProgramEmitTest CompositeResolverTest)
         add_executable(${pipeTest} ${pipeTest}.cpp)
 
         target_include_directories(${pipeTest} PRIVATE
@@ -168,7 +177,9 @@ endforeach()
 
 include(GoogleTest)
 gtest_discover_tests(PipeCatalogueTest DISCOVERY_TIMEOUT 30 PROPERTIES LABELS unit)
-foreach(pipeTest ResourceEmitTest VertexInputEmitTest)
+foreach(pipeTest ResourceEmitTest VertexInputEmitTest
+                 FramebufferEmitTest TextureEmitTest SamplerEmitTest ImageEmitTest
+                 ProgramEmitTest CompositeResolverTest)
         gtest_discover_tests(${pipeTest} DISCOVERY_TIMEOUT 30 PROPERTIES LABELS unit)
 endforeach()
 gtest_discover_tests(MagmaPipeIdentityTest DISCOVERY_TIMEOUT 30 PROPERTIES LABELS unit)

MobileGL/MG_Test/Pipe/CompositeResolverTest.cpp

@@ -0,0 +1,786 @@
+// MobileGL - MobileGL/MG_Test/Pipe/CompositeResolverTest.cpp
+// Copyright (c) 2025-2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+
+// P4a's program-pipeline COMPOSITE: GLContext::GetProgramForDraw() already flattens a pipeline
+// into one hidden composite ProgramObject entirely in the frontend, so the client pushes ONE
+// handle for it, allocated out of the ShaderCso reserved high band, and the server never
+// learns it is a composite - it needs no "resolved draw program" hook at all.
+//
+// WHAT THIS SUITE IS ACTUALLY FOR: the composite's slot has TWO INDEPENDENT RELEASE PATHS -
+// the pipeline cache's LRU eviction and the composite ProgramObject's own destructor - and
+// both go through one client-side death helper. Either order has to free the slot exactly
+// once, and the second call has to be a proven no-op rather than a lucky one. That is what the
+// eviction-then-destruction pair and its mirror pin, and it is why the composite gets a leak
+// case of its own beside the five ordinary kinds.
+//
+// THE SUITE IS `CompositeResolver`, not `CompositeResolverTest`: the file is XTest.cpp and the
+// suite is X, this directory's convention.
+//
+// THE TARGET AND ITS ctest REGISTRATION ARE THE CONTRACT COMMIT'S; THE CONTENTS ARE NOT - the
+// resolver itself, its signature-keyed cache and the two release orders are the client
+// package's, and it never has to come back to MG_Test/Pipe/CMakeLists.txt.
+//
+// IT HAS ITS OWN main() for ResourceEmitTest's reason. Every case is a visible SKIP in a pull
+// build rather than a vanishing test, so `ctest -N` stays name-for-name identical between the
+// pull and the push trees.
+
+#include <gtest/gtest.h>
+
+#include <filesystem>
+#include <fstream>
+#include <sstream>
+#include <string>
+#include <system_error>
+
+#if defined(_WIN32)
+#include <process.h>
+#define MGTEST_HAVE_FORK 0
+#else
+#include <csignal>
+#include <sys/wait.h>
+#include <unistd.h>
+#define MGTEST_HAVE_FORK 1
+#endif
+
+#include "Includes.h"
+#include <MG_Pipe/MGPipe.h>
+#if MOBILEGL_PIPE_PUSH
+#include "Init.h"
+// MOBILEGL_PIPE_POISON is DERIVED in the header below (PipeInputs.h:20-26) and nowhere
+// else, so a TU that tests it without this include silently reads it as 0. That is
+// invisible in a push build (where it really is 0) and in a verify build (where
+// -DMOBILEGL_PIPE_VERIFY=1 is on the command line); MOBILEGL_BUILD_DISAGGREGATED is the
+// one arming condition that lives behind the header, so a split build is the first place
+// the refusals below stop being fatal while the expectations still say they are.
+#include <MG_Backend/MGPipe/PipeInputs.h>
+#include <MG_Impl/GLImpl/Program/GL_Program.h>
+#include <MG_Impl/GLImpl/Program/GL_ProgramPipeline.h>
+#include <MG_Impl/Pipe/CompositeResolver.h>
+#include <MG_Impl/Pipe/ProgramEmit.h>
+#include <MG_Impl/Pipe/SlotAllocator.h>
+#include <MG_Pipe/PipeApply.h>
+#include <MG_State/GLState/Core.h>
+// create_shader_state takes the two artefact structs by pointer beside the record, so a case
+// that mints a composite record needs their definitions.
+#include <MG_State/GLState/ProgramState/ProgramArtifacts.h>
+#endif
+
+using namespace MobileGL;
+using namespace MobileGL::MG_Pipe;
+
+namespace {
+    String g_logPath;
+
+    int ProcessId() {
+#if defined(_WIN32)
+        return _getpid();
+#else
+        return static_cast<int>(getpid());
+#endif
+    }
+
+#if MOBILEGL_PIPE_PUSH
+    // `from` is a byte offset, and it exists because of the fork below: the library's log file
+    // is already open by the time a case runs, so the child's lines are APPENDED to it rather
+    // than written to a fresh file, and only what the child appended is this drive's evidence.
+    std::string ReadLog(std::streamoff from = 0) {
+        std::ifstream in(g_logPath, std::ios::binary);
+        if (from > 0) in.seekg(from, std::ios::beg);
+        std::ostringstream ss;
+        ss << in.rdbuf();
+        return ss.str();
+    }
+
+    // Where the library's log file currently ends. Reading from here after the child has
+    // aborted gives exactly the lines that drive produced.
+    std::streamoff LogEnd() {
+        std::ifstream in(g_logPath, std::ios::binary | std::ios::ate);
+        return in ? static_cast<std::streamoff>(in.tellg()) : std::streamoff{0};
+    }
+
+    // A fresh applier per case, BOTH SCOPES, and it takes both because there are two: a reset
+    // is a make-current and deliberately KEEPS the object records, so a fixture that wants a
+    // genuinely empty applier has to say the other one as well. Every case is its own process
+    // under ctest, so this is belt and braces - but running the binary by hand must give the
+    // same answers as running it under ctest.
+    struct ApplierGuard {
+        ApplierGuard() {
+            MGPipeApplierReset();
+            MGPipeApplierReleaseObjectRecords();
+        }
+        ~ApplierGuard() {
+            MGPipeApplierReset();
+            MGPipeApplierReleaseObjectRecords();
+        }
+    };
+
+#if MGTEST_HAVE_FORK
+    struct ChildResult {
+        int Status = -1;
+        std::string Log;
+    };
+
+    template <class Body>
+    ChildResult RunInChild(Body body) {
+        ChildResult result;
+        // THE LOG PATH IS NOT UNLINKED HERE, and that is what this helper had to learn when the
+        // client's cases landed in the same file as the applier's: main() calls
+        // MobileGL::Initialize(), so the library's log FILE* is already open on this path and
+        // fork() duplicates it. Removing the path would leave the child writing into a deleted
+        // inode and the parent reading an empty file - the child would still abort, and the
+        // assertion on WHAT it named could never see the line. So the log's end is remembered
+        // and only what the child appended is read back.
+        const std::streamoff before = LogEnd();
+        std::fflush(nullptr);
+        const pid_t pid = ::fork();
+        if (pid < 0) return result;
+        if (pid == 0) {
+            body();
+            ::_exit(0);
+        }
+        int status = 0;
+        if (::waitpid(pid, &status, 0) != pid) return result;
+        result.Status = status;
+        result.Log = ReadLog(before);
+        return result;
+    }
+
+    Bool DiedOfAbort(const ChildResult& r) { return WIFSIGNALED(r.Status) && WTERMSIG(r.Status) == SIGABRT; }
+    std::string DescribeStatus(const ChildResult& r) {
+        if (r.Status < 0) return "fork/waitpid failed";
+        if (WIFEXITED(r.Status)) return "exited " + std::to_string(WEXITSTATUS(r.Status));
+        if (WIFSIGNALED(r.Status)) return "signal " + std::to_string(WTERMSIG(r.Status));
+        return "status " + std::to_string(r.Status);
+    }
+#endif // MGTEST_HAVE_FORK
+
+    // Drives a call a trip wire must REFUSE, and asserts the wire NAMED what it refused. The
+    // two arms differ by design: a poison or verify build stops the process, so the drive is a
+    // forked child and the parent reads SIGABRT plus the line out of the log; a shipped push
+    // build logs and carries on from a defined state, so there the line is read back in process
+    // and the caller goes on to assert that nothing moved.
+    template <class Body>
+    void ExpectRefusedNaming(const char* needle, Body body) {
+#if MOBILEGL_PIPE_POISON || MOBILEGL_PIPE_VERIFY
+#if MGTEST_HAVE_FORK
+        const std::string tagged = std::string("Fatal{ProtocolCorruption} ") + needle;
+        const ChildResult child = RunInChild(body);
+        EXPECT_TRUE(DiedOfAbort(child)) << DescribeStatus(child) << "; log: " << child.Log;
+        EXPECT_NE(child.Log.find(tagged), std::string::npos)
+            << "the gate fired without naming what it refused; wanted \"" << tagged << "\"; log: " << child.Log;
+#else
+        (void)needle;
+        (void)body; // no fork on this platform; the verdict here is std::abort()
+#endif
+#else
+        const std::string tagged = std::string("ProtocolCorruption ") + needle;
+        const std::string before = ReadLog();
+        body();
+        EXPECT_NE(ReadLog().substr(before.size()).find(tagged), std::string::npos)
+            << "the gate refused without saying what it refused; wanted \"" << tagged << "\"";
+#endif
+    }
+#endif // MOBILEGL_PIPE_PUSH
+} // namespace
+
+// The contract commit's one case, and it pins the property everything else in this suite is
+// built on: the composite band has EXACTLY ONE DOOR. The ordinary allocator refuses the band
+// for kind ShaderCso, AllocateComposite is the only way in, and a slot from one can never be
+// mistaken for a slot from the other - which is what reserving a band rather than setting a
+// flag on the handle buys, and what keeps the resolver's lifetime bookkeeping out of the
+// ordinary program allocator.
+TEST(CompositeResolver, TheCompositeBandHasExactlyOneDoor) {
+#if MOBILEGL_PIPE_PUSH
+    MGPipeSlotAllocator slots;
+
+    // The ordinary door never opens onto the band, however many times it is used.
+    for (int i = 0; i < 8; ++i) {
+        const MGPipeHandle ordinary = slots.Allocate(MGPipeKind::ShaderCso);
+        EXPECT_FALSE(MGPipeHandleIsNull(ordinary));
+        EXPECT_FALSE(MGPipeIsCompositeShaderSlot(ordinary.Slot));
+    }
+
+    // The composite door only ever opens onto it, and the handle it hands out is an ORDINARY
+    // ShaderCso handle in every other respect - the same kind, the same {slot, gen} rules, the
+    // same Free. The server cannot tell the difference and must not be able to.
+    const MGPipeHandle composite = slots.AllocateComposite(4242);
+    EXPECT_FALSE(MGPipeHandleIsNull(composite));
+    EXPECT_TRUE(MGPipeIsCompositeShaderSlot(composite.Slot));
+    EXPECT_TRUE(slots.IsLive(MGPipeKind::ShaderCso, composite));
+    EXPECT_EQ(slots.FindByLifetimeId(MGPipeKind::ShaderCso, 4242), composite);
+
+    // TWO RELEASE PATHS, ONE FREE. The second call resolves the same handle at a generation
+    // the slot no longer has, and Free refuses it - which is what makes "the pipeline cache
+    // evicted it and then the composite's destructor ran" safe in either order rather than a
+    // double free that only shows up as slot theft much later.
+    const Uint32 liveBefore = slots.LiveCount(MGPipeKind::ShaderCso);
+    slots.Free(MGPipeKind::ShaderCso, composite);
+    slots.Free(MGPipeKind::ShaderCso, composite);
+    EXPECT_EQ(slots.LiveCount(MGPipeKind::ShaderCso), liveBefore - 1);
+    EXPECT_FALSE(slots.IsLive(MGPipeKind::ShaderCso, composite));
+
+    // And the slot really goes back to the band rather than to the ordinary free list: the
+    // next composite reuses it with a bumped generation, and no ordinary program can be handed
+    // it.
+    const MGPipeHandle recycled = slots.AllocateComposite(4343);
+    EXPECT_EQ(recycled.Slot, composite.Slot);
+    EXPECT_NE(recycled.Gen, composite.Gen);
+    EXPECT_FALSE(MGPipeIsCompositeShaderSlot(slots.Allocate(MGPipeKind::ShaderCso).Slot));
+#else
+    GTEST_SKIP() << "MOBILEGL_PIPE_PUSH is off: there is no client slot allocator in a pull build";
+#endif
+}
+
+// =========================================================================================
+// The APPLIER's half of the composite band (the wire commits'). The client-side resolver - the
+// signature cache keyed on ComputeDrawProgramSignature, the two release paths, the eviction -
+// is the client package's and lands beside these.
+//
+// WHY THE APPLIER HAS A BAND AT ALL. It is not because the server knows what a composite is:
+// it does not, and create / bind / delete_shader_state name one exactly as they name any other
+// program. It is because the band starts at 983040, so ONE pipeline composite in a
+// slot-indexed vector would grow that vector to ~983k records of ~240 bytes each - a 236 MB
+// spike on the first pipeline draw. Both spaces stay dense against their own high-water mark.
+// =========================================================================================
+
+#if MOBILEGL_PIPE_PUSH
+namespace {
+    using MG_State::GLState::LinkArtifacts;
+    using MG_State::GLState::SpirvArtifacts;
+
+    MGPProgramDesc CompositeDesc(MGPipeHandle cso, Uint32 stageMask) {
+        MGPProgramDesc desc{};
+        desc.Cso = cso;
+        desc.StageMask = stageMask;
+        return desc;
+    }
+
+    MGPHandleOnly ProgramHandle(MGPipeHandle cso) {
+        return MGPHandleOnly{cso, static_cast<Uint32>(MGPipeKind::ShaderCso), 0};
+    }
+} // namespace
+#endif
+
+// The band's record lands in the band's own table and the ordinary one is not grown by it -
+// which is the whole 236 MB of it - and every entry point still names it as an ordinary
+// program.
+TEST(CompositeResolver, ACompositeRecordLandsInTheBandsOwnTableAndNeverGrowsTheOrdinaryOne) {
+#if !MOBILEGL_PIPE_PUSH
+    GTEST_SKIP() << "MOBILEGL_PIPE_PUSH is off: there is no applier in this build";
+#else
+    ApplierGuard guard;
+    const LinkArtifacts link;
+    const SpirvArtifacts spirv;
+    const MGPipeHandle composite{kMGPipeShaderCsoCompositeSlotBase + 2, 1};
+    ASSERT_TRUE(MGPipeIsCompositeShaderSlot(composite.Slot));
+
+    MGPipeApplyCreateShaderState(CompositeDesc(composite, 0x3u), &link, &spirv);
+    EXPECT_TRUE(MGPipeApplier().ShaderCsos.empty())
+        << "one composite grew the ordinary table to the band's base - that is the 236 MB spike";
+    ASSERT_EQ(MGPipeApplier().CompositeShaderCsos.size(), 3u)
+        << "the band's table is indexed by (slot - base) and stays dense against its own high water";
+    EXPECT_TRUE(MGPipeApplier().CompositeShaderCsos[2].Live);
+    EXPECT_EQ(MGPipeApplier().CompositeShaderCsos[2].Gen, 1u);
+    EXPECT_EQ(MGPipeApplier().CompositeShaderCsos[2].Desc.StageMask, 0x3u);
+
+    // AND THE SERVER NEVER LEARNS IT IS A COMPOSITE: the ordinary bind and draw-program calls
+    // resolve it exactly as they resolve any other program.
+    MGPipeApplyBindShaderState(ProgramHandle(composite));
+    MGPipeApplySetDrawProgram(ProgramHandle(composite));
+    EXPECT_EQ(MGPipeApplier().BoundShaderCso, composite);
+    EXPECT_EQ(MGPipeApplier().DrawProgram, composite);
+    EXPECT_EQ(MGPipeApplier().RefusedObjectCalls, 0u);
+
+    // An ordinary program lands in the other table, and the two do not see each other even
+    // though the composite's record is at index 2 of its own.
+    MGPipeApplyCreateShaderState(CompositeDesc(MGPipeHandle{2, 1}, 0x7u), &link, &spirv);
+    ASSERT_GT(MGPipeApplier().ShaderCsos.size(), 2u);
+    EXPECT_EQ(MGPipeApplier().ShaderCsos[2].Desc.StageMask, 0x7u);
+    EXPECT_EQ(MGPipeApplier().CompositeShaderCsos[2].Desc.StageMask, 0x3u)
+        << "an ordinary program at slot 2 wrote the composite at band index 2";
+#endif
+}
+
+// The composite's slot has TWO independent release paths - the pipeline cache's eviction and
+// the composite program's own destructor - and both go through one client helper. The second
+// arrival here is a refused no-op, which is what makes the double free proven rather than
+// assumed, and it clears the bindings exactly once.
+TEST(CompositeResolver, ASecondDeleteOfACompositeIsARefusedNoOpRatherThanASecondRelease) {
+#if !MOBILEGL_PIPE_PUSH
+    GTEST_SKIP() << "MOBILEGL_PIPE_PUSH is off: there is no applier in this build";
+#else
+    ApplierGuard guard;
+    const LinkArtifacts link;
+    const SpirvArtifacts spirv;
+    const MGPipeHandle composite{kMGPipeShaderCsoCompositeSlotBase, 3};
+
+    MGPipeApplyCreateShaderState(CompositeDesc(composite, 0x3u), &link, &spirv);
+    MGPipeApplySetDrawProgram(ProgramHandle(composite));
+    ASSERT_EQ(MGPipeApplier().DrawProgram, composite);
+
+    MGPipeApplyDeleteShaderState(ProgramHandle(composite));
+    EXPECT_FALSE(MGPipeApplier().CompositeShaderCsos[0].Live);
+    EXPECT_EQ(MGPipeApplier().CompositeShaderCsos[0].Gen, 3u);
+    EXPECT_TRUE(MGPipeHandleIsNull(MGPipeApplier().DrawProgram));
+    EXPECT_EQ(MGPipeApplier().RefusedObjectCalls, 0u);
+    const Uint64 serialAfterFirst = MGPipeApplier().ProgramBindingSerial;
+
+    MGPipeApplyDeleteShaderState(ProgramHandle(composite));
+    EXPECT_EQ(MGPipeApplier().RefusedObjectCalls, 1u);
+    EXPECT_EQ(MGPipeApplier().ProgramBindingSerial, serialAfterFirst)
+        << "the second release moved the binding serial, so it was not a no-op";
+
+    // And the band's slot is re-usable afterwards: a recycled composite is a new identity and
+    // starts its record over.
+    MGPipeApplyCreateShaderState(CompositeDesc(MGPipeHandle{composite.Slot, 4}, 0x1u), &link, &spirv);
+    EXPECT_TRUE(MGPipeApplier().CompositeShaderCsos[0].Live);
+    EXPECT_EQ(MGPipeApplier().CompositeShaderCsos[0].Gen, 4u);
+    EXPECT_EQ(MGPipeApplier().CompositeShaderCsos[0].Serial, 0u);
+#endif
+}
+
+// The band is INSIDE the ShaderCso slot limit, so the bound the applier refuses at is the limit
+// itself and not the band's base - a bound below it would refuse the very slots the allocator's
+// one composite door is allowed to hand out.
+TEST(CompositeResolver, ASlotAtTheShaderCsoLimitIsRefusedWhileTheLastBandSlotIsNot) {
+#if !MOBILEGL_PIPE_PUSH
+    GTEST_SKIP() << "MOBILEGL_PIPE_PUSH is off: there is no applier in this build";
+#else
+    ApplierGuard guard;
+    const LinkArtifacts link;
+    const SpirvArtifacts spirv;
+
+    // The positive control: the LAST slot of the band is a legal composite handle.
+    const MGPipeHandle last{kMGPipeShaderCsoSlotLimit - 1, 1};
+    ASSERT_TRUE(MGPipeIsCompositeShaderSlot(last.Slot));
+    MGPipeApplyCreateShaderState(CompositeDesc(last, 0x3u), &link, &spirv);
+    ASSERT_EQ(MGPipeApplier().CompositeShaderCsos.size(),
+              static_cast<SizeT>(kMGPipeShaderCsoSlotLimit - kMGPipeShaderCsoCompositeSlotBase));
+    EXPECT_TRUE(MGPipeApplier().CompositeShaderCsos.back().Live);
+    EXPECT_TRUE(MGPipeApplier().ShaderCsos.empty());
+
+    const MGPProgramDesc past = CompositeDesc(MGPipeHandle{kMGPipeShaderCsoSlotLimit, 1}, 0x3u);
+    ExpectRefusedNaming("create_shader_state {slot=1048576, gen=1}: the slot is outside the record table's "
+                        "bound",
+                        [&past, &link, &spirv]() { MGPipeApplyCreateShaderState(past, &link, &spirv); });
+
+    // And an ORDINARY slot at or above the band's base is out of range by definition: the
+    // allocator refuses the band for an ordinary program, so nothing legal can name one.
+    MGPipeApplySetDrawProgram(ProgramHandle(MGPipeHandle{kMGPipeShaderCsoCompositeSlotBase - 1, 1}));
+    EXPECT_EQ(MGPipeApplier().RefusedObjectCalls, 1u)
+        << "an ordinary slot below the band resolved against a record nobody created";
+#endif
+}
+
+#if !MOBILEGL_PIPE_PUSH
+// G2 requires the pull and push ctest name sets to be identical, name for name.
+#define MGL_COMPOSITE_RESOLVER_TEST_LIST(X)                                                        \
+    X(CompositeResolver, ACompositeIsMintedFromTheReservedBand)                                     \
+    X(CompositeResolver, ASignatureThatHasNotMovedReusesOneComposite)                               \
+    X(CompositeResolver, TwoPipelinesWithTheSameSignatureKeepTheirOwnComposite)                     \
+    X(CompositeResolver, EvictionThenDestructionFreesTheSlotExactlyOnce)                            \
+    X(CompositeResolver, DestructionThenEvictionFreesTheSlotExactlyOnce)                            \
+    X(CompositeResolver, ASignatureMoveAfterAMakeCurrentStillReleasesThroughTheResolver)         \
+    X(CompositeResolver, TwoContextsHoldingOnePipelineNameKeepTheirOwnComposites)                \
+    X(CompositeResolver, ADestroyedContextsEntryIsDroppedRatherThanReleasedASecondTime)
+
+#define MGL_DECLARE_PULL_SKIP(Suite, Name)                                                         \
+    TEST(Suite, Name) { GTEST_SKIP() << "compiled only under MOBILEGL_PIPE_PUSH"; }
+MGL_COMPOSITE_RESOLVER_TEST_LIST(MGL_DECLARE_PULL_SKIP)
+#undef MGL_DECLARE_PULL_SKIP
+#else
+
+namespace {
+    namespace GL = MobileGL::MG_Impl::GLImpl;
+    using GLContext = MG_State::GLState::GLContext;
+    using MG_State::GLState::ProgramObject;
+    using MG_State::GLState::ProgramPipelineObject;
+
+    struct ResolverScope {
+        ResolverScope() { Clear(); }
+        ~ResolverScope() {
+            GL::BindProgramPipeline(0);
+            GL::UseProgram(0);
+            Clear();
+        }
+        ResolverScope(const ResolverScope&) = delete;
+        ResolverScope& operator=(const ResolverScope&) = delete;
+
+        static void Clear() {
+            MGPipeProgramEmitterInstance().Reset();
+            MGPipeProgramEmitterInstance().ResetCounters();
+            MGPipeCompositeResolverInstance().ResetCounters();
+        }
+    };
+
+    GLContext& Ctx() { return *MG_State::pGLContext; }
+
+    const char* kVs = R"(#version 430 core
+out gl_PerVertex { vec4 gl_Position; };
+void main() { gl_Position = vec4(0.0, 0.0, 0.0, 1.0); }
+)";
+    const char* kFs = R"(#version 430 core
+out vec4 o_color;
+void main() { o_color = vec4(1.0); }
+)";
+    // A SECOND fragment stage, so a pipeline's draw-program signature can be made to move for
+    // real: ComputeDrawProgramSignature is the per-stage {lifetimeId, GetLinkVersion()} array,
+    // and a different ProgramObject is a different lifetime id.
+    const char* kFs2 = R"(#version 430 core
+out vec4 o_color;
+void main() { o_color = vec4(0.5); }
+)";
+
+    // Built by hand rather than through glCreateShaderProgramv, for ProgramPipelineCompositeTest's
+    // reason: that entry point detaches the shader right after linking, so a relink would leave
+    // the stage program with nothing to composite from.
+    GLuint MakeSeparableProgram(GLenum stage, const char* source) {
+        const GLuint shader = GL::CreateShader(stage);
+        GL::ShaderSource(shader, 1, &source, nullptr);
+        GL::CompileShader(shader);
+        const GLuint program = GL::CreateProgram();
+        GL::ProgramParameteri(program, GL_PROGRAM_SEPARABLE, GL_TRUE);
+        GL::AttachShader(program, shader);
+        GL::LinkProgram(program);
+        GLint linked = GL_FALSE;
+        GL::GetProgramiv(program, GL_LINK_STATUS, &linked);
+        EXPECT_EQ(linked, GL_TRUE) << "separable stage program did not link";
+        return program;
+    }
+
+    GLuint MakeBoundPipeline(GLuint vs, GLuint fs) {
+        GLuint pipeline = 0;
+        GL::GenProgramPipelines(1, &pipeline);
+        GL::BindProgramPipeline(pipeline);
+        GL::UseProgramStages(pipeline, GL_VERTEX_SHADER_BIT, vs);
+        GL::UseProgramStages(pipeline, GL_FRAGMENT_SHADER_BIT, fs);
+        GL::UseProgram(0);
+        return pipeline;
+    }
+
+    TEST(CompositeResolver, ACompositeIsMintedFromTheReservedBand) {
+        ResolverScope scope;
+        const GLuint vs = MakeSeparableProgram(GL_VERTEX_SHADER, kVs);
+        const GLuint fs = MakeSeparableProgram(GL_FRAGMENT_SHADER, kFs);
+        MakeBoundPipeline(vs, fs);
+
+        const SharedPtr<ProgramObject> composite = Ctx().GetProgramForDraw();
+        ASSERT_TRUE(composite) << "the frontend has to flatten the pipeline for this to mean anything";
+        // The composite is the one ProgramObject in the system with external index 0: it is
+        // deliberately not a named program, must not answer glIsProgram and must not consume a
+        // name, and glCreateProgram never returns 0.
+        EXPECT_TRUE(MGPipeProgramIsPipelineComposite(*composite));
+        EXPECT_EQ(composite->GetExternalIndex(), 0u);
+
+        ASSERT_GT(MGPipeProgramEmitterInstance().EmitShaderState(Ctx()), 0u);
+        const MGPipeHandle cso = MGPipeProgramEmitterInstance().DrawCso();
+        ASSERT_FALSE(MGPipeHandleIsNull(cso));
+        EXPECT_TRUE(MGPipeIsCompositeShaderSlot(cso.Slot))
+            << "a composite's slot comes out of the reserved band and nowhere else";
+        // AND IT IS AN ORDINARY create_shader_state. The server never learns it is a composite.
+        EXPECT_EQ(MGPipeProgramEmitterInstance().LastProgramDesc().Cso, cso);
+        EXPECT_TRUE(MGPipeProgramEmitterInstance().RecordIsPublished(cso));
+        EXPECT_EQ(MGPipeCompositeResolverInstance().GetCounters().Mints, 1u);
+    }
+
+    TEST(CompositeResolver, ASignatureThatHasNotMovedReusesOneComposite) {
+        ResolverScope scope;
+        const GLuint vs = MakeSeparableProgram(GL_VERTEX_SHADER, kVs);
+        const GLuint fs = MakeSeparableProgram(GL_FRAGMENT_SHADER, kFs);
+        MakeBoundPipeline(vs, fs);
+
+        ASSERT_GT(MGPipeProgramEmitterInstance().EmitShaderState(Ctx()), 0u);
+        const MGPipeHandle first = MGPipeProgramEmitterInstance().DrawCso();
+        ASSERT_FALSE(MGPipeHandleIsNull(first));
+        ASSERT_EQ(MGPipeProgramEmitterInstance().CreateCount(), 1u);
+
+        // The stage set did not move, so the frontend hands back the cached composite and the
+        // resolver reuses its handle - no second identity, no second record, and nothing
+        // released. THE KEY IS ComputeDrawProgramSignature's {lifetimeId, linkVersion} array
+        // and deliberately NOT GetBackendStateVersion, which a glUniform1i to a sampler moves
+        // and which used to rebuild the composite on every draw.
+        MGPipeProgramEmitterInstance().EmitShaderState(Ctx());
+        EXPECT_EQ(MGPipeProgramEmitterInstance().DrawCso(), first);
+        EXPECT_EQ(MGPipeProgramEmitterInstance().CreateCount(), 1u);
+        EXPECT_EQ(MGPipeCompositeResolverInstance().GetCounters().Releases, 0u);
+        EXPECT_GE(MGPipeCompositeResolverInstance().GetCounters().Reuses, 1u);
+    }
+
+    // [deviation] The brief names this case "TwoPipelinesWithTheSameSignatureShareOneComposite".
+    // Sharing one HANDLE between two pipeline objects is not implementable safely and the
+    // property that is true is the opposite one, so the case is named for what it asserts.
+    //
+    // The reason is the death path: a composite is an ordinary ProgramObject with its OWN
+    // lifetime id, and the client-side death helper resolves the handle FROM that lifetime id.
+    // Two composites sharing one handle would put only one of the two ids in the allocator's
+    // map, so the first ~ProgramObject would free a slot the second still names - a premature
+    // free that reappears later as slot theft, which is the exact class this whole band exists
+    // to prevent. The frontend does not share either: each ProgramPipelineObject carries its
+    // own one-slot draw-program cache, so two pipeline objects with identical stage sets are
+    // two composites in the frontend too.
+    TEST(CompositeResolver, TwoPipelinesWithTheSameSignatureKeepTheirOwnComposite) {
+        ResolverScope scope;
+        const GLuint vs = MakeSeparableProgram(GL_VERTEX_SHADER, kVs);
+        const GLuint fs = MakeSeparableProgram(GL_FRAGMENT_SHADER, kFs);
+
+        MakeBoundPipeline(vs, fs);
+        ASSERT_GT(MGPipeProgramEmitterInstance().EmitShaderState(Ctx()), 0u);
+        const MGPipeHandle firstCso = MGPipeProgramEmitterInstance().DrawCso();
+        ASSERT_FALSE(MGPipeHandleIsNull(firstCso));
+
+        MakeBoundPipeline(vs, fs); // a SECOND pipeline object, the same stage set
+        MGPipeProgramEmitterInstance().EmitShaderState(Ctx());
+        const MGPipeHandle secondCso = MGPipeProgramEmitterInstance().DrawCso();
+        ASSERT_FALSE(MGPipeHandleIsNull(secondCso));
+
+        EXPECT_NE(firstCso, secondCso);
+        EXPECT_TRUE(MGPipeIsCompositeShaderSlot(firstCso.Slot));
+        EXPECT_TRUE(MGPipeIsCompositeShaderSlot(secondCso.Slot));
+        // Both are still resolvable, which is the property a shared handle would have broken.
+        EXPECT_TRUE(MGPipeSlots().IsLive(MGPipeKind::ShaderCso, firstCso));
+        EXPECT_TRUE(MGPipeSlots().IsLive(MGPipeKind::ShaderCso, secondCso));
+    }
+
+    // THE TWO RELEASE ORDERS, driven at the level where both of them are representable. Either
+    // order frees the slot exactly once and the second call is a PROVEN no-op, because
+    // MGPipeSlotAllocator::Free refuses a slot that is not live at that generation and bumps no
+    // generation of its own - so a double release cannot skip a generation either.
+    TEST(CompositeResolver, EvictionThenDestructionFreesTheSlotExactlyOnce) {
+        ResolverScope scope;
+        constexpr Uint64 kCompositeLifetimeId = 918273645ull;
+        const Uint32 liveBefore = MGPipeSlots().LiveCount(MGPipeKind::ShaderCso);
+        const MGPipeHandle cso = MGPipeSlots().AllocateComposite(kCompositeLifetimeId);
+        ASSERT_FALSE(MGPipeHandleIsNull(cso));
+        ASSERT_TRUE(MGPipeIsCompositeShaderSlot(cso.Slot));
+        ASSERT_EQ(MGPipeSlots().LiveCount(MGPipeKind::ShaderCso), liveBefore + 1);
+
+        // 1. the pipeline cache drops it
+        MGPipeEmitShaderCsoDestroyAndFree(kCompositeLifetimeId);
+        EXPECT_FALSE(MGPipeSlots().IsLive(MGPipeKind::ShaderCso, cso));
+        EXPECT_EQ(MGPipeSlots().LiveCount(MGPipeKind::ShaderCso), liveBefore);
+        // 2. and then ~ProgramObject runs, and finds nothing to do
+        MGPipeEmitShaderCsoDestroyAndFree(kCompositeLifetimeId);
+        EXPECT_EQ(MGPipeSlots().LiveCount(MGPipeKind::ShaderCso), liveBefore);
+    }
+
+    TEST(CompositeResolver, DestructionThenEvictionFreesTheSlotExactlyOnce) {
+        ResolverScope scope;
+        constexpr Uint64 kCompositeLifetimeId = 918273646ull;
+        const Uint32 liveBefore = MGPipeSlots().LiveCount(MGPipeKind::ShaderCso);
+        const MGPipeHandle cso = MGPipeSlots().AllocateComposite(kCompositeLifetimeId);
+        ASSERT_FALSE(MGPipeHandleIsNull(cso));
+
+        // The mirror order, and it is the one that actually happens today: the frontend's
+        // one-slot cache drops its SharedPtr as it overwrites it, so ~ProgramObject usually
+        // runs first and the resolver's release is the second, redundant path.
+        MGPipeEmitShaderCsoDestroyAndFree(kCompositeLifetimeId);
+        EXPECT_FALSE(MGPipeSlots().IsLive(MGPipeKind::ShaderCso, cso));
+        MGPipeEmitShaderCsoDestroyAndFree(kCompositeLifetimeId);
+        EXPECT_EQ(MGPipeSlots().LiveCount(MGPipeKind::ShaderCso), liveBefore);
+
+        // And the slot really came back: the next composite is handed the same slot with a
+        // bumped generation, so the stale handle can never resolve to it.
+        const MGPipeHandle recycled = MGPipeSlots().AllocateComposite(kCompositeLifetimeId + 1);
+        EXPECT_EQ(recycled.Slot, cso.Slot);
+        EXPECT_NE(recycled.Gen, cso.Gen);
+        MGPipeSlots().Free(MGPipeKind::ShaderCso, recycled);
+    }
+
+    // THE RELEASE PATH THE TWO CASES ABOVE DO NOT TOUCH. Both of them call the death helper
+    // directly, so the resolver is not in the picture at all and its own release - the
+    // pipeline-cache path, the one the header says exists precisely because "usually" is not a
+    // contract - had no case of its own. This drives it, and it drives it AFTER A
+    // MAKE-CURRENT, which is where it used to be permanently disarmed:
+    //
+    //   Reset() cleared the entry's one flag; the next Observe took the reuse branch and
+    //   returned before anything could restore it; from then on ReleaseEntry saw !Live and
+    //   returned immediately - no delete_shader_state, no Free, no counter movement - and the
+    //   old composite's handle was simply overwritten out of the resolver. Nothing leaked
+    //   today only because the frontend's one-slot pipeline cache drops the last SharedPtr on
+    //   the overwrite, which is exactly the "a client that only reacted to destructors" case
+    //   the design refuses to rely on.
+    //
+    // The release obligation now lives in its own flag and a make-current does not touch it.
+    TEST(CompositeResolver, ASignatureMoveAfterAMakeCurrentStillReleasesThroughTheResolver) {
+        ResolverScope scope;
+        const GLuint vs = MakeSeparableProgram(GL_VERTEX_SHADER, kVs);
+        const GLuint fs = MakeSeparableProgram(GL_FRAGMENT_SHADER, kFs);
+        const GLuint pipeline = MakeBoundPipeline(vs, fs);
+
+        ASSERT_GT(MGPipeProgramEmitterInstance().EmitShaderState(Ctx()), 0u);
+        const MGPipeHandle first = MGPipeProgramEmitterInstance().DrawCso();
+        ASSERT_FALSE(MGPipeHandleIsNull(first));
+        ASSERT_TRUE(MGPipeIsCompositeShaderSlot(first.Slot));
+        ASSERT_TRUE(MGPipeSlots().IsLive(MGPipeKind::ShaderCso, first));
+        ASSERT_EQ(MGPipeCompositeResolverInstance().GetCounters().Releases, 0u);
+
+        // THE MAKE-CURRENT. This is exactly what PipeFill's FreshlyPrimed arm does, and it
+        // reaches MGPipeCompositeResolver::Reset() through the program emitter's own Reset().
+        MGPipeProgramEmitterInstance().Reset();
+        // ... followed by a draw whose stage set has NOT moved, which is the reuse branch.
+        MGPipeProgramEmitterInstance().EmitShaderState(Ctx());
+        EXPECT_EQ(MGPipeProgramEmitterInstance().DrawCso(), first)
+            << "the same stage set is the same composite and the same handle";
+        EXPECT_GE(MGPipeCompositeResolverInstance().GetCounters().Reuses, 1u);
+        EXPECT_EQ(MGPipeCompositeResolverInstance().GetCounters().Releases, 0u)
+            << "a reuse releases nothing";
+
+        // NOW THE STAGE SET REALLY MOVES: a different fragment stage program is a different
+        // lifetime id, so ComputeDrawProgramSignature moves and the frontend builds a second
+        // composite. The resolver has to speak the release for the first one.
+        const GLuint fs2 = MakeSeparableProgram(GL_FRAGMENT_SHADER, kFs2);
+        GL::UseProgramStages(pipeline, GL_FRAGMENT_SHADER_BIT, fs2);
+        GL::UseProgram(0);
+
+        MGPipeProgramEmitterInstance().EmitShaderState(Ctx());
+        const MGPipeHandle second = MGPipeProgramEmitterInstance().DrawCso();
+        ASSERT_FALSE(MGPipeHandleIsNull(second));
+        EXPECT_NE(second, first) << "a moved signature is a second composite with its own handle";
+        EXPECT_EQ(MGPipeCompositeResolverInstance().GetCounters().Releases, 1u)
+            << "the resolver's own release path, spoken after a make-current";
+        EXPECT_FALSE(MGPipeSlots().IsLive(MGPipeKind::ShaderCso, first))
+            << "and the first composite's slot really went back, exactly once";
+        EXPECT_TRUE(MGPipeSlots().IsLive(MGPipeKind::ShaderCso, second));
+    }
+
+    // THE RESOLVER IS A PROCESS SINGLETON AND A PIPELINE's GL NAME IS PER CONTEXT (C2-M1).
+    // GLContext owns m_programPipelines AND its own name generator m_programPipelineNames, so
+    // name N names two different ProgramPipelineObjects in two contexts, each with its own
+    // composite and its own handle. Keyed on the name alone, the first Observe after a
+    // make-current found the OTHER context's entry: the signature matched - two composites of
+    // the same stage set have the same signature, and here two default pipelines have the same
+    // all-zero one - while the handle could not, because two composites are two ProgramObjects
+    // with two lifetime ids. So it fell into ReleaseEntry and emitted delete_shader_state for a
+    // LIVE composite, cleared its publication latch and handed its band slot back while the
+    // frontend ProgramObject was still alive.
+    //
+    // DRIVEN AT THE RESOLVER RATHER THAN THROUGH GL, because one test process has one
+    // GLContext. Everything the case supplies is what the single production call site supplies:
+    // the context id is GLContext::GetTextureContextId()'s value, the two same-named pipeline
+    // objects are what two contexts hold, and the composites are ordinary ProgramObjects at
+    // external index 0 out of the reserved band, exactly as Core.cpp builds them.
+    TEST(CompositeResolver, TwoContextsHoldingOnePipelineNameKeepTheirOwnComposites) {
+        ResolverScope scope;
+        auto& resolver = MGPipeCompositeResolverInstance();
+        const LinkArtifacts link;
+        const SpirvArtifacts spirv;
+
+        constexpr Uint kSharedPipelineName = 9u;
+        constexpr Uint64 kContextA = 0x51A00001ull;
+        constexpr Uint64 kContextB = 0x51A00002ull;
+        const ProgramPipelineObject pipelineA{kSharedPipelineName};
+        const ProgramPipelineObject pipelineB{kSharedPipelineName};
+        const SharedPtr<ProgramObject> compositeA = MakeShared<ProgramObject>(0u);
+        const SharedPtr<ProgramObject> compositeB = MakeShared<ProgramObject>(0u);
+        ASSERT_TRUE(MGPipeProgramIsPipelineComposite(*compositeA));
+        ASSERT_EQ(pipelineA.GetExternalIndex(), pipelineB.GetExternalIndex());
+
+        const MGPipeHandle handleA = MGPipeSlots().AllocateComposite(compositeA->GetLifetimeId());
+        const MGPipeHandle handleB = MGPipeSlots().AllocateComposite(compositeB->GetLifetimeId());
+        ASSERT_NE(handleA, handleB);
+        for (const MGPipeHandle handle : {handleA, handleB}) {
+            MGPipeApplyCreateShaderState(CompositeDesc(handle, 0x3u), &link, &spirv);
+            MGPipeNoteHandlePublished(MGPipeKind::ShaderCso, handle);
+        }
+        const Uint64 releasesBefore = resolver.GetCounters().Releases;
+
+        EXPECT_EQ(resolver.Observe(kContextA, pipelineA, *compositeA, handleA), handleA);
+        // THE MAKE-CURRENT, which is what PipeFill's FreshlyPrimed arm reaches through the
+        // program emitter's own Reset()...
+        MGPipeProgramEmitterInstance().Reset();
+        // ... and then context B draws with ITS pipeline of the same name.
+        EXPECT_EQ(resolver.Observe(kContextB, pipelineB, *compositeB, handleB), handleB);
+
+        EXPECT_EQ(resolver.GetCounters().Releases, releasesBefore)
+            << "the other context's entry was released - it is not this pipeline's entry";
+        EXPECT_TRUE(MGPipeSlots().IsLive(MGPipeKind::ShaderCso, handleA))
+            << "A's band slot went back while A's composite ProgramObject was still alive";
+        EXPECT_TRUE(MGPipeHandleIsPublished(MGPipeKind::ShaderCso, handleA))
+            << "delete_shader_state went out for a live composite and cleared its latch";
+        EXPECT_TRUE(MGPipeSlots().IsLive(MGPipeKind::ShaderCso, handleB));
+
+        // AND BACK TO A. Its obligation stayed owed to its own context, so the unmoved
+        // signature is a reuse of the same handle and still nothing is released.
+        const Uint64 reusesBefore = resolver.GetCounters().Reuses;
+        MGPipeProgramEmitterInstance().Reset();
+        EXPECT_EQ(resolver.Observe(kContextA, pipelineA, *compositeA, handleA), handleA);
+        EXPECT_EQ(resolver.GetCounters().Reuses, reusesBefore + 1u);
+        EXPECT_EQ(resolver.GetCounters().Releases, releasesBefore);
+    }
+
+    // WHERE A DESTROYED CONTEXT's ENTRIES ARE RELEASED, and it is not in the resolver. The
+    // context's death drops m_programPipelines, which drops the ProgramPipelineObject, which
+    // drops the composite it cached; ~ProgramObject then runs the one client-side death helper
+    // and the band slot goes back EXACTLY ONCE. The resolver speaks no second delete - the
+    // entry can never be found again, and the allocator has erased the lifetime-id mapping
+    // anyway - and the next make-current DROPS the stranded entry, which is what keeps the
+    // vector bounded now that its key carries the context.
+    TEST(CompositeResolver, ADestroyedContextsEntryIsDroppedRatherThanReleasedASecondTime) {
+        ResolverScope scope;
+        auto& resolver = MGPipeCompositeResolverInstance();
+        const LinkArtifacts link;
+        const SpirvArtifacts spirv;
+
+        constexpr Uint kPipelineName = 11u;
+        constexpr Uint64 kDoomedContext = 0x51A00003ull;
+        // ResolverScope's Clear() has already run one Reset(), so every entry standing here has
+        // a live composite slot and nothing but this case's own entry can be swept below.
+        const SizeT sizeBefore = resolver.Size();
+        const Uint32 liveBefore = MGPipeSlots().LiveCount(MGPipeKind::ShaderCso);
+
+        const ProgramPipelineObject pipeline{kPipelineName};
+        SharedPtr<ProgramObject> composite = MakeShared<ProgramObject>(0u);
+        const MGPipeHandle handle = MGPipeSlots().AllocateComposite(composite->GetLifetimeId());
+        MGPipeApplyCreateShaderState(CompositeDesc(handle, 0x3u), &link, &spirv);
+        MGPipeNoteHandlePublished(MGPipeKind::ShaderCso, handle);
+        ASSERT_EQ(resolver.Observe(kDoomedContext, pipeline, *composite, handle), handle);
+        ASSERT_EQ(resolver.Size(), sizeBefore + 1u);
+        const Uint64 releasesBefore = resolver.GetCounters().Releases;
+        const Uint64 sweepsBefore = resolver.GetCounters().Sweeps;
+
+        // THE CONTEXT DIES: the last SharedPtr to its composite goes with its pipeline.
+        composite.reset();
+        EXPECT_FALSE(MGPipeSlots().IsLive(MGPipeKind::ShaderCso, handle))
+            << "~ProgramObject is the release path for this entry and it freed the slot";
+        EXPECT_FALSE(MGPipeHandleIsPublished(MGPipeKind::ShaderCso, handle))
+            << "and it took the publication latch with the delete";
+        EXPECT_EQ(MGPipeSlots().LiveCount(MGPipeKind::ShaderCso), liveBefore) << "exactly once";
+        EXPECT_EQ(resolver.GetCounters().Releases, releasesBefore)
+            << "the resolver spoke no release of its own for it";
+
+        // THE NEXT CONTEXT's FIRST VERB. The stranded entry is dropped, not released.
+        MGPipeProgramEmitterInstance().Reset();
+        EXPECT_EQ(resolver.GetCounters().Sweeps, sweepsBefore + 1u);
+        EXPECT_EQ(resolver.GetCounters().Releases, releasesBefore)
+            << "a dropped entry emits nothing and frees nothing - the obligation was discharged";
+        EXPECT_EQ(resolver.Size(), sizeBefore)
+            << "the vector is bounded by the pairs whose composite slot is actually live";
+    }
+} // namespace
+#endif // MOBILEGL_PIPE_PUSH
+
+int main(int argc, char** argv) {
+    namespace fs = std::filesystem;
+    const fs::path path =
+        fs::temp_directory_path() / ("mobilegl-compositeresolver-test-" + std::to_string(ProcessId()) + ".log");
+    std::error_code ec;
+    fs::remove(path, ec);
+    g_logPath = path.string();
+#if defined(_WIN32)
+    _putenv_s("MOBILEGL_LOG_FILE_PATH", g_logPath.c_str());
+#else
+    setenv("MOBILEGL_LOG_FILE_PATH", g_logPath.c_str(), 1);
+#endif
+#if MOBILEGL_PIPE_PUSH
+    MobileGL::Initialize();
+#endif
+    ::testing::InitGoogleTest(&argc, argv);
+    const int rc = RUN_ALL_TESTS();
+    fs::remove(path, ec);
+    return rc;
+}

MobileGL/MG_Test/Pipe/ImageEmitTest.cpp

@@ -0,0 +1,587 @@
+// MobileGL - MobileGL/MG_Test/Pipe/ImageEmitTest.cpp
+// Copyright (c) 2025-2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+
+// P4a's third kVarTail unit set, set_shader_images. It rides the sampler family's subsystem
+// bit: one family, one A/B.
+//
+// WHAT THIS SUITE IS FOR. The image set is the one whose ContentHash has to cover more than
+// the binding: InternalFormat and Access are live glBindImageTexture state that the
+// format-less image bake keys on, so a set whose only movement is an access mode still has to
+// go out. And the zero early-out is the property an optimisation deletes by accident - it is
+// what makes every draw of every application that never binds an image pay one integer test.
+//
+// THE SUITE IS `ImageEmit`, not `ImageEmitTest`: the file is XTest.cpp and the suite is X.
+//
+// THE TARGET AND ITS ctest REGISTRATION ARE THE CONTRACT COMMIT'S; THE CONTENTS ARE NOT.
+//
+// IT HAS ITS OWN main() for ResourceEmitTest's reason. Every case is a visible SKIP in a pull
+// build rather than a vanishing test, so `ctest -N` stays name-for-name identical between the
+// pull and the push trees.
+
+#include <gtest/gtest.h>
+
+#include <filesystem>
+#include <fstream>
+#include <sstream>
+#include <string>
+#include <system_error>
+
+#if defined(_WIN32)
+#include <process.h>
+#define MGTEST_HAVE_FORK 0
+#else
+#include <csignal>
+#include <sys/wait.h>
+#include <unistd.h>
+#define MGTEST_HAVE_FORK 1
+#endif
+
+#include "Includes.h"
+#include <MG_Pipe/MGPipe.h>
+#if MOBILEGL_PIPE_PUSH
+#include "Init.h"
+// MOBILEGL_PIPE_POISON is DERIVED in the header below (PipeInputs.h:20-26) and nowhere
+// else, so a TU that tests it without this include silently reads it as 0. That is
+// invisible in a push build (where it really is 0) and in a verify build (where
+// -DMOBILEGL_PIPE_VERIFY=1 is on the command line); MOBILEGL_BUILD_DISAGGREGATED is the
+// one arming condition that lives behind the header, so a split build is the first place
+// the refusals below stop being fatal while the expectations still say they are.
+#include <MG_Backend/MGPipe/PipeInputs.h>
+#include <MG_Impl/GLImpl/Program/GL_Program.h>
+#include <MG_Impl/GLImpl/Texture/GL_Texture.h>
+#include <MG_Impl/Pipe/ImageEmit.h>
+#include <MG_Impl/Pipe/TextureEmit.h>
+#include <MG_Impl/Pipe/SetHashSuppressor.h>
+#include <MG_Impl/Pipe/SlotAllocator.h>
+#include <MG_Pipe/PipeApply.h>
+#include <MG_State/GLState/Core.h>
+#endif
+
+using namespace MobileGL;
+using namespace MobileGL::MG_Pipe;
+
+namespace {
+    String g_logPath;
+
+    int ProcessId() {
+#if defined(_WIN32)
+        return _getpid();
+#else
+        return static_cast<int>(getpid());
+#endif
+    }
+
+#if MOBILEGL_PIPE_PUSH
+    // `from` is a byte offset, and it exists because of the fork below: the library's log file
+    // is already open by the time a case runs, so the child's lines are APPENDED to it rather
+    // than written to a fresh file, and only what the child appended is this drive's evidence.
+    std::string ReadLog(std::streamoff from = 0) {
+        std::ifstream in(g_logPath, std::ios::binary);
+        if (from > 0) in.seekg(from, std::ios::beg);
+        std::ostringstream ss;
+        ss << in.rdbuf();
+        return ss.str();
+    }
+
+    // Where the library's log file currently ends. Reading from here after the child has
+    // aborted gives exactly the lines that drive produced.
+    std::streamoff LogEnd() {
+        std::ifstream in(g_logPath, std::ios::binary | std::ios::ate);
+        return in ? static_cast<std::streamoff>(in.tellg()) : std::streamoff{0};
+    }
+
+    // A fresh applier per case, BOTH SCOPES, and it takes both because there are two: a reset
+    // is a make-current and deliberately KEEPS the object records, so a fixture that wants a
+    // genuinely empty applier has to say the other one as well. Every case is its own process
+    // under ctest, so this is belt and braces - but running the binary by hand must give the
+    // same answers as running it under ctest.
+    struct ApplierGuard {
+        ApplierGuard() {
+            MGPipeApplierReset();
+            MGPipeApplierReleaseObjectRecords();
+        }
+        ~ApplierGuard() {
+            MGPipeApplierReset();
+            MGPipeApplierReleaseObjectRecords();
+        }
+    };
+
+#if MGTEST_HAVE_FORK
+    struct ChildResult {
+        int Status = -1;
+        std::string Log;
+    };
+
+    template <class Body>
+    ChildResult RunInChild(Body body) {
+        ChildResult result;
+        // THE LOG PATH IS NOT UNLINKED HERE, and that is what this helper had to learn when the
+        // client's cases landed in the same file as the applier's: main() calls
+        // MobileGL::Initialize(), so the library's log FILE* is already open on this path and
+        // fork() duplicates it. Removing the path would leave the child writing into a deleted
+        // inode and the parent reading an empty file - the child would still abort, and the
+        // assertion on WHAT it named could never see the line. So the log's end is remembered
+        // and only what the child appended is read back.
+        const std::streamoff before = LogEnd();
+        std::fflush(nullptr);
+        const pid_t pid = ::fork();
+        if (pid < 0) return result;
+        if (pid == 0) {
+            body();
+            ::_exit(0);
+        }
+        int status = 0;
+        if (::waitpid(pid, &status, 0) != pid) return result;
+        result.Status = status;
+        result.Log = ReadLog(before);
+        return result;
+    }
+
+    Bool DiedOfAbort(const ChildResult& r) { return WIFSIGNALED(r.Status) && WTERMSIG(r.Status) == SIGABRT; }
+    std::string DescribeStatus(const ChildResult& r) {
+        if (r.Status < 0) return "fork/waitpid failed";
+        if (WIFEXITED(r.Status)) return "exited " + std::to_string(WEXITSTATUS(r.Status));
+        if (WIFSIGNALED(r.Status)) return "signal " + std::to_string(WTERMSIG(r.Status));
+        return "status " + std::to_string(r.Status);
+    }
+#endif // MGTEST_HAVE_FORK
+
+    // Drives a call a trip wire must REFUSE, and asserts the wire NAMED what it refused. The
+    // two arms differ by design: a poison or verify build stops the process, so the drive is a
+    // forked child and the parent reads SIGABRT plus the line out of the log; a shipped push
+    // build logs and carries on from a defined state, so there the line is read back in process
+    // and the caller goes on to assert that nothing moved.
+    template <class Body>
+    void ExpectRefusedNaming(const char* needle, Body body) {
+#if MOBILEGL_PIPE_POISON || MOBILEGL_PIPE_VERIFY
+#if MGTEST_HAVE_FORK
+        const std::string tagged = std::string("Fatal{ProtocolCorruption} ") + needle;
+        const ChildResult child = RunInChild(body);
+        EXPECT_TRUE(DiedOfAbort(child)) << DescribeStatus(child) << "; log: " << child.Log;
+        EXPECT_NE(child.Log.find(tagged), std::string::npos)
+            << "the gate fired without naming what it refused; wanted \"" << tagged << "\"; log: " << child.Log;
+#else
+        (void)needle;
+        (void)body; // no fork on this platform; the verdict here is std::abort()
+#endif
+#else
+        const std::string tagged = std::string("ProtocolCorruption ") + needle;
+        const std::string before = ReadLog();
+        body();
+        EXPECT_NE(ReadLog().substr(before.size()).find(tagged), std::string::npos)
+            << "the gate refused without saying what it refused; wanted \"" << tagged << "\"";
+#endif
+    }
+#endif // MOBILEGL_PIPE_PUSH
+} // namespace
+
+// See FramebufferEmitTest's twin for why this is a shape pin rather than a placeholder.
+TEST(ImageEmit, TheEmitterIsOneNeverDestroyedProcessSingleton) {
+#if MOBILEGL_PIPE_PUSH
+    EXPECT_EQ(&MGPipeImageEmitterInstance(), &MGPipeImageEmitterInstance());
+    // The image set has no bit of its own: set_shader_images rides the SAMPLER subsystem,
+    // because the three unit sets are one family and an operator switching them off has to get
+    // the whole family's legacy arm.
+    EXPECT_EQ(kMGPipeMaxImageUnits, kMGPipeMaxTextureUnits);
+#else
+    GTEST_SKIP() << "MOBILEGL_PIPE_PUSH is off: there is no client emitter in a pull build";
+#endif
+}
+
+// =========================================================================================
+// The APPLIER's half of set_shader_images (the wire commits'). The emitter's half - the
+// high-water-zero early-out, the content hash covering Access and InternalFormat, the shutter
+// keyed on the FRONTEND sampling-resolution generation - is the client package's.
+// =========================================================================================
+
+#if MOBILEGL_PIPE_PUSH
+namespace {
+    // Every field carries a value of its own, and two of them are the point: InternalFormat and
+    // Access are live glBindImageTexture state that the format-less image bake keys on, so a
+    // body that dropped either would leave the server baking against a format the shader was
+    // not built for.
+    MGPImageView ImageAt(Uint32 unit, Uint32 internalFormat, Uint8 access) {
+        MGPImageView view{};
+        view.Res = MGPipeHandle{unit + 1, 1};
+        view.Unit = unit;
+        view.InternalFormat = internalFormat;
+        view.Layer = 3;
+        view.Level = 2;
+        view.Layered = 1;
+        view.Access = access;
+        return view;
+    }
+} // namespace
+#endif
+
+// The window rule, one field at a time: the entries land where the header says and nowhere
+// else, and every field of an entry survives. Deleting the copy loop, the two window
+// assignments or the serial bump leaves this red.
+TEST(ImageEmit, TheImageSetLandsInItsWindowWithEveryFieldTheShaderWasBuiltAgainst) {
+#if !MOBILEGL_PIPE_PUSH
+    GTEST_SKIP() << "MOBILEGL_PIPE_PUSH is off: there is no applier in this build";
+#else
+    ApplierGuard guard;
+    // Access is a Uint8 on the wire - the client's own read/write/read-write encoding, not a
+    // GL enum - and InternalFormat is the application's, which the server recasts.
+    const MGPImageView entries[2] = {ImageAt(2, 0x8814u /* GL_RGBA32F */, 2 /* write only */),
+                                     ImageAt(3, 0x8230u /* GL_RG32F */, 3 /* read write */)};
+    MGPShaderImages header{};
+    header.Start = 2;
+    header.Count = 2;
+    header.ContentHash = 0x5150u;
+    const Uint64 serialBefore = MGPipeApplier().ShaderImagesSerial;
+    // The other two sets' serials, taken AFTER the fixture: a reset and a teardown each advance
+    // every working serial, so "unchanged" is measured from here rather than from zero.
+    const Uint64 samplerViewsSerial = MGPipeApplier().SamplerViewsSerial;
+
+    MGPipeApplySetShaderImages(header, entries);
+
+    EXPECT_EQ(MGPipeApplier().ShaderImageStart, 2u);
+    EXPECT_EQ(MGPipeApplier().ShaderImageCount, 2u);
+    EXPECT_EQ(MGPipeApplier().BoundShaderImages[2].Res, (MGPipeHandle{3, 1}));
+    EXPECT_EQ(MGPipeApplier().BoundShaderImages[2].InternalFormat, 0x8814u);
+    EXPECT_EQ(MGPipeApplier().BoundShaderImages[2].Access, 2u);
+    EXPECT_EQ(MGPipeApplier().BoundShaderImages[3].Access, 3u);
+    EXPECT_EQ(MGPipeApplier().BoundShaderImages[2].Level, 2u);
+    EXPECT_EQ(MGPipeApplier().BoundShaderImages[2].Layer, 3u);
+    EXPECT_EQ(MGPipeApplier().BoundShaderImages[2].Layered, 1u);
+    EXPECT_EQ(MGPipeApplier().BoundShaderImages[3].InternalFormat, 0x8230u);
+    EXPECT_TRUE(MGPipeHandleIsNull(MGPipeApplier().BoundShaderImages[1].Res)) << "the set wrote below its window";
+    EXPECT_TRUE(MGPipeHandleIsNull(MGPipeApplier().BoundShaderImages[4].Res)) << "the set wrote above its window";
+    EXPECT_GT(MGPipeApplier().ShaderImagesSerial, serialBefore);
+
+    // "The last set as received": a narrower set says nothing about what it does not name.
+    MGPShaderImages narrow{};
+    narrow.Start = 2;
+    narrow.Count = 1;
+    MGPipeApplySetShaderImages(narrow, entries);
+    EXPECT_EQ(MGPipeApplier().ShaderImageCount, 1u);
+    EXPECT_EQ(MGPipeApplier().BoundShaderImages[3].InternalFormat, 0x8230u)
+        << "the entry outside the new window was cleared";
+    EXPECT_EQ(MGPipeApplier().SamplerViewsSerial, samplerViewsSerial)
+        << "the image set moved another set's serial; the three are independent";
+#endif
+}
+
+// The window gate, at the bound and one past it, and the null-tail arm. The image-unit space
+// is the same merged 192 the sampler units are.
+TEST(ImageEmit, AnImageWindowPastTheImageUnitSpaceIsRefusedRatherThanTruncated) {
+#if !MOBILEGL_PIPE_PUSH
+    GTEST_SKIP() << "MOBILEGL_PIPE_PUSH is off: there is no applier in this build";
+#else
+    ApplierGuard guard;
+    const MGPImageView entry = ImageAt(0, 0x8058u, 2);
+
+    MGPShaderImages exact{};
+    exact.Start = kMGPipeMaxImageUnits - 1;
+    exact.Count = 1;
+    MGPipeApplySetShaderImages(exact, &entry);
+    ASSERT_EQ(MGPipeApplier().ShaderImageCount, 1u);
+    const Uint64 serialBefore = MGPipeApplier().ShaderImagesSerial;
+
+    MGPShaderImages past{};
+    past.Start = kMGPipeMaxImageUnits;
+    past.Count = 1;
+    past.ContentHash = 9;
+    ExpectRefusedNaming("set_shader_images {start=192, count=1, hash=9}: the window runs past the merged "
+                        "texture-unit space",
+                        [&past, &entry]() { MGPipeApplySetShaderImages(past, &entry); });
+
+    MGPShaderImages noTail{};
+    noTail.Start = 0;
+    noTail.Count = 1;
+    ExpectRefusedNaming("set_shader_images {start=0, count=1, hash=0}: a non-empty set carries no entries",
+                        [&noTail]() { MGPipeApplySetShaderImages(noTail, nullptr); });
+
+    EXPECT_EQ(MGPipeApplier().ShaderImagesSerial, serialBefore) << "a refused set moved the serial";
+    EXPECT_EQ(MGPipeApplier().ShaderImageStart, kMGPipeMaxImageUnits - 1);
+#endif
+}
+
+// An EMPTY set is not a refusal: it is what a program with no image uniforms publishes, and it
+// still moves the serial, because "no images" is a state the twin has to hear about.
+TEST(ImageEmit, AnEmptySetIsAppliedRatherThanRefusedAndStillMovesTheSerial) {
+#if !MOBILEGL_PIPE_PUSH
+    GTEST_SKIP() << "MOBILEGL_PIPE_PUSH is off: there is no applier in this build";
+#else
+    ApplierGuard guard;
+    const MGPImageView entry = ImageAt(0, 0x8058u, 1);
+    MGPShaderImages filled{};
+    filled.Count = 1;
+    MGPipeApplySetShaderImages(filled, &entry);
+    const Uint64 serialBefore = MGPipeApplier().ShaderImagesSerial;
+
+    MGPShaderImages empty{};
+    MGPipeApplySetShaderImages(empty, nullptr);
+    EXPECT_EQ(MGPipeApplier().ShaderImageCount, 0u);
+    EXPECT_GT(MGPipeApplier().ShaderImagesSerial, serialBefore);
+    EXPECT_EQ(MGPipeApplier().BoundShaderImages[0].InternalFormat, 0x8058u)
+        << "an empty window cleared entries it never named";
+#endif
+}
+
+// D-J4: the image set is per-context WORKING state, so a make-current takes it and ADVANCES
+// its serial rather than restarting it.
+TEST(ImageEmit, AMakeCurrentClearsTheImageSetAndAdvancesItsSerial) {
+#if !MOBILEGL_PIPE_PUSH
+    GTEST_SKIP() << "MOBILEGL_PIPE_PUSH is off: there is no applier in this build";
+#else
+    ApplierGuard guard;
+    const MGPImageView entry = ImageAt(1, 0x8058u, 1);
+    MGPShaderImages header{};
+    header.Start = 1;
+    header.Count = 1;
+    MGPipeApplySetShaderImages(header, &entry);
+    const Uint64 serialBefore = MGPipeApplier().ShaderImagesSerial;
+
+    MGPipeApplierReset();
+
+    EXPECT_EQ(MGPipeApplier().ShaderImageCount, 0u);
+    EXPECT_EQ(MGPipeApplier().ShaderImageStart, 0u);
+    EXPECT_TRUE(MGPipeHandleIsNull(MGPipeApplier().BoundShaderImages[1].Res));
+    EXPECT_GT(MGPipeApplier().ShaderImagesSerial, serialBefore);
+#endif
+}
+
+#if !MOBILEGL_PIPE_PUSH
+// G2 requires the pull and push ctest name sets to be identical, name for name.
+#define MGL_IMAGE_EMIT_TEST_LIST(X)                                                                \
+    X(ImageEmit, AZeroHighWaterMarkEmitsNothingWithoutHashing)                                      \
+    X(ImageEmit, AnAccessModeChangeAloneStillEmitsTheSet)                                           \
+    X(ImageEmit, AnInternalFormatChangeAloneStillEmitsTheSet)                                       \
+    X(ImageEmit, TheApplicationsFormatAndAccessTravelUnrecast)                                    \
+    X(ImageEmit, AnImageBoundTextureIsMarkedShaderImageBoundAtTheBind)
+
+#define MGL_DECLARE_PULL_SKIP(Suite, Name)                                                         \
+    TEST(Suite, Name) { GTEST_SKIP() << "compiled only under MOBILEGL_PIPE_PUSH"; }
+MGL_IMAGE_EMIT_TEST_LIST(MGL_DECLARE_PULL_SKIP)
+#undef MGL_DECLARE_PULL_SKIP
+#else
+
+namespace {
+    namespace GL = MobileGL::MG_Impl::GLImpl;
+    using GLContext = MG_State::GLState::GLContext;
+
+    struct EmitterScope {
+        EmitterScope() { Clear(); }
+        ~EmitterScope() { Clear(); }
+        EmitterScope(const EmitterScope&) = delete;
+        EmitterScope& operator=(const EmitterScope&) = delete;
+
+        static void Clear() {
+            MGPipeImageEmitterInstance().Reset();
+            MGPipeImageEmitterInstance().ResetCounters();
+            MGPipeProgramOpaqueUnitsShared().Invalidate();
+            MGPipeSetHashSuppressorInstance().InvalidateAll();
+        }
+    };
+
+    GLContext& Ctx() { return *MG_State::pGLContext; }
+    MGPipeImageEmitter& Emitter() { return MGPipeImageEmitterInstance(); }
+
+    GLuint MakeComputeProgram(const char* source) {
+        const GLuint shader = GL::CreateShader(GL_COMPUTE_SHADER);
+        GL::ShaderSource(shader, 1, &source, nullptr);
+        GL::CompileShader(shader);
+        const GLuint program = GL::CreateProgram();
+        GL::AttachShader(program, shader);
+        GL::LinkProgram(program);
+        GLint linked = GL_FALSE;
+        GL::GetProgramiv(program, GL_LINK_STATUS, &linked);
+        EXPECT_EQ(linked, GL_TRUE) << "the compute program did not link";
+        return program;
+    }
+
+    GLuint MakeImageTexture() {
+        GLuint name = 0;
+        GL::GenTextures(1, &name);
+        GL::BindTexture(GL_TEXTURE_2D, name);
+        GL::TexStorage2D(GL_TEXTURE_2D, 1, GL_RGBA8, 4, 4);
+        return name;
+    }
+
+    // PROPERTY 1 OF D-G4, and it is the one an optimisation deletes: an application that never
+    // binds an image pays one integer test per draw, taken BEFORE any hash and before any
+    // 192-entry walk.
+    //
+    // The frontend has no image-unit high-water mark of its own - NoteUnitTouched is the
+    // TEXTURE-unit path and glBindImageTexture does not reach it - so the window is derived
+    // from the highest image unit the CURRENT PROGRAM names. A program with no image uniform
+    // names none, and the set is not emitted at all.
+    TEST(ImageEmit, AZeroHighWaterMarkEmitsNothingWithoutHashing) {
+        EmitterScope scope;
+        static const char* kNoImages = R"(#version 430 core
+layout(local_size_x = 1) in;
+layout(std430, binding = 0) buffer Out { uint value; } outBuf;
+void main() { outBuf.value = 1u; }
+)";
+        const GLuint program = MakeComputeProgram(kNoImages);
+        GL::UseProgram(program);
+
+        // A texture IS bound to an image unit. The set still does not go out, because no
+        // shader can read it - which is the whole point of deriving the window from the
+        // program rather than walking 192 units to find out.
+        const GLuint texture = MakeImageTexture();
+        GL::BindImageTexture(0, texture, 0, GL_FALSE, 0, GL_READ_ONLY, GL_RGBA8);
+
+        EXPECT_EQ(Emitter().EmitShaderImages(Ctx()), 0u);
+        EXPECT_EQ(Emitter().ImageSetCount(), 0u);
+        EXPECT_EQ(Emitter().Window(), 0u);
+        GL::UseProgram(0);
+    }
+
+    const char* kImageCompute = R"(#version 430 core
+layout(local_size_x = 1) in;
+layout(binding = 1, rgba8) uniform image2D img;
+void main() { imageStore(img, ivec2(0), vec4(1.0)); }
+)";
+
+    // The record carries the APPLICATION's format and access verbatim. The bind-format recast -
+    // a GL_RG32F bind is INVALID_VALUE on most non-core formats on Adreno - and the
+    // buffer-texture split view are SERVER-side and stay there, so a client that pre-applied
+    // either of them would be answering a driver question from the wrong side of the boundary.
+    TEST(ImageEmit, TheApplicationsFormatAndAccessTravelUnrecast) {
+        EmitterScope scope;
+        const GLuint program = MakeComputeProgram(kImageCompute);
+        GL::UseProgram(program);
+        const GLuint texture = MakeImageTexture();
+        GL::BindImageTexture(1, texture, 0, GL_FALSE, 0, GL_WRITE_ONLY, GL_RGBA8);
+
+        // THE FIXTURE HAS TO SET UP WHAT THE CASE IS ABOUT, and it is asserted rather than
+        // assumed: the window comes from the program's own image uniforms, so a shader whose
+        // image uniform did not reach the reflection would make every case below pass for the
+        // wrong reason - by emitting nothing at all.
+        const SharedPtr<MG_State::GLState::ProgramObject>& object = Ctx().GetProgramObject(program);
+        ASSERT_TRUE(object);
+        const auto& resolution = MGPipeProgramOpaqueUnitsShared().For(object.get());
+        ASSERT_EQ(resolution.MaxImageUnit, 1)
+            << "maxUniformLocation=" << object->GetMaxUniformLocation()
+            << " unit@0=" << object->GetUniformSamplerOrImageUnitIndex(0)
+            << " linked=" << object->GetLinkStatus();
+
+        // ASSERTED ON THE COUNTER, NOT ON THIS CALL'S RETURN VALUE, and the reason is worth
+        // writing down because it surprised this suite: the glBindImageTexture above ALREADY
+        // reached the validate point and emitted the set, so a direct call afterwards is
+        // correctly suppressed as unchanged. What the case is about is what went out, not who
+        // sent it.
+        Emitter().EmitShaderImages(Ctx());
+        ASSERT_GE(Emitter().ImageSetCount(), 1u);
+        ASSERT_GE(Emitter().LastShaderImages().Count, 2u);
+        const MGPImageView& view = Emitter().LastImageViews()[1];
+        EXPECT_EQ(view.Unit, 1u);
+        EXPECT_FALSE(MGPipeHandleIsNull(view.Res));
+        EXPECT_EQ(view.InternalFormat, static_cast<Uint32>(GL_RGBA8));
+        EXPECT_EQ(view.Access, 1u) << "GL_WRITE_ONLY, folded into the one byte the wire carries";
+        EXPECT_EQ(view.Level, 0u);
+        EXPECT_EQ(view.Layered, 0u);
+        EXPECT_EQ(view.Layer, 0u);
+        GL::UseProgram(0);
+    }
+
+    TEST(ImageEmit, AnAccessModeChangeAloneStillEmitsTheSet) {
+        EmitterScope scope;
+        const GLuint program = MakeComputeProgram(kImageCompute);
+        GL::UseProgram(program);
+        const GLuint texture = MakeImageTexture();
+        GL::BindImageTexture(1, texture, 0, GL_FALSE, 0, GL_READ_ONLY, GL_RGBA8);
+        Emitter().EmitShaderImages(Ctx());
+        const Uint64 before = Emitter().ImageSetCount();
+        ASSERT_GE(before, 1u);
+        ASSERT_EQ(Emitter().LastImageViews()[1].Access, 0u) << "GL_READ_ONLY";
+
+        // The same texture, the same unit, the same format - only the access mode moves. The
+        // hash has to cover it, or a shader that now writes where it used to read is bound with
+        // the previous barrier and coherence semantics.
+        GL::BindImageTexture(1, texture, 0, GL_FALSE, 0, GL_READ_WRITE, GL_RGBA8);
+        Emitter().EmitShaderImages(Ctx());
+        EXPECT_GT(Emitter().ImageSetCount(), before);
+        EXPECT_EQ(Emitter().LastImageViews()[1].Access, 2u);
+        GL::UseProgram(0);
+    }
+
+    TEST(ImageEmit, AnInternalFormatChangeAloneStillEmitsTheSet) {
+        EmitterScope scope;
+        const GLuint program = MakeComputeProgram(kImageCompute);
+        GL::UseProgram(program);
+        const GLuint texture = MakeImageTexture();
+        GL::BindImageTexture(1, texture, 0, GL_FALSE, 0, GL_READ_ONLY, GL_RGBA8);
+        Emitter().EmitShaderImages(Ctx());
+        const Uint64 before = Emitter().ImageSetCount();
+        ASSERT_GE(before, 1u);
+        ASSERT_EQ(Emitter().LastImageViews()[1].InternalFormat, static_cast<Uint32>(GL_RGBA8));
+
+        // The format the shader was built against is live glBindImageTexture state, and the
+        // format-less image bake keys on it: a set suppressed because "the binding did not
+        // move" would leave the server baking against the previous format.
+        GL::BindImageTexture(1, texture, 0, GL_FALSE, 0, GL_READ_ONLY, GL_RGBA8UI);
+        Emitter().EmitShaderImages(Ctx());
+        EXPECT_GT(Emitter().ImageSetCount(), before);
+        EXPECT_EQ(Emitter().LastImageViews()[1].InternalFormat, static_cast<Uint32>(GL_RGBA8UI));
+        GL::UseProgram(0);
+    }
+
+    // FINAL REVIEW M-A: glBindImageTexture IS THE EARLIEST PRODUCER OF kMGPipeBindShaderImage -
+    // the bit the ImageBindableHint is derived from - and the emitted image set's walk is D-A4's
+    // (any texture named in an emitted MGPImageView). The hint is the PREVENTION half of the
+    // texture-remint stall class: a texture the server knows may be image-bound is allocated
+    // image-bindable up front, so it has to arrive before the first sync, i.e. at the bind.
+    // Nothing produced the bit before the fix round.
+    TEST(ImageEmit, AnImageBoundTextureIsMarkedShaderImageBoundAtTheBind) {
+        EmitterScope scope;
+        MGPipeTextureEmitterInstance().ResetForTest();
+        const GLuint name = MakeImageTexture();
+        const auto& texture = Ctx().GetTextureObject(name);
+        ASSERT_TRUE(texture);
+        const MGPipeHandle handle = MGPipeSlots().FindByLifetimeId(MGPipeKind::Texture, texture->GetLifetimeId());
+        ASSERT_FALSE(MGPipeHandleIsNull(handle));
+        EXPECT_EQ(MGPipeTextureEmitterInstance().TextureBindMask(handle) & kMGPipeBindShaderImage, 0)
+            << "nothing has image-bound this texture yet";
+
+        GL::BindImageTexture(0, name, 0, GL_FALSE, 0, GL_READ_ONLY, GL_RGBA8);
+        EXPECT_NE(MGPipeTextureEmitterInstance().TextureBindMask(handle) & kMGPipeBindShaderImage, 0)
+            << "glBindImageTexture did not mark the texture image-bound";
+
+        static const char* kOneImage = R"(#version 430 core
+layout(local_size_x = 1) in;
+layout(binding = 0, rgba8) uniform image2D img;
+void main() { imageStore(img, ivec2(0, 0), vec4(1.0)); }
+)";
+        const GLuint program = MakeComputeProgram(kOneImage);
+        GL::UseProgram(program);
+        Emitter().EmitShaderImages(Ctx());
+        ASSERT_GE(Emitter().Window(), 1u);
+        EXPECT_TRUE(Emitter().LastImageViews()[0].Res == handle);
+        EXPECT_NE(MGPipeTextureEmitterInstance().TextureBindMask(handle) & kMGPipeBindShaderImage, 0)
+            << "the emitted image set's walk does not carry the bit either";
+        GL::UseProgram(0);
+        GL::BindImageTexture(0, 0, 0, GL_FALSE, 0, GL_READ_ONLY, GL_RGBA8);
+    }
+} // namespace
+#endif // MOBILEGL_PIPE_PUSH
+
+int main(int argc, char** argv) {
+    namespace fs = std::filesystem;
+    const fs::path path =
+        fs::temp_directory_path() / ("mobilegl-imageemit-test-" + std::to_string(ProcessId()) + ".log");
+    std::error_code ec;
+    fs::remove(path, ec);
+    g_logPath = path.string();
+#if defined(_WIN32)
+    _putenv_s("MOBILEGL_LOG_FILE_PATH", g_logPath.c_str());
+#else
+    setenv("MOBILEGL_LOG_FILE_PATH", g_logPath.c_str(), 1);
+#endif
+#if MOBILEGL_PIPE_PUSH
+    MobileGL::Initialize();
+#endif
+    ::testing::InitGoogleTest(&argc, argv);
+    const int rc = RUN_ALL_TESTS();
+    fs::remove(path, ec);
+    return rc;
+}

MobileGL/MG_Test/Pipe/PipeCatalogueTest.cpp

@@ -13,10 +13,19 @@
 #include <gtest/gtest.h>
 
 #include <cstring>
+#include <iterator>
 #include <limits>
+#include <type_traits>
 
 #include "Includes.h"
 #include <MG_Pipe/MGPipe.h>
+// P4a: MGPipeUnmigratedEmulation's declaration, and the applier's records the catalogue's size
+// pins now reach. Push-only, like the translation unit that defines them - in a pull build the
+// symbol does not exist and the one case that calls it is compiled out.
+#if MOBILEGL_PIPE_PUSH
+#include <MG_Impl/Pipe/SlotAllocator.h>
+#include <MG_Pipe/PipeApply.h>
+#endif
 
 using namespace MobileGL;
 using namespace MobileGL::MG_Pipe;
@@ -157,6 +166,239 @@ TEST(PipeCatalogue, ResidualBlockIsExactlyItsTwoValueStructsPlusPatchTail) {
     EXPECT_EQ(sizeof(MGPBindRenderState), 12u);
 }
 
+// P4a's two payload edits, which are the only two the phase makes, and both are the kind a
+// compiler catches only where somebody asked it to. MGP_ASSERT_POD already pins both sizes in
+// MGPipeTypes.h; what is pinned HERE is the SHAPE the two edits were made for, because that is
+// what a later phase would silently undo.
+TEST(PipeCatalogue, TextureParamsNameTheirBuiltinSamplerAndFramebufferStateNamesItsTarget) {
+    // 32 -> 40: the CSO handle carrying the SamplerParameters of the SamplerObject every
+    // ITextureObject owns, plus the second resync bit. Naming the CSO rather than widening
+    // this payload with a filter/wrap/border block is what keeps ONE authority for one value -
+    // duplicating SamplerParameters on the wire would give two.
+    EXPECT_EQ(sizeof(MGPTextureParams), 40u);
+    EXPECT_EQ(offsetof(MGPTextureParams, Res), 0u);
+    EXPECT_EQ(offsetof(MGPTextureParams, BuiltinSampler), 8u);
+    EXPECT_EQ(offsetof(MGPTextureParams, SamplerResync), 26u);
+    // The two resync bits are SEPARATE bytes and must stay so: ForceResync guards a swizzle
+    // override the frontend params version does not move for, SamplerResync guards an
+    // incomplete texture sampling (0,0,0,1) after a driver re-mint. Different failures,
+    // different owners, one byte each.
+    EXPECT_NE(offsetof(MGPTextureParams, ForceResync), offsetof(MGPTextureParams, SamplerResync));
+
+    // Pad0 -> Uint8 Target, and the SIZE DID NOT MOVE, which is the whole point: the record
+    // describes one framebuffer OBJECT and Target says which binding(s), if any, it also
+    // sets, and that costs a byte the struct already had. Named (ID-19) cost nothing at all -
+    // it is a fourth value of a byte that was already there, which is why the applier could
+    // be given a per-object table without a wire change.
+    EXPECT_EQ(sizeof(MGPFramebufferState), 304u);
+    EXPECT_EQ(static_cast<Uint8>(MGPipeFramebufferTarget::Draw), 0u);
+    EXPECT_EQ(static_cast<Uint8>(MGPipeFramebufferTarget::Read), 1u);
+    EXPECT_EQ(static_cast<Uint8>(MGPipeFramebufferTarget::Both), 2u);
+    // Named = 3, and it is pinned by VALUE rather than merely by existence: the applier
+    // validates a record with `Target >= Count`, so an enumerator inserted ahead of Named
+    // would silently re-point every Named record the client already emits at Draw or Read -
+    // and a Draw record for a framebuffer that is not bound is the exact corruption Named
+    // exists to prevent (a DSA clear/blit landing on an unattached driver framebuffer).
+    EXPECT_EQ(static_cast<Uint8>(MGPipeFramebufferTarget::Named), 3u);
+    // Count is the applier's refusal bound and it is 4 now, not 3: a wire that still refused
+    // 3 would drop every DSA record on the floor.
+    EXPECT_EQ(static_cast<Uint8>(MGPipeFramebufferTarget::Count), 4u);
+    // The byte must be able to hold every value, since Target is a Uint8 in the record and
+    // the enum is the only thing that says what fits.
+    EXPECT_LE(static_cast<Uint32>(MGPipeFramebufferTarget::Count), 256u);
+    EXPECT_EQ(sizeof(MGPFramebufferState::Target), 1u);
+    // The wire's colour-attachment width is ONE width, and it is the wire's rather than the
+    // driver's: a driver reporting more attachments than this is refused at bring-up, never
+    // truncated into the record.
+    EXPECT_EQ(kMGPipeMaxColorAttachments, 8u);
+    EXPECT_EQ(std::extent_v<decltype(MGPFramebufferState::Color)>, kMGPipeMaxColorAttachments);
+    EXPECT_EQ(std::extent_v<decltype(MGPFramebufferState::DrawBuffers)>, kMGPipeMaxColorAttachments);
+
+    // And the two unit bounds, which bound all three var-tail sets. One merged unit space, no
+    // stage dimension.
+    EXPECT_EQ(kMGPipeMaxTextureUnits, 192u);
+    EXPECT_EQ(kMGPipeMaxImageUnits, 192u);
+}
+
+// D-A3: the resource-target enum minted beside the field, and the property that makes it worth
+// minting - EVERY TextureTarget has a row, checked at compile time by a table with no
+// `default:` arm, so adding a target is a build break rather than a descriptor that silently
+// describes the wrong kind of storage.
+TEST(PipeCatalogue, EveryTextureTargetMapsToItsOwnResourceTarget) {
+    // The compile-time half is MGPipeEveryTextureTargetIsMapped's static_assert; this is the
+    // same walk at runtime, so the case names the offender instead of the build naming a line.
+    for (SizeT i = 0; i < static_cast<SizeT>(TextureTarget::TextureTargetCount); ++i) {
+        const auto target = static_cast<TextureTarget>(i);
+        EXPECT_NE(MGPipeResourceTargetForTextureTarget(target), kMGPipeResourceTargetUnmapped)
+            << "TextureTarget " << i << " has no MGPResourceDesc::Target row";
+        EXPECT_LT(MGPipeResourceTargetForTextureTarget(target),
+                  static_cast<Uint32>(MGPipeResourceTarget::Count));
+    }
+    // Buffer is 0 and stays 0: P3a's constant is what a zero-initialised record already says,
+    // and the narrowed ack predicate below compares against it.
+    EXPECT_EQ(static_cast<Uint32>(MGPipeResourceTarget::Buffer), 0u);
+    EXPECT_EQ(kMGPipeResourceTargetBuffer, 0u);
+    // No texture target may collide with the buffer target, or a texture descriptor would ask
+    // for a synchronous acknowledgement.
+    for (SizeT i = 0; i < static_cast<SizeT>(TextureTarget::TextureTargetCount); ++i) {
+        EXPECT_NE(MGPipeResourceTargetForTextureTarget(static_cast<TextureTarget>(i)),
+                  static_cast<Uint32>(kMGPipeResourceTargetBuffer));
+    }
+    // A rectangle texture is NOT a 2D texture on the wire. Espryt lowers both to GL_TEXTURE_2D
+    // at bind time and lowers Texture1D the same way, and Tex1D still has an enumerator of its
+    // own; folding rectangle onto Tex2D here would erase a distinction both backends switch on.
+    EXPECT_NE(MGPipeResourceTargetForTextureTarget(TextureTarget::Texture2D),
+              MGPipeResourceTargetForTextureTarget(TextureTarget::TextureRectangle));
+}
+
+// P4a, D-D3 / ID-12: MGPSubData::Target is TWO facts in one Uint16 - the low byte says which
+// KIND of storage the destination is, the high byte which cube face / upload target the level
+// belongs to - and the packing is the contract's, not each emitter's.
+//
+// The property this case exists for is the COLLISION the packing prevents.
+// TextureUploadTarget::Texture1D is 0 and the applier's buffer branch tests the WHOLE field
+// == 0, so a texture record carrying the bare upload enumerator would be indistinguishable
+// from a buffer record exactly when its owner is a 1D texture, and that texture's upload
+// would be dispatched into the buffer path. Nothing else in the tree would have said so.
+TEST(PipeCatalogue, SubDataTargetPacksAResourceTargetAndAnUploadTarget) {
+    // Both halves must fit their byte, or the encoding is not an encoding.
+    static_assert(static_cast<Uint32>(MGPipeResourceTarget::Count) <= 0x100u);
+    static_assert(static_cast<Uint32>(TextureUploadTarget::TextureUploadTargetCount) <= 0x100u);
+
+    // 0 first, and deliberately: it is the enumerator that makes the collision possible. Then
+    // the plain 2D upload, the first and last cube face, and the largest enumerator the enum
+    // has, which is what proves the byte is wide enough in practice and not just in principle.
+    const Uint32 uploadTargets[] = {
+        0u,
+        static_cast<Uint32>(TextureUploadTarget::Texture2D),
+        static_cast<Uint32>(TextureUploadTarget::CubeMapPositiveX),
+        static_cast<Uint32>(TextureUploadTarget::CubeMapNegativeZ),
+        static_cast<Uint32>(TextureUploadTarget::TextureUploadTargetCount) - 1u,
+    };
+    for (Uint32 resource = 0; resource < static_cast<Uint32>(MGPipeResourceTarget::Count);
+         ++resource) {
+        for (const Uint32 upload : uploadTargets) {
+            const Uint16 packed = MGPipePackSubDataTarget(resource, upload);
+            EXPECT_EQ(MGPipeSubDataResourceTargetOf(packed), static_cast<Uint8>(resource))
+                << "resource target " << resource << " upload target " << upload;
+            EXPECT_EQ(MGPipeSubDataUploadTargetOf(packed), static_cast<Uint8>(upload))
+                << "resource target " << resource << " upload target " << upload;
+        }
+    }
+
+    // THE BUFFER INVARIANT, at compile time in MGPipeTypes.h and again here so a failure names
+    // itself: a buffer record's Target is exactly kMGPipeResourceTargetBuffer, whole field,
+    // upload byte and all, so P3a's records are unchanged on the wire.
+    static_assert(MGPipePackSubDataTarget(kMGPipeResourceTargetBuffer, 0u) ==
+                  kMGPipeResourceTargetBuffer);
+    EXPECT_EQ(MGPipePackSubDataTarget(kMGPipeResourceTargetBuffer, 0u), kMGPipeResourceTargetBuffer);
+    EXPECT_EQ(MGPipePackSubDataTarget(kMGPipeResourceTargetBuffer,
+                                      static_cast<Uint32>(TextureUploadTarget::Texture1D)),
+              kMGPipeResourceTargetBuffer);
+    MGPSubData zeroed{};
+    EXPECT_EQ(zeroed.Target, kMGPipeResourceTargetBuffer);
+
+    // ...and the other side of it: a 1D texture's upload target IS 0, and packed it still
+    // cannot be mistaken for a buffer, because no texture's resource target is 0.
+    EXPECT_EQ(static_cast<Uint32>(TextureUploadTarget::Texture1D), 0u);
+    for (Uint32 resource = 1; resource < static_cast<Uint32>(MGPipeResourceTarget::Count);
+         ++resource) {
+        EXPECT_NE(MGPipePackSubDataTarget(resource, 0u), kMGPipeResourceTargetBuffer)
+            << "resource target " << resource << " collides with a buffer record";
+    }
+    EXPECT_NE(MGPipePackSubDataTarget(MGPipeResourceTargetForTextureTarget(TextureTarget::Texture1D),
+                                      static_cast<Uint32>(TextureUploadTarget::Texture1D)),
+              kMGPipeResourceTargetBuffer);
+
+    // What a real cube-face record reads back as, through the field rather than a local.
+    MGPSubData record{};
+    record.Target =
+        MGPipePackSubDataTarget(MGPipeResourceTargetForTextureTarget(TextureTarget::TextureCubeMap),
+                                static_cast<Uint32>(TextureUploadTarget::CubeMapNegativeY));
+    EXPECT_EQ(MGPipeSubDataResourceTargetOf(record.Target),
+              static_cast<Uint8>(MGPipeResourceTarget::TexCube));
+    EXPECT_EQ(MGPipeSubDataUploadTargetOf(record.Target),
+              static_cast<Uint8>(TextureUploadTarget::CubeMapNegativeY));
+    // Six faces share one resource target: the high byte is the only thing that tells them
+    // apart, which is why it cannot be dropped.
+    EXPECT_EQ(MGPipeSubDataResourceTargetOf(
+                  MGPipePackSubDataTarget(static_cast<Uint32>(MGPipeResourceTarget::TexCube),
+                                          static_cast<Uint32>(TextureUploadTarget::CubeMapPositiveX))),
+              MGPipeSubDataResourceTargetOf(record.Target));
+    EXPECT_NE(MGPipeSubDataUploadTargetOf(
+                  MGPipePackSubDataTarget(static_cast<Uint32>(MGPipeResourceTarget::TexCube),
+                                          static_cast<Uint32>(TextureUploadTarget::CubeMapPositiveX))),
+              MGPipeSubDataUploadTargetOf(record.Target));
+}
+
+// P4a, ID-12: the three constants MGPSurface::Kind is spelled with, the texture target the
+// record grew where its Pad0 was, and MGPTextureParams::DepthStencilMode's two numbers.
+//
+// All three were UNSTATED in the contract and were being re-invented on both sides of the
+// boundary - which is the way a wire field acquires two meanings. The values themselves are
+// unremarkable; what this case pins is that there is exactly one spelling of each.
+TEST(PipeCatalogue, SurfaceNamesItsKindItsTextureTargetAndItsDepthStencilAspect) {
+    // MGPipeKind is REUSED rather than a second three-value enum minted beside the field.
+    EXPECT_EQ(kMGPipeSurfaceKindNone, static_cast<Uint8>(MGPipeKind::None));
+    EXPECT_EQ(kMGPipeSurfaceKindTexture, static_cast<Uint8>(MGPipeKind::Texture));
+    EXPECT_EQ(kMGPipeSurfaceKindRenderbuffer, static_cast<Uint8>(MGPipeKind::Renderbuffer));
+    EXPECT_NE(kMGPipeSurfaceKindTexture, kMGPipeSurfaceKindRenderbuffer);
+    // None == 0 is load-bearing: it is what makes a zero-initialised record already BE the
+    // empty attachment point, which every emitter and every reader relies on.
+    EXPECT_EQ(kMGPipeSurfaceKindNone, 0u);
+
+    // Pad0 -> Uint16 TextureTarget. THE SIZE DID NOT MOVE - the two bytes were already there -
+    // and neither did anything in front of it.
+    EXPECT_EQ(sizeof(MGPSurface), 24u);
+    EXPECT_EQ(offsetof(MGPSurface, UploadTarget), 20u);
+    EXPECT_EQ(offsetof(MGPSurface, TextureTarget), 22u);
+    // The sentinel is TextureTarget::Unknown widened, so it is a value no real target has.
+    EXPECT_EQ(kMGPipeSurfaceNoTextureTarget, 0xFFFFu);
+    EXPECT_EQ(kMGPipeSurfaceNoTextureTarget, static_cast<Uint16>(TextureTarget::Unknown));
+    for (SizeT i = 0; i < static_cast<SizeT>(TextureTarget::TextureTargetCount); ++i) {
+        EXPECT_NE(static_cast<Uint16>(i), kMGPipeSurfaceNoTextureTarget);
+    }
+
+    // A ZEROED MGPSurface CARRIES TextureTarget 0, AND 0 IS TextureTarget::Texture1D, NOT THE
+    // SENTINEL. That is documented rather than defended, and it is why the field's contract is
+    // "consulted only when Kind == kMGPipeSurfaceKindTexture": a zeroed record is Kind == None
+    // and names no texture at all, so a reader that gates on Kind can never see the 0. A
+    // reader that does not gate would read Texture1D out of an empty attachment point.
+    MGPSurface empty{};
+    EXPECT_EQ(empty.TextureTarget, 0u);
+    EXPECT_EQ(static_cast<Uint16>(TextureTarget::Texture1D), 0u);
+    EXPECT_EQ(empty.Kind, kMGPipeSurfaceKindNone);
+    EXPECT_TRUE(MGPipeHandleIsNull(empty.Res));
+
+    // A renderbuffer point names no texture and says so with the sentinel, which is what
+    // distinguishes "not a texture" from "a 1D texture" for a reader that looks anyway.
+    MGPSurface renderbuffer{};
+    renderbuffer.Kind = kMGPipeSurfaceKindRenderbuffer;
+    renderbuffer.TextureTarget = kMGPipeSurfaceNoTextureTarget;
+    EXPECT_NE(renderbuffer.TextureTarget, static_cast<Uint16>(TextureTarget::Texture1D));
+
+    // The half a compiler cannot catch: the PipeFields.def row. MGPSurface still asserts its
+    // size whether or not the field list names TextureTarget, so a comparator blind to the
+    // field would pass a target-only divergence under MOBILEGL_PIPE_VERIFY - and the field is
+    // exactly what the four cross-object masks key on.
+    MGPSurface a{};
+    MGPSurface b{};
+    const char* field = nullptr;
+    EXPECT_TRUE(MGPipeVerify(a, b, &field));
+    a.TextureTarget = static_cast<Uint16>(TextureTarget::TextureCubeMap);
+    EXPECT_FALSE(MGPipeVerify(a, b, &field));
+    EXPECT_STREQ(field, "TextureTarget");
+
+    // DepthStencilMode: 0 = GL_DEPTH_COMPONENT, 1 = GL_STENCIL_INDEX. Depth is 0 because it is
+    // the GL initial value and a texture that never asks for the stencil aspect never emits
+    // the call, so a zeroed record has to decode to what an untouched texture already has.
+    EXPECT_EQ(kMGPipeDepthStencilModeDepth, 0u);
+    EXPECT_EQ(kMGPipeDepthStencilModeStencil, 1u);
+    EXPECT_NE(kMGPipeDepthStencilModeDepth, kMGPipeDepthStencilModeStencil);
+    MGPTextureParams params{};
+    EXPECT_EQ(params.DepthStencilMode, kMGPipeDepthStencilModeDepth);
+}
+
 // G3's opcode numbering is the wire protocol. Position in PipeCalls.def, 1-based, no holes.
 TEST(PipeCatalogue, WireOpcodesAreThePositionsInTheCatalogue) {
     EXPECT_EQ(static_cast<Uint16>(MGPWireOp::GetCaps), 1);
@@ -352,9 +594,19 @@ TEST(PipeCatalogue, FloatVectorsCompareBitwise) {
 // the struct that used to memcmp is compared member by member. P3a added the two vertex wire
 // views as a seventh and eighth non-payload entry (63 + 8), for the same reason: they are the
 // elements of create_vertex_elements' blob, and a memcmp over that blob would false-differ on
-// MGPVertexAttribWire::Pad0.
+// MGPVertexAttribWire::Pad0. P4a adds SamplerParameters as a ninth (63 + 9 = 72), and the name
+// of this case stays what it was, because a removed test name is a gate failure of its own.
+//
+// SamplerParameters IS THE SHARPEST OF THE NINE. It is 100 bytes with THREE BYTES OF TRAILING
+// PADDING (96 bytes of members plus the one-byte borderColorForm), it rides
+// MGPSamplerDesc::Parameters as a blob, and until P4a it had no field list and no verify-list
+// row at all - so the comparator fell back to comparing the blob as BYTES and could
+// false-differ on padding nobody writes. That is not a theoretical hazard for this struct:
+// the client's CSO cache confirms a hash hit with a memcmp over the same bytes, so a codec or
+// a cache that read the padding would mint a fresh CSO per call and the verify lane would
+// abort at random.
 TEST(PipeCatalogue, SixValueStructsHaveFieldLists) {
-    EXPECT_EQ(kMGPipeVerifiedPayloadCount, 71u);
+    EXPECT_EQ(kMGPipeVerifiedPayloadCount, 72u);
     static_assert(MGPipeHasFieldVerifier<RenderStateParameters>::value);
     static_assert(MGPipeHasFieldVerifier<PixelStoreParameters>::value);
     static_assert(MGPipeHasFieldVerifier<PerBufferBlendState>::value);
@@ -363,6 +615,7 @@ TEST(PipeCatalogue, SixValueStructsHaveFieldLists) {
     static_assert(MGPipeHasFieldVerifier<MGHostSpan>::value);
     static_assert(MGPipeHasFieldVerifier<MGPVertexAttribWire>::value);
     static_assert(MGPipeHasFieldVerifier<MGPVertexBindingPointWire>::value);
+    static_assert(MGPipeHasFieldVerifier<SamplerParameters>::value);
     PixelStoreParameters p{};
     PixelStoreParameters q{};
     const char* field = nullptr;
@@ -377,6 +630,38 @@ TEST(PipeCatalogue, SixValueStructsHaveFieldLists) {
     t.Offset = 8;
     EXPECT_FALSE(MGPipeVerify(s, t, &field));
     EXPECT_STREQ(field, "Offset");
+
+    // P4a's ninth, and its two halves. First: the comparator sees the members, INCLUDING
+    // borderColorForm - which is the field a backend picks glSamplerParameterIiv over fv by,
+    // and which no value comparison can infer because all three border representations are
+    // always numerically populated.
+    SamplerParameters left{};
+    SamplerParameters right{};
+    EXPECT_TRUE(MGPipeVerify(left, right, &field));
+    right.borderColorForm = BorderColorForm::Int;
+    EXPECT_FALSE(MGPipeVerify(left, right, &field));
+    EXPECT_STREQ(field, "borderColorForm");
+    right = left;
+    right.borderColorI = IntVec4{1, 0, 0, 0};
+    EXPECT_FALSE(MGPipeVerify(left, right, &field));
+    EXPECT_STREQ(field, "borderColorI");
+    right = left;
+    right.maxAnisotropy = 4.0f;
+    EXPECT_FALSE(MGPipeVerify(left, right, &field));
+    EXPECT_STREQ(field, "maxAnisotropy");
+
+    // Second, and this is the one a byte comparison gets wrong: the THREE TRAILING PADDING
+    // BYTES are not fields, so garbage in them cannot make two equal sampler states differ.
+    // Written through a byte pointer, because that is the only way to reach a byte the struct
+    // does not name.
+    static_assert(sizeof(SamplerParameters) == 100);
+    right = left;
+    auto* rightBytes = reinterpret_cast<unsigned char*>(&right);
+    for (SizeT i = sizeof(SamplerParameters) - 3; i < sizeof(SamplerParameters); ++i) {
+        rightBytes[i] = 0x5A;
+    }
+    EXPECT_TRUE(MGPipeVerify(left, right, &field))
+        << "the comparator read a padding byte: field=" << (field != nullptr ? field : "(none)");
 }
 
 // G7 pins the member list the pipeline/dynamic split is derived from.
@@ -580,6 +865,158 @@ TEST(PipeCatalogue, ResourceRespecifyAcksOnlyImmutableStorage) {
     mutableStore.Width = 64u * 1024u;
     EXPECT_FALSE(MGPipeResourceRespecifyNeedsAck(mutableStore));
 
+    // P4a: THE TWO IDIOMS THAT MADE THE PREDICATE HAVE TO NARROW. Textures travel on the same
+    // resource_respecify row as buffers, and glTexStorage* sets Immutable for a real reason -
+    // it is a descriptor fact the backend reads - so an Immutable-only predicate would have
+    // started acknowledging every immutable texture allocation the moment P4a's texture family
+    // landed. Texture allocation is already deferred to sync time in monolith (glTexImage* and
+    // glTexStorage* only mark the storage dirty, and even glRenderbufferStorage* allocates
+    // lazily inside SyncToBackend), so splitting changes no observable behaviour and this batch
+    // must not ack. glBufferStorage stays the only entry point allowed a synchronous one.
+    //
+    // This is the negative control for a future widening, in both directions: a predicate that
+    // stopped naming the buffer target would turn these two green-and-wrong.
+    MGPResourceDesc immutableTexture{};
+    immutableTexture.Immutable = 1; // glTexStorage2D
+    immutableTexture.Target =
+        static_cast<Uint8>(MGPipeResourceTargetForTextureTarget(TextureTarget::Texture2D));
+    immutableTexture.Width = 256;
+    immutableTexture.Height = 256;
+    immutableTexture.Levels = 9;
+    EXPECT_FALSE(MGPipeResourceRespecifyNeedsAck(immutableTexture));
+
+    MGPResourceDesc renderbuffer{};
+    renderbuffer.Immutable = 1; // glRenderbufferStorage: one shot, and still lazy in the backend
+    renderbuffer.Target = static_cast<Uint8>(MGPipeResourceTarget::Renderbuffer);
+    renderbuffer.Width = 1920;
+    renderbuffer.Height = 1080;
+    EXPECT_FALSE(MGPipeResourceRespecifyNeedsAck(renderbuffer));
+
+    // And the buffer half still answers true with the target spelled explicitly rather than
+    // relying on a zero-initialised record to mean "buffer".
+    MGPResourceDesc immutableBuffer{};
+    immutableBuffer.Immutable = 1;
+    immutableBuffer.Target = kMGPipeResourceTargetBuffer;
+    EXPECT_TRUE(MGPipeResourceRespecifyNeedsAck(immutableBuffer));
+
     // And the opcode did not move: a flag-word edit is not a catalogue edit.
     EXPECT_EQ(static_cast<Uint16>(MGPWireOp::ResourceRespecify), 3);
+
+    // P4a, ID-18 M4. The metadata-update rule is a PROSE contract stated beside the predicate
+    // above - it compares an incoming descriptor against the applier's stored one, which this
+    // header cannot do - so what is pinnable here is the thing that would make the prose lie:
+    // a field added to MGPResourceDesc and classified into neither list. The size is the
+    // tripwire, and the two metadata fields are named so the classification cannot be lost to
+    // a rename either.
+    EXPECT_EQ(sizeof(MGPResourceDesc), 88u);
+    EXPECT_EQ(sizeof(MGPResourceDesc::BindMask), 2u);
+    EXPECT_EQ(sizeof(MGPResourceDesc::ImageBindableHint), 1u);
+    // HasDefinedContent sits next to ImageBindableHint and is deliberately on the OTHER side
+    // of the line: glBufferData(size, NULL) at an unchanged size is an orphaning
+    // reallocation, so a record that moves only it must still clear, and must never be read
+    // as a mask change.
+    EXPECT_NE(offsetof(MGPResourceDesc, HasDefinedContent),
+              offsetof(MGPResourceDesc, ImageBindableHint));
+}
+
+// G13b, D-M: "emulation 在 split 下显式 Fatal 直到 P8" costs P4a a NAMED, GREPPABLE call site
+// per unmigrated emulation and nothing else - in monolith MGPipeUnmigratedEmulation is a no-op
+// and the emulation still runs on exactly the code path it runs on today. What this pins is
+// the LIST, because the whole value of the mechanism is that P5 and P8 edit one function
+// instead of rediscovering five call sites, and a site that quietly disappears has to be a red
+// gate rather than a surprise three phases later.
+//
+// The names are pinned here rather than counted in the backend, because the count alone cannot
+// say WHICH one was lost. The purity gate greps the count; this says what the count is of.
+TEST(PipeCatalogue, EveryUnmigratedEmulationIsNamedOnce) {
+    // Every one of these is an emulation that reads or writes CLIENT memory a split server
+    // would not have: a CPU shadow mirror, a CPU mipmap fallback, a shadow-conversion readback,
+    // and the re-dirty of already-uploaded levels that a texture re-mint performs.
+    const char* const kNames[] = {
+        "copy-image-shadow-mirror",     // the glCopyImageSubData CPU-shadow mirror
+        "generate-mipmap-storage",      // EnsureGenerateMipmapStorageAllocated
+        "generate-mipmap-cpu-fallback", // GenerateThreeChannelFloatMipmapOnCpu
+        "get-tex-image-shadow",         // GetTexImageViaShadowConversion
+        "texture-remint-pull",          // RequireImageBindableStorage's re-dirty
+    };
+    EXPECT_EQ(std::size(kNames), 5u);
+    // No duplicates: two sites sharing a name would make the grepped count and this list
+    // disagree in the one direction nobody would notice.
+    for (SizeT i = 0; i < std::size(kNames); ++i) {
+        for (SizeT j = i + 1; j < std::size(kNames); ++j) {
+            EXPECT_STRNE(kNames[i], kNames[j]);
+        }
+    }
+    // The last one is the head of the only NEW stall class the design admits, and P4a supplies
+    // exactly one of its four mitigations - prevention, through ImageBindableHint on every
+    // create and respecify. The async pull, the bounded retention and the
+    // ResourceSubDataComplete terminator are a later phase's, and P4a must not build half a
+    // terminator.
+    EXPECT_STREQ(kNames[4], "texture-remint-pull");
+#if MOBILEGL_PIPE_PUSH
+    // In monolith it really is a no-op: calling it changes nothing and returns nothing. The
+    // teeth are a split server's, and the call site is what P8 gives them to.
+    for (const char* name : kNames) MGPipeUnmigratedEmulation(name);
+#endif
+}
+
+// THE ShaderCso COMPOSITE BAND IS A SECOND SPACE, AND THE ALLOCATOR REPORTS IT SEPARATELY.
+//
+// The band's base is 983040, so a composite handle passes every bound an ordinary one does and
+// a slot-indexed table that forgets the band allocates ~983k entries for one program pipeline.
+// That is why the allocator keeps two dense tables - and it is also why the two must be
+// COUNTED apart: a high-water mark that folded them would be pinned at ~983k from the first
+// composite mint onward, and every "the high-water mark did not move over N churn rounds"
+// assertion about ORDINARY ShaderCso slots - the shape that catches a dense table that never
+// shrinks, i.e. the ~1.3 KB-per-record leak the P3a final review found - would be vacuously
+// true for the rest of the process. One merged number is one real assertion and one that
+// cannot go red; two numbers are two real assertions, which is what the per-kind leak cases
+// need.
+//
+// This case pins both halves: a leaked COMPOSITE moves the band's marks and not the ordinary
+// one, and an ordinary leak still moves the ordinary mark with a composite outstanding.
+TEST(PipeCatalogue, TheCompositeShaderBandIsCountedApartFromTheOrdinarySpace) {
+#if MOBILEGL_PIPE_PUSH
+    MGPipeSlotAllocator slots;
+
+    const Uint32 ordinaryBefore = slots.HighWater(MGPipeKind::ShaderCso);
+    EXPECT_EQ(slots.CompositeHighWater(), kMGPipeShaderCsoCompositeSlotBase)
+        << "the band's high-water mark starts at its base, so it is monotone from the first mint";
+    EXPECT_EQ(slots.CompositeLiveCount(), 0u);
+    EXPECT_EQ(slots.CompositeFreeCount(), 0u);
+
+    // A COMPOSITE MOVES THE BAND'S MARKS AND ONLY THOSE.
+    const MGPipeHandle composite = slots.AllocateComposite(9001);
+    ASSERT_FALSE(MGPipeHandleIsNull(composite));
+    ASSERT_TRUE(MGPipeIsCompositeShaderSlot(composite.Slot));
+    EXPECT_EQ(slots.HighWater(MGPipeKind::ShaderCso), ordinaryBefore)
+        << "a composite mint moved the ORDINARY high-water mark, so the ordinary space's leak "
+           "assertion is vacuous from here on";
+    EXPECT_EQ(slots.CompositeHighWater(), kMGPipeShaderCsoCompositeSlotBase + 1u);
+    EXPECT_EQ(slots.CompositeLiveCount(), 1u);
+    // A live composite IS a live ShaderCso: the merged count is deliberate and stays.
+    EXPECT_EQ(slots.LiveCount(MGPipeKind::ShaderCso), 1u);
+
+    // AND THE ORDINARY MARK STILL MOVES WITH A COMPOSITE OUTSTANDING - the half that stopped
+    // existing when one number carried both spaces.
+    const MGPipeHandle ordinary = slots.Allocate(MGPipeKind::ShaderCso);
+    ASSERT_FALSE(MGPipeHandleIsNull(ordinary));
+    EXPECT_FALSE(MGPipeIsCompositeShaderSlot(ordinary.Slot));
+    EXPECT_GT(slots.HighWater(MGPipeKind::ShaderCso), ordinaryBefore);
+    EXPECT_EQ(slots.CompositeHighWater(), kMGPipeShaderCsoCompositeSlotBase + 1u)
+        << "an ordinary mint moved the BAND's high-water mark";
+
+    // The slot goes back to the BAND's free list, and the high-water marks do not come back
+    // down - which is exactly what makes them a leak witness rather than a live count.
+    const Uint32 ordinaryHighWater = slots.HighWater(MGPipeKind::ShaderCso);
+    slots.Free(MGPipeKind::ShaderCso, composite);
+    EXPECT_EQ(slots.CompositeLiveCount(), 0u);
+    EXPECT_EQ(slots.CompositeFreeCount(), 1u);
+    EXPECT_EQ(slots.FreeCount(MGPipeKind::ShaderCso), 1u);
+    EXPECT_EQ(slots.CompositeHighWater(), kMGPipeShaderCsoCompositeSlotBase + 1u);
+    EXPECT_EQ(slots.HighWater(MGPipeKind::ShaderCso), ordinaryHighWater);
+    EXPECT_EQ(slots.LiveCount(MGPipeKind::ShaderCso), 1u);
+#else
+    GTEST_SKIP() << "MOBILEGL_PIPE_PUSH is off: there is no client slot allocator in a pull build";
+#endif
 }

MobileGL/MG_Test/Pipe/ProgramEmitTest.cpp

@@ -0,0 +1,827 @@
+// MobileGL - MobileGL/MG_Test/Pipe/ProgramEmitTest.cpp
+// Copyright (c) 2025-2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+
+// P4a's program family on the client: create/bind/delete_shader_state, set_draw_program,
+// set_dispatch_program and set_global_constants.
+//
+// THE TWO PROPERTIES THIS SUITE EXISTS FOR, and both are invisible from the emitted bytes:
+//   * THE STAGE MASK COMES FROM THE LINKED SNAPSHOT, never from the live attach list.
+//     glAttachShader and glCompileShader take effect only at the NEXT link and neither moves
+//     the link version, so a descriptor built from the attach list describes a program that
+//     does not exist yet - and it would agree with nothing, because the SPIR-V array beside it
+//     is indexed by the snapshot.
+//   * THE EMITTER JOINS AND THE TRACKER DOES NOT. Bit 6's shutter reads GetCurrentProgram()
+//     deliberately and not GetProgramForDraw(), because the tracker must not force a compile
+//     just to answer "did the shader move"; the join belongs to the emitter, which makes the
+//     same call the verb is about to make anyway.
+//
+// THE SUITE IS `ProgramEmit`, not `ProgramEmitTest`: the file is XTest.cpp and the suite is X.
+//
+// THE TARGET AND ITS ctest REGISTRATION ARE THE CONTRACT COMMIT'S; THE CONTENTS ARE NOT.
+//
+// IT HAS ITS OWN main() for ResourceEmitTest's reason. Every case is a visible SKIP in a pull
+// build rather than a vanishing test, so `ctest -N` stays name-for-name identical between the
+// pull and the push trees.
+
+#include <gtest/gtest.h>
+
+#include <filesystem>
+#include <fstream>
+#include <sstream>
+#include <string>
+#include <system_error>
+
+#if defined(_WIN32)
+#include <process.h>
+#define MGTEST_HAVE_FORK 0
+#else
+#include <csignal>
+#include <sys/wait.h>
+#include <unistd.h>
+#define MGTEST_HAVE_FORK 1
+#endif
+
+#include "Includes.h"
+#include <MG_Pipe/MGPipe.h>
+#if MOBILEGL_PIPE_PUSH
+#include "Init.h"
+// MOBILEGL_PIPE_POISON is DERIVED in the header below (PipeInputs.h:20-26) and nowhere
+// else, so a TU that tests it without this include silently reads it as 0. That is
+// invisible in a push build (where it really is 0) and in a verify build (where
+// -DMOBILEGL_PIPE_VERIFY=1 is on the command line); MOBILEGL_BUILD_DISAGGREGATED is the
+// one arming condition that lives behind the header, so a split build is the first place
+// the refusals below stop being fatal while the expectations still say they are.
+#include <MG_Backend/MGPipe/PipeInputs.h>
+#include <MG_Impl/GLImpl/Program/GL_Program.h>
+#include <MG_Impl/Pipe/ProgramEmit.h>
+#include <MG_Impl/Pipe/SlotAllocator.h>
+#include <MG_Impl/Pipe/Tracker.h>
+#include <MG_Pipe/PipeApply.h>
+// The applier takes the two artefact structs BY POINTER beside the record, so a case that
+// drives create_shader_state needs their definitions - the applier's own header deliberately
+// only forward-declares them.
+#include <MG_State/GLState/ProgramState/ProgramArtifacts.h>
+#include <MG_State/GLState/Core.h>
+#endif
+
+using namespace MobileGL;
+using namespace MobileGL::MG_Pipe;
+
+namespace {
+    String g_logPath;
+
+    int ProcessId() {
+#if defined(_WIN32)
+        return _getpid();
+#else
+        return static_cast<int>(getpid());
+#endif
+    }
+
+#if MOBILEGL_PIPE_PUSH
+    // `from` is a byte offset, and it exists because of the fork below: the library's log file
+    // is already open by the time a case runs, so the child's lines are APPENDED to it rather
+    // than written to a fresh file, and only what the child appended is this drive's evidence.
+    std::string ReadLog(std::streamoff from = 0) {
+        std::ifstream in(g_logPath, std::ios::binary);
+        if (from > 0) in.seekg(from, std::ios::beg);
+        std::ostringstream ss;
+        ss << in.rdbuf();
+        return ss.str();
+    }
+
+    // Where the library's log file currently ends. Reading from here after the child has
+    // aborted gives exactly the lines that drive produced.
+    std::streamoff LogEnd() {
+        std::ifstream in(g_logPath, std::ios::binary | std::ios::ate);
+        return in ? static_cast<std::streamoff>(in.tellg()) : std::streamoff{0};
+    }
+
+    // A fresh applier per case, BOTH SCOPES, and it takes both because there are two: a reset
+    // is a make-current and deliberately KEEPS the object records, so a fixture that wants a
+    // genuinely empty applier has to say the other one as well. Every case is its own process
+    // under ctest, so this is belt and braces - but running the binary by hand must give the
+    // same answers as running it under ctest.
+    struct ApplierGuard {
+        ApplierGuard() {
+            MGPipeApplierReset();
+            MGPipeApplierReleaseObjectRecords();
+        }
+        ~ApplierGuard() {
+            MGPipeApplierReset();
+            MGPipeApplierReleaseObjectRecords();
+        }
+    };
+
+#if MGTEST_HAVE_FORK
+    struct ChildResult {
+        int Status = -1;
+        std::string Log;
+    };
+
+    template <class Body>
+    ChildResult RunInChild(Body body) {
+        ChildResult result;
+        // THE LOG PATH IS NOT UNLINKED HERE, and that is what this helper had to learn when the
+        // client's cases landed in the same file as the applier's: main() calls
+        // MobileGL::Initialize(), so the library's log FILE* is already open on this path and
+        // fork() duplicates it. Removing the path would leave the child writing into a deleted
+        // inode and the parent reading an empty file - the child would still abort, and the
+        // assertion on WHAT it named could never see the line. So the log's end is remembered
+        // and only what the child appended is read back.
+        const std::streamoff before = LogEnd();
+        std::fflush(nullptr);
+        const pid_t pid = ::fork();
+        if (pid < 0) return result;
+        if (pid == 0) {
+            body();
+            ::_exit(0);
+        }
+        int status = 0;
+        if (::waitpid(pid, &status, 0) != pid) return result;
+        result.Status = status;
+        result.Log = ReadLog(before);
+        return result;
+    }
+
+    Bool DiedOfAbort(const ChildResult& r) { return WIFSIGNALED(r.Status) && WTERMSIG(r.Status) == SIGABRT; }
+    std::string DescribeStatus(const ChildResult& r) {
+        if (r.Status < 0) return "fork/waitpid failed";
+        if (WIFEXITED(r.Status)) return "exited " + std::to_string(WEXITSTATUS(r.Status));
+        if (WIFSIGNALED(r.Status)) return "signal " + std::to_string(WTERMSIG(r.Status));
+        return "status " + std::to_string(r.Status);
+    }
+#endif // MGTEST_HAVE_FORK
+
+    // Drives a call a trip wire must REFUSE, and asserts the wire NAMED what it refused. The
+    // two arms differ by design: a poison or verify build stops the process, so the drive is a
+    // forked child and the parent reads SIGABRT plus the line out of the log; a shipped push
+    // build logs and carries on from a defined state, so there the line is read back in process
+    // and the caller goes on to assert that nothing moved.
+    template <class Body>
+    void ExpectRefusedNaming(const char* needle, Body body) {
+#if MOBILEGL_PIPE_POISON || MOBILEGL_PIPE_VERIFY
+#if MGTEST_HAVE_FORK
+        const std::string tagged = std::string("Fatal{ProtocolCorruption} ") + needle;
+        const ChildResult child = RunInChild(body);
+        EXPECT_TRUE(DiedOfAbort(child)) << DescribeStatus(child) << "; log: " << child.Log;
+        EXPECT_NE(child.Log.find(tagged), std::string::npos)
+            << "the gate fired without naming what it refused; wanted \"" << tagged << "\"; log: " << child.Log;
+#else
+        (void)needle;
+        (void)body; // no fork on this platform; the verdict here is std::abort()
+#endif
+#else
+        const std::string tagged = std::string("ProtocolCorruption ") + needle;
+        const std::string before = ReadLog();
+        body();
+        EXPECT_NE(ReadLog().substr(before.size()).find(tagged), std::string::npos)
+            << "the gate refused without saying what it refused; wanted \"" << tagged << "\"";
+#endif
+    }
+#endif // MOBILEGL_PIPE_PUSH
+} // namespace
+
+// See FramebufferEmitTest's twin for why this is a shape pin rather than a placeholder.
+TEST(ProgramEmit, TheEmitterIsOneNeverDestroyedProcessSingleton) {
+#if MOBILEGL_PIPE_PUSH
+    EXPECT_EQ(&MGPipeProgramEmitterInstance(), &MGPipeProgramEmitterInstance());
+    EXPECT_TRUE(kMGPipeWiredProgramSubsystem == 0 ||
+                kMGPipeWiredProgramSubsystem == kMGPipeSubsystemPrograms);
+#else
+    GTEST_SKIP() << "MOBILEGL_PIPE_PUSH is off: there is no client emitter in a pull build";
+#endif
+}
+
+// =========================================================================================
+// The APPLIER's half of the program family (the wire commits'): the shader CSO record, the
+// three bindings and the default uniform block. The emitter's half - the join at the validate
+// point, the never-uploaded sentinel that must never be emitted, the composite resolver - is
+// the client package's and lands beside these.
+// =========================================================================================
+
+#if MOBILEGL_PIPE_PUSH
+namespace {
+    using MG_State::GLState::LinkArtifacts;
+    using MG_State::GLState::SpirvArtifacts;
+
+    MGPProgramDesc ProgramDesc(MGPipeHandle cso, Uint32 stageMask, Uint32 globalUboSize) {
+        MGPProgramDesc desc{};
+        desc.Cso = cso;
+        desc.StageMask = stageMask;
+        desc.GlobalUboSize = globalUboSize;
+        desc.ReservedNumSamplesOffset = 32;
+        desc.SpirvStatus = 1;
+        desc.NativeFloat64 = 1;
+        desc.PointSizeDemoted = 1;
+        desc.EnableSpirvValidation = 1;
+        // ALL SEVEN BLOB REFS ARE DECLARED WITH Size 0 - "this record does not declare its
+        // blob" - which is exactly what a monolith emission is: the artefacts ride beside the
+        // record through the two companion pointers and the codec is never called.
+        return desc;
+    }
+
+    MGPHandleOnly ProgramHandle(MGPipeHandle cso) {
+        return MGPHandleOnly{cso, static_cast<Uint32>(MGPipeKind::ShaderCso), 0};
+    }
+
+    MGPGlobalConstants GlobalConstants(MGPipeHandle cso, Uint32 version) {
+        MGPGlobalConstants record{};
+        record.ShaderCso = cso;
+        record.Version = version;
+        return record;
+    }
+
+    const MGPipeShaderCsoRecord& ProgramRecordOf(Uint32 slot) {
+        EXPECT_GT(MGPipeApplier().ShaderCsos.size(), static_cast<SizeT>(slot));
+        return MGPipeApplier().ShaderCsos[slot];
+    }
+} // namespace
+#endif
+
+// A create starts the record over and leaves Serial at 0; a RE-ISSUE on the same handle is how
+// a relink travels, and it takes the default uniform block with it - a block sized to a layout
+// that no longer exists is worse than no block, and the sentinel is the value that says
+// "nothing has been uploaded for this program".
+TEST(ProgramEmit, ACreateStoresTheDescriptorAndARelinkCountsUpAndDropsTheBlockKeyedToTheOldLayout) {
+#if !MOBILEGL_PIPE_PUSH
+    GTEST_SKIP() << "MOBILEGL_PIPE_PUSH is off: there is no applier in this build";
+#else
+    ApplierGuard guard;
+    const LinkArtifacts link;
+    const SpirvArtifacts spirv;
+    const MGPipeHandle cso{5, 2};
+    const Uint8 block[64] = {};
+
+    MGPipeApplyCreateShaderState(ProgramDesc(cso, 0x3u, 64), &link, &spirv);
+    EXPECT_TRUE(ProgramRecordOf(5).Live);
+    EXPECT_EQ(ProgramRecordOf(5).Gen, 2u);
+    EXPECT_EQ(ProgramRecordOf(5).Serial, 0u) << "a create is not a mutation";
+    EXPECT_EQ(ProgramRecordOf(5).Desc.StageMask, 0x3u);
+    EXPECT_EQ(ProgramRecordOf(5).Desc.GlobalUboSize, 64u);
+    EXPECT_EQ(ProgramRecordOf(5).Desc.ReservedNumSamplesOffset, 32u);
+    EXPECT_EQ(ProgramRecordOf(5).Desc.NativeFloat64, 1u);
+    EXPECT_EQ(ProgramRecordOf(5).GlobalConstantsVersion, ~Uint32{0})
+        << "a fresh record starts at the never-uploaded sentinel";
+
+    MGPipeApplySetGlobalConstants(GlobalConstants(cso, 7), block);
+    ASSERT_EQ(ProgramRecordOf(5).GlobalConstants.size(), 64u);
+    const Uint64 blockSerial = ProgramRecordOf(5).GlobalConstantsSerial;
+
+    // The relink.
+    MGPipeApplyCreateShaderState(ProgramDesc(cso, 0x7u, 32), &link, &spirv);
+    EXPECT_EQ(ProgramRecordOf(5).Serial, 1u);
+    EXPECT_EQ(ProgramRecordOf(5).Desc.StageMask, 0x7u);
+    EXPECT_TRUE(ProgramRecordOf(5).GlobalConstants.empty())
+        << "a block sized to the layout the relink replaced survived it";
+    EXPECT_EQ(ProgramRecordOf(5).GlobalConstantsVersion, ~Uint32{0});
+    EXPECT_GT(ProgramRecordOf(5).GlobalConstantsSerial, blockSerial)
+        << "the clearing was not announced, so a twin can still match what it uploaded before";
+
+    // A RECYCLED SLOT STARTS OVER: inheriting one field of the previous occupant is how a
+    // program at a recycled slot inherits its predecessor's reflection.
+    MGPipeApplyCreateShaderState(ProgramDesc(MGPipeHandle{5, 3}, 0x1u, 16), &link, &spirv);
+    EXPECT_EQ(ProgramRecordOf(5).Gen, 3u);
+    EXPECT_EQ(ProgramRecordOf(5).Serial, 0u) << "a recycled slot kept its predecessor's serial";
+    EXPECT_EQ(ProgramRecordOf(5).Desc.StageMask, 0x1u);
+#endif
+}
+
+// The three refusals a create can produce: no artefacts at all behind seven undeclared blobs, a
+// default uniform block no program can have, and a slot outside the record table's bound.
+TEST(ProgramEmit, ACreateWithNoArtefactsAnOversizedBlockOrACorruptSlotIsRefusedNamingTheProgram) {
+#if !MOBILEGL_PIPE_PUSH
+    GTEST_SKIP() << "MOBILEGL_PIPE_PUSH is off: there is no applier in this build";
+#else
+    ApplierGuard guard;
+    const LinkArtifacts link;
+    const SpirvArtifacts spirv;
+
+    const MGPProgramDesc desc = ProgramDesc(MGPipeHandle{4, 1}, 0x3u, 0);
+    ExpectRefusedNaming("create_shader_state {slot=4, gen=1}: the record declares no blobs and carries no "
+                        "artefacts",
+                        [&desc, &spirv]() { MGPipeApplyCreateShaderState(desc, nullptr, &spirv); });
+    ExpectRefusedNaming("create_shader_state {slot=4, gen=1}: the record declares no blobs and carries no "
+                        "artefacts",
+                        [&desc, &link]() { MGPipeApplyCreateShaderState(desc, &link, nullptr); });
+    EXPECT_TRUE(MGPipeApplier().ShaderCsos.empty());
+
+    const MGPProgramDesc huge = ProgramDesc(MGPipeHandle{4, 1}, 0x3u, kMGPipeMaxGlobalConstantsBytes + 1);
+    ExpectRefusedNaming("create_shader_state {slot=4, gen=1}: the default uniform block is larger than any "
+                        "program may declare",
+                        [&huge, &link, &spirv]() { MGPipeApplyCreateShaderState(huge, &link, &spirv); });
+    EXPECT_TRUE(MGPipeApplier().ShaderCsos.empty()) << "the table was grown by a refused record";
+
+    const MGPProgramDesc pastTheBound = ProgramDesc(MGPipeHandle{kMGPipeMaxShaderCsoSlots, 1}, 0x3u, 0);
+    ExpectRefusedNaming("create_shader_state {slot=1048576, gen=1}: the slot is outside the record table's "
+                        "bound",
+                        [&pastTheBound, &link, &spirv]() {
+                            MGPipeApplyCreateShaderState(pastTheBound, &link, &spirv);
+                        });
+    EXPECT_TRUE(MGPipeApplier().ShaderCsos.empty());
+    EXPECT_TRUE(MGPipeApplier().CompositeShaderCsos.empty());
+#endif
+}
+
+// Three bindings, one serial, and each of them follows its OWN handle: set_draw_program and
+// set_dispatch_program are two calls because the frontend has two joins. A null handle is legal
+// and means "nothing bound"; a dead one leaves the previous binding standing and is counted.
+TEST(ProgramEmit, TheThreeBindingsFollowTheirOwnHandleAndADeadOneLeavesThePreviousBindingStanding) {
+#if !MOBILEGL_PIPE_PUSH
+    GTEST_SKIP() << "MOBILEGL_PIPE_PUSH is off: there is no applier in this build";
+#else
+    ApplierGuard guard;
+    const LinkArtifacts link;
+    const SpirvArtifacts spirv;
+    const MGPipeHandle draw{2, 1};
+    const MGPipeHandle dispatch{3, 1};
+    MGPipeApplyCreateShaderState(ProgramDesc(draw, 0x3u, 0), &link, &spirv);
+    MGPipeApplyCreateShaderState(ProgramDesc(dispatch, 0x20u, 0), &link, &spirv);
+
+    const Uint64 serialBefore = MGPipeApplier().ProgramBindingSerial;
+    MGPipeApplyBindShaderState(ProgramHandle(draw));
+    MGPipeApplySetDrawProgram(ProgramHandle(draw));
+    MGPipeApplySetDispatchProgram(ProgramHandle(dispatch));
+    EXPECT_EQ(MGPipeApplier().BoundShaderCso, draw);
+    EXPECT_EQ(MGPipeApplier().DrawProgram, draw);
+    EXPECT_EQ(MGPipeApplier().DispatchProgram, dispatch);
+    EXPECT_EQ(MGPipeApplier().ProgramBindingSerial, serialBefore + 3);
+
+    // A dead handle: previous binding untouched, and COUNTED - a no-op nobody can see is a
+    // dropped bind nobody can see.
+    const Uint64 refusedBefore = MGPipeApplier().RefusedObjectCalls;
+    MGPipeApplySetDrawProgram(ProgramHandle(MGPipeHandle{2, 9}));
+    MGPipeApplyBindShaderState(ProgramHandle(MGPipeHandle{99, 1}));
+    MGPipeApplySetDispatchProgram(ProgramHandle(MGPipeHandle{3, 9}));
+    EXPECT_EQ(MGPipeApplier().RefusedObjectCalls, refusedBefore + 3);
+    EXPECT_EQ(MGPipeApplier().DrawProgram, draw);
+    EXPECT_EQ(MGPipeApplier().BoundShaderCso, draw);
+    EXPECT_EQ(MGPipeApplier().DispatchProgram, dispatch);
+    EXPECT_EQ(MGPipeApplier().ProgramBindingSerial, serialBefore + 3) << "a refused bind moved the serial";
+
+    // The null handle is a state, not an error.
+    MGPipeApplySetDrawProgram(ProgramHandle(kMGPipeNullHandle));
+    EXPECT_TRUE(MGPipeHandleIsNull(MGPipeApplier().DrawProgram));
+    EXPECT_EQ(MGPipeApplier().ProgramBindingSerial, serialBefore + 4);
+    EXPECT_EQ(MGPipeApplier().RefusedObjectCalls, refusedBefore + 3) << "a null bind was counted as a refusal";
+#endif
+}
+
+// A delete drops the record whole, keeps the generation, and clears EVERY binding that named
+// it - unlike the unit sets, which are "the last set as received". A binding left pointing at a
+// dropped record would make the next verb refuse a state the applier itself created.
+TEST(ProgramEmit, ADeleteDropsTheRecordAndClearsEveryBindingThatNamedIt) {
+#if !MOBILEGL_PIPE_PUSH
+    GTEST_SKIP() << "MOBILEGL_PIPE_PUSH is off: there is no applier in this build";
+#else
+    ApplierGuard guard;
+    const LinkArtifacts link;
+    const SpirvArtifacts spirv;
+    const MGPipeHandle cso{6, 4};
+    MGPipeApplyCreateShaderState(ProgramDesc(cso, 0x3u, 0), &link, &spirv);
+    MGPipeApplyBindShaderState(ProgramHandle(cso));
+    MGPipeApplySetDrawProgram(ProgramHandle(cso));
+    MGPipeApplySetDispatchProgram(ProgramHandle(cso));
+    const Uint64 serialBefore = MGPipeApplier().ProgramBindingSerial;
+
+    MGPipeApplyDeleteShaderState(ProgramHandle(cso));
+    EXPECT_FALSE(ProgramRecordOf(6).Live);
+    EXPECT_EQ(ProgramRecordOf(6).Gen, 4u) << "a destroy keeps the generation";
+    EXPECT_EQ(ProgramRecordOf(6).Desc.StageMask, 0u)
+        << "a stale read of a deleted slot must find nothing, not the program that used to be there";
+    EXPECT_TRUE(MGPipeHandleIsNull(MGPipeApplier().BoundShaderCso));
+    EXPECT_TRUE(MGPipeHandleIsNull(MGPipeApplier().DrawProgram));
+    EXPECT_TRUE(MGPipeHandleIsNull(MGPipeApplier().DispatchProgram));
+    EXPECT_GT(MGPipeApplier().ProgramBindingSerial, serialBefore);
+
+    // THE SECOND NOTICE IS A REFUSED NO-OP. A composite's slot has two independent release
+    // paths and both arrive here; the second finding nothing is what makes the double free
+    // proven rather than assumed.
+    const Uint64 serialAfter = MGPipeApplier().ProgramBindingSerial;
+    MGPipeApplyDeleteShaderState(ProgramHandle(cso));
+    EXPECT_EQ(MGPipeApplier().RefusedObjectCalls, 1u);
+    EXPECT_EQ(MGPipeApplier().ProgramBindingSerial, serialAfter);
+#endif
+}
+
+// The default uniform block lands on the PROGRAM's record - it is (ShaderCso, Version) keyed
+// and belongs to the program, not to the context that uploaded it - and the length it is held
+// to is the program's own GlobalUboSize, which the create already bounded.
+TEST(ProgramEmit, TheDefaultUniformBlockLandsOnTheProgramsRecordAndTheSentinelIsRefused) {
+#if !MOBILEGL_PIPE_PUSH
+    GTEST_SKIP() << "MOBILEGL_PIPE_PUSH is off: there is no applier in this build";
+#else
+    ApplierGuard guard;
+    const LinkArtifacts link;
+    const SpirvArtifacts spirv;
+    const MGPipeHandle cso{7, 1};
+    MGPipeApplyCreateShaderState(ProgramDesc(cso, 0x3u, 8), &link, &spirv);
+
+    Uint8 block[8] = {1, 2, 3, 4, 5, 6, 7, 8};
+    MGPipeApplySetGlobalConstants(GlobalConstants(cso, 11), block);
+    ASSERT_EQ(ProgramRecordOf(7).GlobalConstants.size(), 8u);
+    EXPECT_EQ(ProgramRecordOf(7).GlobalConstants[7], 8u);
+    EXPECT_EQ(ProgramRecordOf(7).GlobalConstantsVersion, 11u);
+    EXPECT_EQ(ProgramRecordOf(7).GlobalConstantsSerial, 1u);
+    EXPECT_EQ(ProgramRecordOf(7).Serial, 0u) << "a block upload is not a relink";
+
+    // A DECLARED blob length that agrees is fine; one that does not is refused, and so is the
+    // sentinel the backends read as "never uploaded".
+    MGPGlobalConstants declared = GlobalConstants(cso, 12);
+    declared.Blob.Size = 8;
+    MGPipeApplySetGlobalConstants(declared, block);
+    EXPECT_EQ(ProgramRecordOf(7).GlobalConstantsVersion, 12u);
+
+    MGPGlobalConstants lying = GlobalConstants(cso, 13);
+    lying.Blob.Size = 9;
+    ExpectRefusedNaming("set_global_constants {slot=7, gen=1}: the declared blob length is not the "
+                        "program's own default uniform block size",
+                        [&lying, &block]() { MGPipeApplySetGlobalConstants(lying, block); });
+
+    const MGPGlobalConstants sentinel = GlobalConstants(cso, ~Uint32{0});
+    ExpectRefusedNaming("set_global_constants {slot=7, gen=1}: the version is the backends' "
+                        "never-uploaded sentinel",
+                        [&sentinel, &block]() { MGPipeApplySetGlobalConstants(sentinel, block); });
+
+    const MGPGlobalConstants noBytes = GlobalConstants(cso, 14);
+    ExpectRefusedNaming("set_global_constants {slot=7, gen=1}: a non-empty block carries no bytes",
+                        [&noBytes]() { MGPipeApplySetGlobalConstants(noBytes, nullptr); });
+
+    EXPECT_EQ(ProgramRecordOf(7).GlobalConstantsVersion, 12u) << "a refused block was stored anyway";
+    EXPECT_EQ(ProgramRecordOf(7).GlobalConstantsSerial, 2u);
+
+    // And a block for a program this applier does not have is the ordinary counted refusal.
+    MGPipeApplySetGlobalConstants(GlobalConstants(MGPipeHandle{7, 2}, 15), block);
+    EXPECT_EQ(MGPipeApplier().RefusedObjectCalls, 1u);
+#endif
+}
+
+// D-J4 for this family: the program record is share-group state and survives a make-current -
+// re-emitting create_shader_state for a record the applier still holds would move its serial
+// for nothing - while the three bindings are working state and do not.
+TEST(ProgramEmit, TheProgramRecordSurvivesAMakeCurrentWhileTheThreeBindingsDoNot) {
+#if !MOBILEGL_PIPE_PUSH
+    GTEST_SKIP() << "MOBILEGL_PIPE_PUSH is off: there is no applier in this build";
+#else
+    ApplierGuard guard;
+    const LinkArtifacts link;
+    const SpirvArtifacts spirv;
+    const MGPipeHandle cso{8, 1};
+    const Uint8 block[4] = {9, 9, 9, 9};
+    MGPipeApplyCreateShaderState(ProgramDesc(cso, 0x3u, 4), &link, &spirv);
+    MGPipeApplySetGlobalConstants(GlobalConstants(cso, 21), block);
+    MGPipeApplyBindShaderState(ProgramHandle(cso));
+    MGPipeApplySetDrawProgram(ProgramHandle(cso));
+    const Uint64 bindingSerial = MGPipeApplier().ProgramBindingSerial;
+
+    MGPipeApplierReset();
+
+    ASSERT_TRUE(ProgramRecordOf(8).Live) << "a make-current dropped a share-group program record";
+    EXPECT_EQ(ProgramRecordOf(8).GlobalConstantsVersion, 21u);
+    EXPECT_EQ(ProgramRecordOf(8).GlobalConstants.size(), 4u);
+    EXPECT_TRUE(MGPipeHandleIsNull(MGPipeApplier().BoundShaderCso));
+    EXPECT_TRUE(MGPipeHandleIsNull(MGPipeApplier().DrawProgram));
+    EXPECT_GT(MGPipeApplier().ProgramBindingSerial, bindingSerial)
+        << "the binding serial was carried over or restarted rather than advanced";
+
+    // The bind that follows the switch still resolves, which is the whole point of the rule.
+    MGPipeApplySetDrawProgram(ProgramHandle(cso));
+    EXPECT_EQ(MGPipeApplier().DrawProgram, cso);
+    EXPECT_EQ(MGPipeApplier().RefusedObjectCalls, 0u);
+
+    MGPipeApplierReleaseObjectRecords();
+    EXPECT_TRUE(MGPipeApplier().ShaderCsos.empty());
+#endif
+}
+
+#if !MOBILEGL_PIPE_PUSH
+// G2 requires the pull and push ctest name sets to be identical, name for name.
+#define MGL_PROGRAM_EMIT_TEST_LIST(X)                                                              \
+    X(ProgramEmit, TheStageMaskComesFromTheLinkedSnapshotAndNotTheAttachList)                       \
+    X(ProgramEmit, TheNeverUploadedSentinelIsNeverEmitted)                                          \
+    X(ProgramEmit, TheEmitterJoinsAndTheTrackerDoesNot)                                             \
+    X(ProgramEmit, AReLinkReIssuesOnTheSameHandle)                                                  \
+    X(ProgramEmit, TheDrawAndDispatchProgramsAreTwoIndependentSlots)                                \
+    X(ProgramEmit, AnUnchangedProgramEmitsNothingAtAll)                                             \
+    X(ProgramEmit, AReIssuedCreateReSendsTheDefaultUniformBlock)                                    \
+    X(ProgramEmit, ADeadProgramsRecordLatchIsRetiredAtItsDeath)
+
+#define MGL_DECLARE_PULL_SKIP(Suite, Name)                                                         \
+    TEST(Suite, Name) { GTEST_SKIP() << "compiled only under MOBILEGL_PIPE_PUSH"; }
+MGL_PROGRAM_EMIT_TEST_LIST(MGL_DECLARE_PULL_SKIP)
+#undef MGL_DECLARE_PULL_SKIP
+#else
+
+namespace {
+    namespace GL = MobileGL::MG_Impl::GLImpl;
+    using GLContext = MG_State::GLState::GLContext;
+    using MG_State::GLState::ProgramObject;
+
+    struct EmitterScope {
+        EmitterScope() { Clear(); }
+        ~EmitterScope() {
+            GL::UseProgram(0);
+            Clear();
+        }
+        EmitterScope(const EmitterScope&) = delete;
+        EmitterScope& operator=(const EmitterScope&) = delete;
+
+        static void Clear() {
+            MGPipeProgramEmitterInstance().Reset();
+            MGPipeProgramEmitterInstance().ResetCounters();
+        }
+    };
+
+    GLContext& Ctx() { return *MG_State::pGLContext; }
+    MGPipeProgramEmitter& Emitter() { return MGPipeProgramEmitterInstance(); }
+
+    const char* kVs = R"(#version 430 core
+uniform vec4 u_value;
+void main() { gl_Position = u_value; }
+)";
+    const char* kFs = R"(#version 430 core
+out vec4 o_color;
+void main() { o_color = vec4(1.0); }
+)";
+    const char* kGs = R"(#version 430 core
+layout(points) in;
+layout(points, max_vertices = 1) out;
+void main() { gl_Position = vec4(0.0); EmitVertex(); }
+)";
+
+    GLuint MakeShader(GLenum stage, const char* source) {
+        const GLuint shader = GL::CreateShader(stage);
+        GL::ShaderSource(shader, 1, &source, nullptr);
+        GL::CompileShader(shader);
+        return shader;
+    }
+
+    GLuint MakeVsFsProgram() {
+        const GLuint program = GL::CreateProgram();
+        GL::AttachShader(program, MakeShader(GL_VERTEX_SHADER, kVs));
+        GL::AttachShader(program, MakeShader(GL_FRAGMENT_SHADER, kFs));
+        GL::LinkProgram(program);
+        GLint linked = GL_FALSE;
+        GL::GetProgramiv(program, GL_LINK_STATUS, &linked);
+        EXPECT_EQ(linked, GL_TRUE) << "the vertex/fragment program did not link";
+        return program;
+    }
+
+    constexpr Uint32 StageBit(ShaderStage stage) { return Uint32{1} << static_cast<Uint32>(stage); }
+
+    // ProgramObject.h says it in as many words and this is the case that holds it: a stage mask
+    // built from the ATTACH list would describe a program that does not exist yet, because
+    // glAttachShader takes effect only at the next link and does not move the link version.
+    // The SPIR-V array beside the mask is indexed by the same snapshot, so the two halves of
+    // the descriptor agree by construction rather than by care.
+    TEST(ProgramEmit, TheStageMaskComesFromTheLinkedSnapshotAndNotTheAttachList) {
+        EmitterScope scope;
+        const GLuint name = MakeVsFsProgram();
+        const SharedPtr<ProgramObject>& program = Ctx().GetProgramObject(name);
+        ASSERT_TRUE(program);
+        const Uint32 linkedMask = MGPipeStageMaskOf(*program);
+        EXPECT_EQ(linkedMask, StageBit(ShaderStage::Vertex) | StageBit(ShaderStage::Fragment));
+
+        // A third stage is attached and NOT linked. The live attach list now has three
+        // shaders; the mask must not move.
+        GL::AttachShader(name, MakeShader(GL_GEOMETRY_SHADER, kGs));
+        EXPECT_EQ(program->GetAttachedShaders().size(), 3u) << "the attach really has to land";
+        EXPECT_EQ(MGPipeStageMaskOf(*program), linkedMask)
+            << "glAttachShader takes effect at the NEXT link and moves no link version";
+
+        GL::LinkProgram(name);
+        GLint linked = GL_FALSE;
+        GL::GetProgramiv(name, GL_LINK_STATUS, &linked);
+        if (linked == GL_TRUE) {
+            EXPECT_EQ(MGPipeStageMaskOf(*program), linkedMask | StageBit(ShaderStage::Geometry))
+                << "and after the relink the snapshot really does carry it";
+        }
+    }
+
+    // D-H6. ~0u is the backends' "never uploaded" sentinel and the frontend's own wrap skips
+    // it; the client must never put it on the wire either, or a server would read its own
+    // record as "nothing has ever been uploaded here" and re-upload for ever.
+    //
+    // PINNED AS A PREDICATE rather than by driving the counter to ~0u, and the reason is
+    // written down instead of hidden: reaching that value takes four billion
+    // MarkUBOContentDirty calls, which is not a test. The predicate is the thing
+    // EmitGlobalConstants consults, so pinning it pins the behaviour, and a deletion of the
+    // guard is a compile error here.
+    TEST(ProgramEmit, TheNeverUploadedSentinelIsNeverEmitted) {
+        EmitterScope scope;
+        EXPECT_EQ(kMGPipeGlobalConstantsNeverUploaded, ~Uint32{0});
+        EXPECT_FALSE(MGPipeGlobalConstantsVersionIsEmittable(kMGPipeGlobalConstantsNeverUploaded));
+        EXPECT_TRUE(MGPipeGlobalConstantsVersionIsEmittable(0u));
+        EXPECT_TRUE(MGPipeGlobalConstantsVersionIsEmittable(1u));
+        EXPECT_TRUE(MGPipeGlobalConstantsVersionIsEmittable(~Uint32{0} - 1u));
+
+        // And the live path never produces it either: whatever the frontend's counter is at,
+        // the record the emitter last built carries an emittable version.
+        const GLuint name = MakeVsFsProgram();
+        GL::UseProgram(name);
+        const SharedPtr<ProgramObject>& program = Ctx().GetProgramObject(name);
+        ASSERT_TRUE(program);
+        program->MarkUBOContentDirty();
+        if (Emitter().EmitGlobalConstants(Ctx()) > 0u) {
+            EXPECT_TRUE(MGPipeGlobalConstantsVersionIsEmittable(Emitter().LastGlobalConstants().Version));
+            EXPECT_EQ(Emitter().LastGlobalConstants().Version, program->GetUBOContentVersion());
+            EXPECT_EQ(Emitter().LastGlobalConstants().Blob.Size, 0u)
+                << "the one Blob rule: a monolith emission does not declare its blob";
+        }
+    }
+
+    // D-H4, and it is a statement about the TRACKER as much as about the emitter: Update() may
+    // not move a program's link completeness in either direction, because answering "did the
+    // shader move" from a version counter is what keeps a compile off the dirty walk. The
+    // emitter is where the join belongs, and it is the same GetProgramForDraw() the verb is
+    // about to make anyway.
+    TEST(ProgramEmit, TheEmitterJoinsAndTheTrackerDoesNot) {
+        EmitterScope scope;
+        const GLuint name = MakeVsFsProgram();
+        GL::UseProgram(name);
+        const SharedPtr<ProgramObject>& program = Ctx().GetProgramObject(name);
+        ASSERT_TRUE(program);
+
+        const Bool completeBefore = program->IsLinkComplete();
+        MGPipeTrackerInstance().Update(Ctx(), MGPipeVerbClass::kDraw);
+        EXPECT_EQ(program->IsLinkComplete(), completeBefore)
+            << "the dirty walk must not force a compile, in either direction";
+
+        Emitter().EmitShaderState(Ctx());
+        EXPECT_TRUE(program->IsLinkComplete()) << "the emitter joins, because the verb would";
+        MGPipeTrackerInstance().Reset();
+    }
+
+    TEST(ProgramEmit, AReLinkReIssuesOnTheSameHandle) {
+        EmitterScope scope;
+        const GLuint name = MakeVsFsProgram();
+        GL::UseProgram(name);
+        const SharedPtr<ProgramObject>& program = Ctx().GetProgramObject(name);
+        ASSERT_TRUE(program);
+
+        ASSERT_GT(Emitter().EmitShaderState(Ctx()), 0u);
+        ASSERT_EQ(Emitter().CreateCount(), 1u);
+        const MGPipeHandle cso = Emitter().LastProgramDesc().Cso;
+        EXPECT_FALSE(MGPipeHandleIsNull(cso));
+        EXPECT_EQ(Emitter().DrawCso(), cso);
+
+        // Nothing moved: no second record, no second bind.
+        Emitter().EmitShaderState(Ctx());
+        EXPECT_EQ(Emitter().CreateCount(), 1u);
+        EXPECT_EQ(Emitter().BindCount(), 1u);
+
+        const Uint32 linkVersionBefore = program->GetLinkVersion();
+        GL::LinkProgram(name);
+        ASSERT_NE(program->GetLinkVersion(), linkVersionBefore) << "the relink really has to move it";
+
+        Emitter().EmitShaderState(Ctx());
+        EXPECT_EQ(Emitter().CreateCount(), 2u);
+        // THE SAME HANDLE. Gen increments only on slot reuse and never on a respecify, so a
+        // relinked program is the same GL object and the server's twin table must not be asked
+        // to mint a second identity for it.
+        EXPECT_EQ(Emitter().LastProgramDesc().Cso, cso);
+        EXPECT_EQ(Emitter().BindCount(), 1u) << "and a re-issue on the bound handle is not a rebind";
+    }
+
+    // Two calls because the frontend has two joins and two PipeInputs slots. With a plain
+    // glUseProgram they name one object, and the record has to say so rather than leaving the
+    // server to guess which of the two a verb meant.
+    TEST(ProgramEmit, TheDrawAndDispatchProgramsAreTwoIndependentSlots) {
+        EmitterScope scope;
+        const GLuint name = MakeVsFsProgram();
+        GL::UseProgram(name);
+        ASSERT_GT(Emitter().EmitShaderState(Ctx()), 0u);
+        EXPECT_EQ(Emitter().DrawCso(), Emitter().DispatchCso());
+        EXPECT_EQ(Emitter().BoundCso(), Emitter().DrawCso());
+        EXPECT_EQ(Emitter().DrawProgramSetCount(), 1u);
+        EXPECT_EQ(Emitter().DispatchProgramSetCount(), 1u);
+
+        // A null handle is legal and means exactly "nothing bound".
+        GL::UseProgram(0);
+        Emitter().EmitShaderState(Ctx());
+        EXPECT_TRUE(MGPipeHandleIsNull(Emitter().DrawCso()));
+        EXPECT_TRUE(MGPipeHandleIsNull(Emitter().DispatchCso()));
+        EXPECT_TRUE(MGPipeHandleIsNull(Emitter().BoundCso()));
+        EXPECT_EQ(Emitter().DrawProgramSetCount(), 2u);
+    }
+
+    TEST(ProgramEmit, AnUnchangedProgramEmitsNothingAtAll) {
+        EmitterScope scope;
+        const GLuint name = MakeVsFsProgram();
+        GL::UseProgram(name);
+        ASSERT_GT(Emitter().EmitShaderState(Ctx()), 0u);
+        // The version-first skip: nothing hashed, nothing copied, nothing emitted, and the
+        // return value is the bytes that went on the wire - zero.
+        EXPECT_EQ(Emitter().EmitShaderState(Ctx()), 0u);
+        EXPECT_EQ(Emitter().CreateCount(), 1u);
+        EXPECT_EQ(Emitter().BindCount(), 1u);
+        EXPECT_EQ(Emitter().DrawProgramSetCount(), 1u);
+    }
+
+    // set_global_constants is suppressed against a (ShaderCso, Version) key, and A RE-ISSUED
+    // create_shader_state CLEARS THE APPLIER's DEFAULT UNIFORM BLOCK (wire's W6). So the key
+    // has to die with the re-issue, or the block is never re-sent and the server draws the
+    // program with a zeroed one while the client's scratch still holds the live values.
+    //
+    // WHICH HALF OF THIS CASE IS THE DISCRIMINATOR, said plainly. The second half - "the block
+    // goes out again after a relink" - is also true without the fix, because
+    // BumpLinkObservableVersions bumps the UBO content version alongside the link version, so
+    // the Version half of the key moves on its own for the one re-issue trigger that exists
+    // today. The FIRST half is the one that goes red when the invalidation is deleted, and it
+    // is the property the contract actually needs: after a re-issue the emitter must hold NO
+    // key at all, so no future re-issue trigger - a recycled slot, a re-issue driven by
+    // anything that does not happen to move the content version - can leave the applier's
+    // cleared block latched as "already sent".
+    TEST(ProgramEmit, AReIssuedCreateReSendsTheDefaultUniformBlock) {
+        EmitterScope scope;
+        const GLuint name = MakeVsFsProgram();
+        GL::UseProgram(name);
+        const SharedPtr<ProgramObject>& program = Ctx().GetProgramObject(name);
+        ASSERT_TRUE(program);
+
+        ASSERT_GT(Emitter().EmitShaderState(Ctx()), 0u);
+        ASSERT_EQ(Emitter().CreateCount(), 1u);
+        // Driven to the fixed point rather than assumed to settle in one call: the first
+        // EmitGlobalConstants reads GetUBOContentVersion() BEFORE GetUBOSize() joins phase B,
+        // and that join bumps the counter, so the first key is one behind by construction.
+        for (int i = 0; i < 8 && Emitter().EmitGlobalConstants(Ctx()) > 0u; ++i) {
+        }
+        const Uint64 setsBefore = Emitter().GlobalConstantsSetCount();
+        ASSERT_GT(setsBefore, 0u) << "this program declares a uniform, so a block must have gone out";
+        const MGPipeHandle cso = Emitter().GlobalConstantsCso();
+        ASSERT_FALSE(MGPipeHandleIsNull(cso));
+        EXPECT_EQ(cso, Emitter().DrawCso());
+        // The latch really is latched.
+        EXPECT_EQ(Emitter().EmitGlobalConstants(Ctx()), 0u);
+        EXPECT_EQ(Emitter().GlobalConstantsSetCount(), setsBefore);
+
+        // A RELINK, which is the one thing that makes AcquireShaderCso re-issue on the same
+        // handle. A failed relink is the case the design worries about - GL keeps a program
+        // that is active for a stage running on its previous executable - and this frontend
+        // additionally clears the phase-B scratch in Link()'s prologue, so the populated-block
+        // half of that scenario is not reachable here; the re-issue is, and it is what the
+        // applier reacts to.
+        const Uint32 linkVersionBefore = program->GetLinkVersion();
+        GL::LinkProgram(name);
+        ASSERT_NE(program->GetLinkVersion(), linkVersionBefore) << "the relink really has to move it";
+
+        Emitter().EmitShaderState(Ctx());
+        ASSERT_EQ(Emitter().CreateCount(), 2u) << "the create really has to be re-issued";
+        EXPECT_TRUE(MGPipeHandleIsNull(Emitter().GlobalConstantsCso()))
+            << "the applier cleared the record's default uniform block on the re-issue, so the "
+               "key that suppresses set_global_constants must not survive it";
+        EXPECT_EQ(Emitter().GlobalConstantsVersion(), kMGPipeGlobalConstantsNeverUploaded);
+
+        // And the block really is sent again.
+        for (int i = 0; i < 8 && Emitter().EmitGlobalConstants(Ctx()) > 0u; ++i) {
+        }
+        EXPECT_GT(Emitter().GlobalConstantsSetCount(), setsBefore);
+    }
+    // FINAL REVIEW C-2: the death helper forwards to this emitter before the slot is freed, so
+    // a dead program's handle no longer reads as published in the record memo between the death
+    // and the recycle (the memo's own Gen test covers only the recycle).
+    TEST(ProgramEmit, ADeadProgramsRecordLatchIsRetiredAtItsDeath) {
+        EmitterScope scope;
+        const GLuint name = MakeVsFsProgram();
+        MGPipeHandle handle{};
+        {
+            const SharedPtr<ProgramObject>& program = Ctx().GetProgramObject(name);
+            ASSERT_TRUE(program);
+            Uint64 bytes = 0;
+            handle = Emitter().AcquireShaderCso(*program, bytes);
+            ASSERT_FALSE(MGPipeHandleIsNull(handle));
+            ASSERT_TRUE(Emitter().RecordIsPublished(handle));
+        }
+        GL::DeleteProgram(name); // not in use: the frontend object dies here
+        EXPECT_FALSE(MGPipeSlots().IsLive(MGPipeKind::ShaderCso, handle));
+        EXPECT_FALSE(Emitter().RecordIsPublished(handle))
+            << "a dead program still reads as published in the program emitter's memo";
+    }
+} // namespace
+#endif // MOBILEGL_PIPE_PUSH
+
+int main(int argc, char** argv) {
+    namespace fs = std::filesystem;
+    const fs::path path =
+        fs::temp_directory_path() / ("mobilegl-programemit-test-" + std::to_string(ProcessId()) + ".log");
+    std::error_code ec;
+    fs::remove(path, ec);
+    g_logPath = path.string();
+#if defined(_WIN32)
+    _putenv_s("MOBILEGL_LOG_FILE_PATH", g_logPath.c_str());
+#else
+    setenv("MOBILEGL_LOG_FILE_PATH", g_logPath.c_str(), 1);
+#endif
+#if MOBILEGL_PIPE_PUSH
+    MobileGL::Initialize();
+#endif
+    ::testing::InitGoogleTest(&argc, argv);
+    const int rc = RUN_ALL_TESTS();
+    fs::remove(path, ec);
+    return rc;
+}

MobileGL/MG_Test/Pipe/ResourceEmitTest.cpp

@@ -56,6 +56,13 @@
 #include <MG_Pipe/MGPipe.h>
 #if MOBILEGL_PIPE_PUSH
 #include <Config.h>
+// MOBILEGL_PIPE_POISON is DERIVED in the header below (PipeInputs.h:20-26) and nowhere
+// else, so a TU that tests it without this include silently reads it as 0. That is
+// invisible in a push build (where it really is 0) and in a verify build (where
+// -DMOBILEGL_PIPE_VERIFY=1 is on the command line); MOBILEGL_BUILD_DISAGGREGATED is the
+// one arming condition that lives behind the header, so a split build is the first place
+// the refusals below stop being fatal while the expectations still say they are.
+#include <MG_Backend/MGPipe/PipeInputs.h>
 #include <MG_Impl/Pipe/ResourceTracker.h>
 #include <MG_Impl/Pipe/SlotAllocator.h>
 #include <MG_Impl/Pipe/VertexInputEmit.h>
@@ -156,6 +163,27 @@ namespace {
         }
     };
 
+    // "A BACKEND IS PRESENT", which since ID-39 is a thing the applier ASKS: every P4a-family
+    // entry point declines a record - and counts RefusedNoConsumer - when no backend has
+    // registered MGPipeResourceOps, because acceptance is a contract with the emitter and an
+    // accepted record nothing will read makes the client clear a dirty flag the legacy pull
+    // path still owed. A case that wants the P4a half of this applier to behave as it does
+    // under DirectGLES scopes this on; the case that wants the OTHER arm simply does not.
+    //
+    // THE TABLE IS EMPTY AND THAT IS DELIBERATE. Its hooks are the BUFFER family's, and every
+    // non-buffer resource row is stored and returned rather than dispatched (see
+    // MGPipeApplyResourceCreate) - so what registering it changes here is the consumer question
+    // and nothing else. It nests: the previous table is restored, not nulled.
+    struct ScopedResourceOps {
+        ScopedResourceOps() : m_saved(MGPipeGetResourceOps()) {
+            static const MGPipeResourceOps kEmpty{};
+            MGPipeSetResourceOps(&kEmpty);
+        }
+        ~ScopedResourceOps() { MGPipeSetResourceOps(m_saved); }
+
+        const MGPipeResourceOps* m_saved;
+    };
+
     MGPResourceDesc BufferDesc(MGPipeHandle res, Uint32 width, Uint32 glName) {
         MGPResourceDesc desc{};
         desc.Resource = res;
@@ -1225,7 +1253,12 @@ namespace {
     TEST(ResourceEmit, TheLiveHostWritesWireFiresOnTheCallAPersistentMapProducerWouldSetItOn) {
 #if !MOBILEGL_PIPE_PUSH
         GTEST_SKIP() << "MOBILEGL_PIPE_PUSH is off: there is no applier in this build";
-#elif !(MOBILEGL_PIPE_POISON || MOBILEGL_PIPE_VERIFY)
+        // MOBILEGL_PIPE_VERIFY alone, NOT `POISON || VERIFY`. PinNoLiveHostWrites is compiled
+        // under `#if MOBILEGL_PIPE_VERIFY` only (PipeApply.cpp:838-853), so in a split build -
+        // where POISON is armed by MOBILEGL_BUILD_DISAGGREGATED but VERIFY is off - the wire
+        // genuinely is compiled out and this case must skip. The wrong disjunction was masked
+        // until now by POISON being invisible in this TU at all (see the include at the top).
+#elif !MOBILEGL_PIPE_VERIFY
         GTEST_SKIP() << "Fatal{PipeLiveHostWrites} is a MOBILEGL_PIPE_VERIFY wire and is compiled out here";
 #elif !MGTEST_HAVE_FORK
         GTEST_SKIP() << "no fork on this platform; the wire's verdict is std::abort()";
@@ -1323,6 +1356,361 @@ namespace {
 #endif
     }
 
+    // =====================================================================================
+    // P4a: the four resource entry points now BRANCH ON THE DESCRIPTOR'S TARGET.
+    //
+    // The slot spaces of kinds Buffer, Texture and Renderbuffer are independent - the client
+    // allocator is per kind - so one slot-indexed table would alias three live objects onto one
+    // record. These cases are about the branch and nothing else: which table a call lands in,
+    // that the three do not see each other, and that a target or a kind the catalogue does not
+    // name is refused rather than routed to whichever table came first. The texture family's
+    // own behaviour (parameters, the sub-data validator, the pending-upload set) is in
+    // TextureEmitTest beside the emitter cases it belongs with.
+    // =====================================================================================
+
+#if MOBILEGL_PIPE_PUSH
+    MGPResourceDesc TargetedDesc(MGPipeHandle res, MGPipeResourceTarget target, Uint32 width, Uint32 glName) {
+        MGPResourceDesc desc = BufferDesc(res, width, glName);
+        desc.Target = static_cast<Uint8>(target);
+        return desc;
+    }
+
+    MGPHandleOnly KindHandle(MGPipeHandle res, MGPipeKind kind) {
+        return MGPHandleOnly{res, static_cast<Uint32>(kind), 0};
+    }
+#endif
+
+    // ONE SLOT NUMBER, THREE LIVE OBJECTS, THREE RECORDS. This is the case that fails the
+    // instant the applier goes back to one table: every assertion below is about slot 7 being
+    // three different things at once, which is exactly what the client allocator hands out.
+    TEST(ResourceEmit, TheThreeResourceKindsKeepTheirOwnSlotSpaceAndDoNotSeeEachOther) {
+#if !MOBILEGL_PIPE_PUSH
+        GTEST_SKIP() << "MOBILEGL_PIPE_PUSH is off: there is no applier in this build";
+#else
+        ApplierGuard guard;
+        // The texture and renderbuffer rows below are P4a's, and P4a's belt declines those on a
+        // backend that consumes none of them (ID-39) - so this case says which arm it is about.
+        ScopedResourceOps consumer;
+        const MGPipeHandle shared{7, 3};
+
+        MGPipeApplyResourceCreate(TargetedDesc(shared, MGPipeResourceTarget::Buffer, 0, 11));
+        MGPipeApplyResourceCreate(TargetedDesc(shared, MGPipeResourceTarget::Tex2D, 0, 22));
+        MGPipeApplyResourceCreate(TargetedDesc(shared, MGPipeResourceTarget::Renderbuffer, 0, 33));
+
+        ASSERT_GT(MGPipeApplier().Resources.size(), 7u);
+        ASSERT_GT(MGPipeApplier().TextureResources.size(), 7u);
+        ASSERT_GT(MGPipeApplier().RenderbufferResources.size(), 7u);
+        EXPECT_EQ(MGPipeApplier().Resources[7].Desc.GlNameForDiag, 11u);
+        EXPECT_EQ(MGPipeApplier().TextureResources[7].Desc.GlNameForDiag, 22u);
+        EXPECT_EQ(MGPipeApplier().RenderbufferResources[7].Desc.GlNameForDiag, 33u);
+
+        // A respecify of one of them moves ONE record's serial and one record's extent.
+        MGPipeApplyResourceRespecify(TargetedDesc(shared, MGPipeResourceTarget::Tex2D, 256, 22), nullptr);
+        EXPECT_EQ(MGPipeApplier().TextureResources[7].Desc.Width, 256u);
+        EXPECT_EQ(MGPipeApplier().TextureResources[7].Serial, 1u);
+        EXPECT_EQ(MGPipeApplier().Resources[7].Desc.Width, 0u) << "a texture respecify moved the buffer";
+        EXPECT_EQ(MGPipeApplier().Resources[7].Serial, 0u);
+        EXPECT_EQ(MGPipeApplier().RenderbufferResources[7].Serial, 0u);
+
+        // A renderbuffer restorage is the publication D-D2 asks for: the frontend raises no
+        // version for it, so the emission IS the notice, and the applier holds the new extent.
+        MGPipeApplyResourceRespecify(TargetedDesc(shared, MGPipeResourceTarget::Renderbuffer, 1024, 33),
+                                     nullptr);
+        EXPECT_EQ(MGPipeApplier().RenderbufferResources[7].Desc.Width, 1024u);
+        EXPECT_EQ(MGPipeApplier().RenderbufferResources[7].Serial, 1u);
+
+        // And a destroy takes the record its KIND names, and only that one.
+        MGPipeApplyResourceDestroy(KindHandle(shared, MGPipeKind::Texture));
+        EXPECT_FALSE(MGPipeApplier().TextureResources[7].Live);
+        EXPECT_EQ(MGPipeApplier().TextureResources[7].Gen, 3u) << "a destroy keeps the generation";
+        EXPECT_TRUE(MGPipeApplier().Resources[7].Live) << "a texture destroy dropped the buffer's record";
+        EXPECT_TRUE(MGPipeApplier().RenderbufferResources[7].Live);
+        EXPECT_EQ(MGPipeApplier().RefusedResourceCalls, 0u);
+#endif
+    }
+
+    // ID-39: THE APPLIER'S HALF OF THE "NO CONSUMER" RULE, over every P4a-family entry point.
+    //
+    // WHY AN APPLIER ASKS A QUESTION ABOUT THE BACKEND AT ALL is written beside
+    // MGPipeApplierState::RefusedNoConsumer: acceptance became a CONTRACT WITH THE CLIENT at
+    // ID-18 M3 - the emitters clear a texture level's dirty flags, advance their descriptor
+    // mirrors and latch their suppressors on the answer these calls return - so an applier that
+    // accepts a record nothing in the process will ever read makes the client forget work the
+    // legacy pull path still owed. On DirectVulkan, which registers no MGPipeResourceOps and
+    // has none of P4a's twins, that put 66 texture-upload-shaped integration-gpu cases red on
+    // the push build while the pull build stayed 966/966 green.
+    //
+    // IT IS A BELT AND NOT THE GATE. The client's gate is FamilyIsLive in
+    // MG_Impl/Pipe/PipeFill.cpp (pinned by TextureEmit.WithNoBackendConsumerTheFamilyGateIsFalse
+    // AndNothingReachesTheApplier) and it stops the emission upstream. This is under it, and it
+    // is not redundant: GL_Framebuffer.cpp's PipePublishFramebufferByName reaches the
+    // framebuffer emitter DIRECTLY at the fifteen DSA sites, without passing through PipeFill,
+    // so set_framebuffer_state is a record that can arrive here on a backend with no consumer.
+    //
+    // THE DEATH PATHS ARE DELIBERATELY NOT IN THE LIST and the second half of the case says so:
+    // a destroy is idempotent cleanup that must keep working whatever the registration did.
+    TEST(ResourceEmit, EveryP4aFamilyEntryPointDeclinesWhenNoBackendRegisteredTheConsumer) {
+#if !MOBILEGL_PIPE_PUSH
+        GTEST_SKIP() << "MOBILEGL_PIPE_PUSH is off: there is no applier in this build";
+#else
+        ApplierGuard guard; // leaves the table UNREGISTERED, which is this half's whole point
+        ASSERT_EQ(MGPipeGetResourceOps(), nullptr);
+
+        const MGPipeHandle texture{7, 3};
+        const MGPipeHandle cso{9, 1};
+        const MGPipeHandle fbo{4, 2};
+
+        MGPTextureParams params{};
+        params.Res = texture;
+        params.BuiltinSampler = cso;
+
+        MGPSubData upload{};
+        upload.Res = texture;
+        upload.Target = MGPipePackSubDataTarget(static_cast<Uint32>(MGPipeResourceTarget::Tex2D), 0u);
+
+        MGPFramebufferState fboState{};
+        fboState.Fbo = fbo;
+        fboState.Target = static_cast<Uint8>(MGPipeFramebufferTarget::Draw);
+
+        MGPSamplerDesc samplerDesc{};
+        samplerDesc.Cso = cso;
+        const SamplerParameters samplerParams{};
+
+        MGPSamplerView view{};
+        view.Cso = cso;
+        view.Texture = texture;
+
+        const MGPSamplerViews viewSet{0, 1, 0};
+        const MGPBoundView viewTail[1]{};
+        const MGPSamplerStates stateSet{0, 1, 0};
+        const MGPipeHandle stateTail[1]{kMGPipeNullHandle};
+        const MGPShaderImages imageSet{0, 1, 0};
+        const MGPImageView imageTail[1]{};
+
+        MGPProgramDesc program{};
+        program.Cso = cso;
+        program.StageMask = 0x3u;
+        const MG_State::GLState::LinkArtifacts link;
+        const MG_State::GLState::SpirvArtifacts spirv;
+
+        MGPGlobalConstants constants{};
+        constants.ShaderCso = cso;
+
+        const MGPHandleOnly csoHandle{cso, static_cast<Uint32>(MGPipeKind::ShaderCso), 0};
+
+        // ---- with no consumer: every one of them declines, and NOTHING is stored ----
+        EXPECT_FALSE(MGPipeApplyResourceCreate(TargetedDesc(texture, MGPipeResourceTarget::Tex2D, 0, 22)));
+        EXPECT_FALSE(
+            MGPipeApplyResourceRespecify(TargetedDesc(texture, MGPipeResourceTarget::Tex2D, 64, 22), nullptr));
+        EXPECT_FALSE(MGPipeApplyResourceSubData(upload, nullptr));
+        MGPipeApplySetTextureParams(params);
+        MGPipeApplySetFramebufferState(fboState);
+        MGPipeApplyCreateSamplerState(samplerDesc, &samplerParams);
+        MGPipeApplyCreateSamplerView(view);
+        MGPipeApplySetSamplerViews(viewSet, viewTail);
+        MGPipeApplyBindSamplerStates(stateSet, stateTail);
+        MGPipeApplySetShaderImages(imageSet, imageTail);
+        MGPipeApplyCreateShaderState(program, &link, &spirv);
+        MGPipeApplyBindShaderState(csoHandle);
+        MGPipeApplySetDrawProgram(csoHandle);
+        MGPipeApplySetDispatchProgram(csoHandle);
+        MGPipeApplySetGlobalConstants(constants, nullptr);
+
+        // FIFTEEN CALLS, FIFTEEN REFUSALS, AND THE NUMBER IS THE ASSERTION: an entry point that
+        // is added to a P4a family later and forgets the belt makes this line fail rather than
+        // silently accepting a record on a backend that reads none.
+        EXPECT_EQ(MGPipeApplier().RefusedNoConsumer, 15u);
+        // AND NOT ONE OF THE OTHER THREE MOVED. The refusal is a configuration fact, not a seam
+        // defect, so it must not read as one to an operator grepping the counters.
+        EXPECT_EQ(MGPipeApplier().RefusedResourceCalls, 0u);
+        EXPECT_EQ(MGPipeApplier().RefusedObjectCalls, 0u);
+        EXPECT_EQ(MGPipeApplier().StaleFramebufferRecordLookups, 0u);
+
+        // NOTHING IS LIVE, which is the property, rather than "no table exists". The belt stands
+        // AFTER each entry point's own record-shape checks so that a malformed record is
+        // Fatal{ProtocolCorruption} on every backend and not only on the ones that consume - and
+        // the bound check for the four create-shaped calls IS RecordAt, which grows the table to
+        // the slot on its way to answering. So a refused create may leave a zeroed row behind
+        // and stores nothing in it. It costs nothing where it matters: on a backend with no
+        // consumer the client's gate emits none of these at all, and the one record that reaches
+        // this applier without passing that gate - set_framebuffer_state, published by name from
+        // GL_Framebuffer.cpp - is declined in front of its RecordAt.
+        const auto nothingLiveAt = [](const auto& table, SizeT slot) {
+            return table.size() <= slot || !table[slot].Live;
+        };
+        EXPECT_TRUE(nothingLiveAt(MGPipeApplier().TextureResources, 7));
+        EXPECT_TRUE(nothingLiveAt(MGPipeApplier().SamplerCsos, 9));
+        EXPECT_TRUE(nothingLiveAt(MGPipeApplier().SamplerViewCsos, 9));
+        EXPECT_TRUE(nothingLiveAt(MGPipeApplier().ShaderCsos, 9));
+        // set_framebuffer_state's table is the one that must not even be grown: it is declined
+        // in front of its RecordAt, because it is the one call a backend with no consumer can
+        // actually receive.
+        EXPECT_TRUE(MGPipeApplier().FramebufferRecords.empty());
+        EXPECT_EQ(MGPipeApplier().SamplerViewCount, 0u);
+        EXPECT_EQ(MGPipeApplier().SamplerStateCount, 0u);
+        EXPECT_EQ(MGPipeApplier().ShaderImageCount, 0u);
+        EXPECT_TRUE(MGPipeHandleIsNull(MGPipeApplier().BoundShaderCso));
+        EXPECT_TRUE(MGPipeHandleIsNull(MGPipeApplier().DrawProgram));
+        EXPECT_TRUE(MGPipeHandleIsNull(MGPipeApplier().DispatchProgram));
+        EXPECT_TRUE(MGPipeHandleIsNull(
+            MGPipeApplier().BoundFramebuffer[static_cast<SizeT>(MGPipeFramebufferTarget::Draw)]));
+
+        // ---- and with one, every one of them lands. Same records, same order ----
+        {
+            ScopedResourceOps consumer;
+            const Uint64 refusalsBefore = MGPipeApplier().RefusedNoConsumer;
+
+            EXPECT_TRUE(
+                MGPipeApplyResourceCreate(TargetedDesc(texture, MGPipeResourceTarget::Tex2D, 0, 22)));
+            EXPECT_TRUE(MGPipeApplyResourceRespecify(
+                TargetedDesc(texture, MGPipeResourceTarget::Tex2D, 64, 22), nullptr));
+            MGPipeApplySetTextureParams(params);
+            MGPipeApplySetFramebufferState(fboState);
+            MGPipeApplyCreateSamplerState(samplerDesc, &samplerParams);
+            MGPipeApplyCreateSamplerView(view);
+            MGPipeApplySetSamplerViews(viewSet, viewTail);
+            MGPipeApplyBindSamplerStates(stateSet, stateTail);
+            MGPipeApplySetShaderImages(imageSet, imageTail);
+            MGPipeApplyCreateShaderState(program, &link, &spirv);
+            MGPipeApplyBindShaderState(csoHandle);
+            MGPipeApplySetDrawProgram(csoHandle);
+            MGPipeApplySetDispatchProgram(csoHandle);
+            MGPipeApplySetGlobalConstants(constants, nullptr);
+
+            EXPECT_EQ(MGPipeApplier().RefusedNoConsumer, refusalsBefore);
+            ASSERT_GT(MGPipeApplier().TextureResources.size(), 7u);
+            EXPECT_TRUE(MGPipeApplier().TextureResources[7].Live);
+            EXPECT_EQ(MGPipeApplier().TextureResources[7].Desc.Width, 64u);
+            EXPECT_EQ(MGPipeApplier().TextureResources[7].Params.BuiltinSampler, cso);
+            ASSERT_GT(MGPipeApplier().FramebufferRecords.size(), 4u);
+            EXPECT_TRUE(MGPipeApplier().FramebufferRecords[4].Live);
+            EXPECT_EQ(MGPipeApplier().BoundFramebuffer[static_cast<SizeT>(MGPipeFramebufferTarget::Draw)],
+                      fbo);
+            ASSERT_GT(MGPipeApplier().SamplerCsos.size(), 9u);
+            EXPECT_TRUE(MGPipeApplier().SamplerCsos[9].Live);
+            ASSERT_GT(MGPipeApplier().SamplerViewCsos.size(), 9u);
+            EXPECT_TRUE(MGPipeApplier().SamplerViewCsos[9].Live);
+            ASSERT_GT(MGPipeApplier().ShaderCsos.size(), 9u);
+            EXPECT_TRUE(MGPipeApplier().ShaderCsos[9].Live);
+            EXPECT_EQ(MGPipeApplier().SamplerViewCount, 1u);
+            EXPECT_EQ(MGPipeApplier().SamplerStateCount, 1u);
+            EXPECT_EQ(MGPipeApplier().ShaderImageCount, 1u);
+            EXPECT_EQ(MGPipeApplier().BoundShaderCso, cso);
+            EXPECT_EQ(MGPipeApplier().DrawProgram, cso);
+            EXPECT_EQ(MGPipeApplier().DispatchProgram, cso);
+            // resource_subdata's ACCEPTED path wants a real destination box against real
+            // storage, which is a texture-emitter fixture and not this file's; it is proved end
+            // to end by TextureEmit.WithNoBackendConsumerTheFamilyGateIsFalseAndNothingReaches
+            // TheApplier's second half (SubDataCount 1, RefusedSubDataCount 0). Driving a
+            // half-built record through it here would trip the upload validator's own wire,
+            // which is a different rule and not this case's.
+
+            // AND THE DEATH PATHS ARE NOT BELTED, which is the other half of the ruling: they
+            // are idempotent cleanup and they run on whatever the registration is. Driven with
+            // the table registered here and asserted UNCOUNTED, so that a later commit which
+            // adds them to the belt has to change this line.
+            MGPipeApplyDeleteShaderState(csoHandle);
+            MGPipeApplyResourceDestroy(KindHandle(texture, MGPipeKind::Texture));
+            EXPECT_EQ(MGPipeApplier().RefusedNoConsumer, refusalsBefore);
+            EXPECT_FALSE(MGPipeApplier().ShaderCsos[9].Live);
+            EXPECT_FALSE(MGPipeApplier().TextureResources[7].Live);
+        }
+#endif
+    }
+
+    // Neither branch may fall through to a table it was not named. A target or a kind outside
+    // the catalogue would otherwise land in whichever table the code happened to reach first,
+    // and destroy a live object of a kind the call was never about.
+    TEST(ResourceEmit, AResourceTargetOrKindTheCatalogueDoesNotNameIsRefusedRatherThanRouted) {
+#if !MOBILEGL_PIPE_PUSH
+        GTEST_SKIP() << "MOBILEGL_PIPE_PUSH is off: there is no applier in this build";
+#else
+        ApplierGuard guard;
+        const MGPipeHandle res{5, 1};
+
+        MGPResourceDesc unnamed = BufferDesc(res, 0, 44);
+        unnamed.Target = static_cast<Uint8>(MGPipeResourceTarget::Count);
+        ExpectRefusedNaming("resource_create {slot=5, gen=1, glName=44}: the descriptor names no resource "
+                            "target",
+                            [&unnamed]() { MGPipeApplyResourceCreate(unnamed); });
+        EXPECT_TRUE(MGPipeApplier().Resources.empty());
+        EXPECT_TRUE(MGPipeApplier().TextureResources.empty());
+        EXPECT_TRUE(MGPipeApplier().RenderbufferResources.empty());
+
+        ExpectRefusedNaming("resource_respecify {slot=5, gen=1, glName=44}: the descriptor names no "
+                            "resource target",
+                            [&unnamed]() { MGPipeApplyResourceRespecify(unnamed, nullptr); });
+
+        const MGPHandleOnly wrongKind = KindHandle(res, MGPipeKind::SamplerCso);
+        ExpectRefusedNaming("resource_destroy {slot=5, gen=1}: the handle names no resource kind",
+                            [&wrongKind]() { MGPipeApplyResourceDestroy(wrongKind); });
+
+        // AND unmap_persistent GIVES THE SAME VERDICT, because it is the only one of the four
+        // buffer-only calls that carries a discriminator at all. An assertion here is not a
+        // check: MOBILEGL_ASSERT compiles out at INFO, which is what all three gate builds and
+        // every shipped build are, so a texture-kinded record used to walk into ResolveResource
+        // and alias whatever BUFFER holds that slot - which is exactly what the destroy's Fatal
+        // above exists to stop. The live buffer at slot 5 is what makes the aliasing reachable.
+        MGPipeApplyResourceCreate(BufferDesc(res, 0, 44));
+        MGPipeApplyResourceRespecify(BufferDesc(res, 256, 44), nullptr);
+        ASSERT_TRUE(MGPipeApplier().Resources[5].Live);
+        const MGPHandleOnly textureKind = KindHandle(res, MGPipeKind::Texture);
+        ExpectRefusedNaming("unmap_persistent {slot=5, gen=1}: the persistent donation is the buffer "
+                            "family's and the handle names another kind",
+                            [&textureKind]() { MGPipeApplyUnmapPersistent(textureKind); });
+
+        EXPECT_EQ(MGPipeApplier().RefusedResourceCalls, 0u)
+            << "a corrupt record is not a dropped call and must not be counted as one";
+#endif
+    }
+
+    // A texture's resource calls reach NO backend function pointer, and that is the structural
+    // decision the phase rests on rather than an omission: nothing in the texture family
+    // dispatches at GL-call time today, so the record IS the publication. A spy table that saw
+    // one of them would mean P4a had grown an op-table path nobody designed.
+    TEST(ResourceEmit, NoTextureOrRenderbufferResourceCallReachesTheBackendOpTable) {
+#if !MOBILEGL_PIPE_PUSH
+        GTEST_SKIP() << "MOBILEGL_PIPE_PUSH is off: there is no applier in this build";
+#else
+        ApplierGuard guard;
+        g_spy = SpyState{};
+        MGPipeSetResourceOps(&kSpyOps);
+        const MGPipeHandle texture{3, 1};
+        const MGPipeHandle renderbuffer{4, 1};
+        const Uint8 texels[64] = {};
+
+        MGPipeApplyResourceCreate(TargetedDesc(texture, MGPipeResourceTarget::Tex2D, 0, 55));
+        MGPipeApplyResourceRespecify(TargetedDesc(texture, MGPipeResourceTarget::Tex2D, 8, 55), nullptr);
+        MGPipeApplyResourceCreate(TargetedDesc(renderbuffer, MGPipeResourceTarget::Renderbuffer, 0, 66));
+        MGPipeApplyResourceRespecify(TargetedDesc(renderbuffer, MGPipeResourceTarget::Renderbuffer, 8, 66),
+                                     nullptr);
+        MGPSubData upload{};
+        upload.Res = texture;
+        upload.Target = static_cast<Uint16>(MGPipeResourceTarget::Tex2D);
+        upload.UnionBox = MGPBox{0, 0, 0, 4, 4, 1};
+        MGPipeApplyResourceSubData(upload, texels);
+        MGPipeApplyResourceDestroy(KindHandle(texture, MGPipeKind::Texture));
+        MGPipeApplyResourceDestroy(KindHandle(renderbuffer, MGPipeKind::Renderbuffer));
+
+        EXPECT_EQ(g_spy.Creates, 0u);
+        EXPECT_EQ(g_spy.Respecifies, 0u);
+        EXPECT_EQ(g_spy.SubDatas, 0u);
+        EXPECT_EQ(g_spy.Destroys, 0u);
+
+        // The same five calls on a BUFFER still dispatch, which is what proves the count above
+        // is the branch working rather than the table being uninstalled.
+        const MGPipeHandle buffer{3, 1};
+        MGPipeApplyResourceCreate(BufferDesc(buffer, 0, 77));
+        MGPipeApplyResourceRespecify(BufferDesc(buffer, 64, 77), nullptr);
+        MGPipeApplyResourceSubData(BufferWrite(buffer, 0, 16), texels);
+        MGPipeApplyResourceDestroy(BufferHandle(buffer));
+        EXPECT_EQ(g_spy.Creates, 1u);
+        EXPECT_EQ(g_spy.Respecifies, 1u);
+        EXPECT_EQ(g_spy.SubDatas, 1u);
+        EXPECT_EQ(g_spy.Destroys, 1u);
+#endif
+    }
+
 #if !MOBILEGL_PIPE_PUSH
     // G2 REQUIRES THE PULL AND PUSH ctest NAME SETS TO BE IDENTICAL, name for name, so a
     // push-only case cannot be ABSENT from a pull build - it has to be there and SKIP. This

MobileGL/MG_Test/Pipe/TrackerTest.cpp

@@ -76,6 +76,15 @@ namespace {
     X(TrackerWalk, TheIndexBufferBitDoesNotFireOnAnUnrelatedBufferWrite) \
     X(TrackerWalk, TheIndexBufferBitFiresWhenTheSlotVersionWrapsOntoADifferentBuffer) \
     X(TrackerWalk, ABaseInstanceSurvivesTheFirstWalkOnAFreshContext) \
+    X(TrackerWalk, ASamplerBindAloneFiresTheSamplerStateBit) \
+    X(TrackerWalk, ARestagedProgramPipelineFiresTheProgramBits) \
+    X(TrackerWalk, ARelinkOfAStageProgramFiresTheProgramBits) \
+    X(TrackerWalk, UseProgramZeroLeavesTheBoundPipelineDrivingTheProgramBits) \
+    X(TrackerAggregates, ATextureStorageDefinitionMovesTheFramebufferAggregateToo) \
+    X(TrackerAggregates, ARenderbufferStorageDefinitionMovesTheFramebufferAggregate) \
+    X(TrackerWalk, AProgramSwitchAloneFiresTheSamplerViewBit) \
+    X(TrackerWalk, ATextureParameterAloneFiresTheSamplerViewBit) \
+    X(TrackerWalk, AProgramSwitchBetweenEqualImageUnitCountersFiresTheShaderImageBit) \
     X(TrackerAttribPayload, AFloatWriteCarriesTheFloatBitsAndNamesItsClass) \
     X(TrackerAttribPayload, AnIntWriteCarriesTheIntWordsAndNamesItsClass) \
     X(TrackerAttribPayload, AUintWriteCarriesTheUintWordsAndNamesItsClass) \
@@ -228,6 +237,39 @@ namespace {
         SUCCEED();
     }
 
+    // P4a FABLE SEAM F-3. set_framebuffer_state INLINES an attachment's format, extent and
+    // samples (D-C1), so the setters that define a texture's storage are setters of a
+    // framebuffer-record field - and the record-field -> setter -> shutter rule (Tracker.h's
+    // table) says they must move the aggregate bit 11 reads. They still move the params
+    // aggregate they always moved; what this case pins is the SECOND bump, which the
+    // "moves only" cases above cannot see and which is the whole of F-3's fix.
+    TEST_F(TrackerAggregates, ATextureStorageDefinitionMovesTheFramebufferAggregateToo) {
+        const auto& tex = Ctx().CreateTextureObject(3, TextureTarget::Texture2D);
+        ASSERT_TRUE(tex != nullptr);
+        const Snapshot before = Snap();
+        tex->SetInternalFormat(MobileGL::TextureInternalFormat::RGBA8);
+        const Snapshot after = Snap();
+        EXPECT_GT(after[MGPipeAggregate::FramebufferAttachment], before[MGPipeAggregate::FramebufferAttachment])
+            << "a texture whose storage is redefined WHILE ATTACHED left set_framebuffer_state "
+               "describing the previous format (F-3)";
+        EXPECT_GT(after[MGPipeAggregate::TextureParams], before[MGPipeAggregate::TextureParams]);
+        EXPECT_EQ(after[MGPipeAggregate::TextureContent], before[MGPipeAggregate::TextureContent]);
+        EXPECT_EQ(after[MGPipeAggregate::VaoAttribute], before[MGPipeAggregate::VaoAttribute]);
+        EXPECT_EQ(after[MGPipeAggregate::BufferChange], before[MGPipeAggregate::BufferChange]);
+        EXPECT_EQ(after[MGPipeAggregate::VertexAttribDefault], before[MGPipeAggregate::VertexAttribDefault]);
+    }
+
+    // The renderbuffer twin, and the one that had NO aggregate at all before: its three storage
+    // setters bumped no version and raised no notice (D-D2 closed the resource record by emitting
+    // from the entry point and left the framebuffer record stale).
+    TEST_F(TrackerAggregates, ARenderbufferStorageDefinitionMovesTheFramebufferAggregate) {
+        const auto& rbo = Ctx().CreateRenderbufferObject(1);
+        ASSERT_TRUE(rbo != nullptr);
+        const Snapshot before = Snap();
+        rbo->AllocateStorage(IntVec2{8, 8});
+        ExpectOnly(MGPipeAggregate::FramebufferAttachment, before, Snap());
+    }
+
     // ===================================================================================
     // The dirty walk itself, and the render-state emission it drives (P2 brief D4, D6, D7)
     // ===================================================================================
@@ -320,15 +362,29 @@ namespace {
     // keeps the name it was born with and follows the phase constant instead of a literal
     // five: what it has always asserted is "a bit names a subsystem if and only if this build
     // emits a call for it", which is the property the emission gate and the residual-fill
-    // skip both rest on. P3a took the vertex-input family over, so the set it compares
-    // against is now kMGPipeDirtyEmittedAtP3a - and a bit that gained an arm without gaining
-    // an emitter, or the reverse, still fails here.
+    // skip both rest on. P3a took the vertex-input family over and P4a takes seven more bits
+    // across four subsystems, so the set it compares against is now kMGPipeDirtyEmittedAtP4a -
+    // and a bit that gained an arm without gaining an emitter, or the reverse, still fails
+    // here.
     TEST_F(TrackerWalk, OnlyTheFiveEmittedBitsNameASubsystem) {
         for (SizeT i = 0; i < kMGPipeDirtyCount; ++i) {
             const auto bit = static_cast<MGPipeDirty>(i);
-            const Bool emitted = (kMGPipeDirtyEmittedAtP3a & MGPipeDirtyBit(bit)) != 0;
+            const Bool emitted = (kMGPipeDirtyEmittedAtP4a & MGPipeDirtyBit(bit)) != 0;
             EXPECT_EQ(MGPipeSubsystemForDirty(bit) != 0, emitted) << kMGPipeDirtyNames[i];
         }
+        // Each phase's constant SURVIVES as the next phase's A/B control, so the three are
+        // pinned as a chain rather than one being edited into the next: 0x1ff is P4a's "T2"
+        // arm and 0x7f is P3a's, and an operator's recorded mask has to keep meaning what it
+        // meant.
+        EXPECT_EQ(kMGPipeDirtyEmittedAtP4a & kMGPipeDirtyEmittedAtP3a, kMGPipeDirtyEmittedAtP3a);
+        EXPECT_EQ(kMGPipeDirtyEmittedAtP3a & kMGPipeDirtyEmittedAtP2, kMGPipeDirtyEmittedAtP2);
+        // The three bits P4a still does not emit for - the const-buffer, shader-buffer and
+        // stream-output sets - name no subsystem, so their fields keep going through the
+        // residual fill. Stated positively as well as through the loop above, because "only
+        // these three are left" is the phase's own scope statement.
+        EXPECT_EQ(MGPipeSubsystemForDirty(MGPipeDirty::NewConstBuffers), 0u);
+        EXPECT_EQ(MGPipeSubsystemForDirty(MGPipeDirty::NewShaderBuffers), 0u);
+        EXPECT_EQ(MGPipeSubsystemForDirty(MGPipeDirty::NewSoTargets), 0u);
         EXPECT_EQ(MGPipeSubsystemForDirty(MGPipeDirty::NewRenderState), kMGPipeSubsystemRenderState);
         EXPECT_EQ(MGPipeSubsystemForDirty(MGPipeDirty::NewPixelPack), kMGPipeSubsystemPixelPack);
         EXPECT_EQ(MGPipeSubsystemForDirty(MGPipeDirty::NewPatchState), kMGPipeSubsystemPatchState);
@@ -339,6 +395,26 @@ namespace {
         EXPECT_EQ(MGPipeSubsystemForDirty(MGPipeDirty::NewVertexElements), kMGPipeSubsystemVertexInput);
         EXPECT_EQ(MGPipeSubsystemForDirty(MGPipeDirty::NewVertexBuffers), kMGPipeSubsystemVertexInput);
         EXPECT_EQ(MGPipeSubsystemForDirty(MGPipeDirty::NewIndexBuffer), kMGPipeSubsystemVertexInput);
+        // P4a's seven, across FOUR subsystems, and the grouping is the whole point: the three
+        // program bits are one family because an operator switching programs off has to get
+        // the whole legacy arm, and so are the three unit-set bits.
+        EXPECT_EQ(MGPipeSubsystemForDirty(MGPipeDirty::NewShader), kMGPipeSubsystemPrograms);
+        EXPECT_EQ(MGPipeSubsystemForDirty(MGPipeDirty::NewShaderBindings), kMGPipeSubsystemPrograms);
+        EXPECT_EQ(MGPipeSubsystemForDirty(MGPipeDirty::NewGlobalConstants), kMGPipeSubsystemPrograms);
+        EXPECT_EQ(MGPipeSubsystemForDirty(MGPipeDirty::NewFramebuffer), kMGPipeSubsystemFramebuffer);
+        EXPECT_EQ(MGPipeSubsystemForDirty(MGPipeDirty::NewSamplerViews), kMGPipeSubsystemSamplers);
+        EXPECT_EQ(MGPipeSubsystemForDirty(MGPipeDirty::NewSamplers), kMGPipeSubsystemSamplers);
+        EXPECT_EQ(MGPipeSubsystemForDirty(MGPipeDirty::NewShaderImages), kMGPipeSubsystemSamplers);
+        // AND NO BIT NAMES THE TEXTURE-RESOURCE SUBSYSTEM. Its calls are dispatched from the
+        // GL entry points that cause them - a constructor, a storage definition, a
+        // glTexParameter - not from a dirty walk, exactly as P3a's buffer family is, so a bit
+        // that started naming it would gate the emission twice and the two gates would
+        // disagree the first time one of them was edited.
+        for (SizeT i = 0; i < kMGPipeDirtyCount; ++i) {
+            EXPECT_NE(MGPipeSubsystemForDirty(static_cast<MGPipeDirty>(i)),
+                      kMGPipeSubsystemTextureResources)
+                << kMGPipeDirtyNames[i];
+        }
     }
 
     TEST_F(TrackerWalk, TheFirstWalkOnAFreshContextPublishesEverything) {
@@ -584,6 +660,197 @@ namespace {
         m_cache.Reset();
     }
 
+    // ===================================================================================
+    // P4a c0d: the two under-fires that only a bit WITH an emitter can be hurt by
+    // ===================================================================================
+
+    // BIT 13 IS WHAT bind_sampler_states IS EMITTED OFF (PipeFill.cpp gates EmitSamplerStates
+    // on NEW_SAMPLERS), and glBindSampler moved neither half of what its shutter used to read:
+    // GL_Sampler.cpp's BindSampler_State calls NoteTextureUnitTouched and then
+    // TextureUnit::SetSamplerObject, and BOTH of those bump the TEXTURE BIND generation, which
+    // is bit 12's. The only writers of the sampling-resolution generation are parameter
+    // changes. This case makes those two calls, in that order, with nothing else moving.
+    TEST_F(TrackerWalk, ASamplerBindAloneFiresTheSamplerStateBit) {
+        ASSERT_TRUE(Ctx().CreateSamplerObject(1) != nullptr);
+        ASSERT_TRUE(Ctx().CreateSamplerObject(2) != nullptr);
+
+        Ctx().NoteTextureUnitTouched(3);
+        Ctx().GetTextureUnitObject(3).SetSamplerObject(Ctx().GetSamplerObject(1));
+        Walk();
+        ASSERT_EQ(Walk(), 0u) << "the fixture did not reach a steady state";
+
+        // The one and only change: unit 3 now carries a DIFFERENT sampler object, whose
+        // parameters happen to differ from the first one's. No glSamplerParameter*, no
+        // glTexParameter*, so the sampling-resolution generation cannot have moved.
+        Ctx().NoteTextureUnitTouched(3);
+        Ctx().GetTextureUnitObject(3).SetSamplerObject(Ctx().GetSamplerObject(2));
+        const Uint32 dirty = Walk();
+        EXPECT_NE(dirty & MGPipeDirtyBit(MGPipeDirty::NewSamplers), 0u)
+            << "bind_sampler_states is emitted off NEW_SAMPLERS and never saw the sampler bind";
+        EXPECT_NE(dirty & MGPipeDirtyBit(MGPipeDirty::NewSamplerViews), 0u)
+            << "the view set is re-resolved on a sampler bind too - completeness depends on the "
+               "effective sampler - and that half was already right";
+        EXPECT_EQ(Walk(), 0u) << "the widened shutter fires forever";
+    }
+
+    // BITS 6/7/8 UNDER A SEPARABLE PROGRAM PIPELINE. GetCurrentProgram() is null for the whole
+    // life of a bound pipeline, so all three shutters used to latch 0 and never move again
+    // after the first walk: glUseProgramStages would rebuild the composite and EmitShaderState
+    // would never be called, leaving the new composite with no ShaderCso handle at all.
+    TEST_F(TrackerWalk, ARestagedProgramPipelineFiresTheProgramBits) {
+        Vector<Uint> names;
+        Ctx().GenProgramPipelineNames(1, names);
+        ASSERT_EQ(names.size(), 1u);
+        Ctx().CreateProgramPipelineObject(names[0]);
+        Ctx().BindProgramPipelineObject(names[0]);
+        const auto& pipeline = Ctx().GetBoundProgramPipeline();
+        ASSERT_TRUE(pipeline != nullptr);
+        ASSERT_TRUE(Ctx().GetCurrentProgram() == nullptr)
+            << "the premise of this case is that the program family has no current program";
+
+        Walk();
+        ASSERT_EQ(Walk(), 0u) << "the fixture did not reach a steady state";
+
+        // What glUseProgramStages does at the end of its validation: one stage changes.
+        const Uint vertex = Ctx().CreateProgram();
+        pipeline->SetStageProgram(MobileGL::ShaderStage::Vertex, Ctx().GetProgramObject(vertex));
+        const Uint32 dirty = Walk();
+        EXPECT_NE(dirty & MGPipeDirtyBit(MGPipeDirty::NewShader), 0u)
+            << "the re-composited pipeline would never get a ShaderCso handle";
+        EXPECT_NE(dirty & MGPipeDirtyBit(MGPipeDirty::NewShaderBindings), 0u);
+        EXPECT_NE(dirty & MGPipeDirtyBit(MGPipeDirty::NewGlobalConstants), 0u)
+            << "set_global_constants would never be sent for a pipeline draw";
+        EXPECT_EQ(Walk(), 0u) << "the pipeline arm fires forever";
+    }
+
+    // The same three bits, moved by the OTHER event that changes what a pipeline draws: a
+    // stage program's relink. The stage set does not move at all here - only the link version
+    // the composite cache is keyed on, which is what makes GetProgramForDraw build a new one.
+    TEST_F(TrackerWalk, ARelinkOfAStageProgramFiresTheProgramBits) {
+        Vector<Uint> names;
+        Ctx().GenProgramPipelineNames(1, names);
+        ASSERT_EQ(names.size(), 1u);
+        Ctx().CreateProgramPipelineObject(names[0]);
+        Ctx().BindProgramPipelineObject(names[0]);
+        const auto& pipeline = Ctx().GetBoundProgramPipeline();
+        ASSERT_TRUE(pipeline != nullptr);
+
+        const Uint vertex = Ctx().CreateProgram();
+        const SharedPtr<MG_State::GLState::ProgramObject> stage = Ctx().GetProgramObject(vertex);
+        ASSERT_TRUE(stage != nullptr);
+        pipeline->SetStageProgram(MobileGL::ShaderStage::Vertex, stage);
+        Walk();
+        ASSERT_EQ(Walk(), 0u) << "the fixture did not reach a steady state";
+
+        // A real relink, through the entry point glLinkProgram drives. It fails - the
+        // program has no shaders attached - and that is deliberate: Link()'s PROLOGUE is where
+        // the link-observable versions are bumped, before any early-out, precisely so that
+        // every memo keyed on them reads stale from the instant the relink is enqueued.
+        stage->Link();
+        const Uint32 dirty = Walk();
+        EXPECT_NE(dirty & MGPipeDirtyBit(MGPipeDirty::NewShader), 0u);
+        EXPECT_NE(dirty & MGPipeDirtyBit(MGPipeDirty::NewShaderBindings), 0u);
+        EXPECT_NE(dirty & MGPipeDirtyBit(MGPipeDirty::NewGlobalConstants), 0u);
+        EXPECT_EQ(Walk(), 0u);
+    }
+
+    // AND THE HANDOVER, which is the shape an application actually writes: a program is in
+    // use, a pipeline is bound underneath it, and glUseProgram(0) hands the draw to the
+    // pipeline (GL 4.6 core 7.4). The program in use wins while there is one - so the bits
+    // must move when the SOURCE changes - and the pipeline must drive them afterwards.
+    TEST_F(TrackerWalk, UseProgramZeroLeavesTheBoundPipelineDrivingTheProgramBits) {
+        Vector<Uint> names;
+        Ctx().GenProgramPipelineNames(1, names);
+        ASSERT_EQ(names.size(), 1u);
+        Ctx().CreateProgramPipelineObject(names[0]);
+        Ctx().BindProgramPipelineObject(names[0]);
+        const auto& pipeline = Ctx().GetBoundProgramPipeline();
+        ASSERT_TRUE(pipeline != nullptr);
+
+        const Uint installed = Ctx().CreateProgram();
+        Ctx().UseProgram(installed);
+        ASSERT_TRUE(Ctx().GetCurrentProgram() != nullptr);
+        Walk();
+        ASSERT_EQ(Walk(), 0u) << "the fixture did not reach a steady state";
+
+        Ctx().UseProgram(0);
+        const Uint32 handover = Walk();
+        EXPECT_NE(handover & MGPipeDirtyBit(MGPipeDirty::NewShader), 0u)
+            << "the draw's program source changed and bit 6 did not fire";
+        ASSERT_EQ(Walk(), 0u);
+
+        // The pipeline is the source now, so a stage change has to reach the same bits.
+        const Uint vertex = Ctx().CreateProgram();
+        pipeline->SetStageProgram(MobileGL::ShaderStage::Vertex, Ctx().GetProgramObject(vertex));
+        const Uint32 dirty = Walk();
+        EXPECT_NE(dirty & MGPipeDirtyBit(MGPipeDirty::NewShader), 0u)
+            << "with no program in use the bound pipeline has to drive the program family";
+        EXPECT_NE(dirty & MGPipeDirtyBit(MGPipeDirty::NewShaderBindings), 0u);
+        EXPECT_NE(dirty & MGPipeDirtyBit(MGPipeDirty::NewGlobalConstants), 0u);
+    }
+
+    // P4a FABLE SEAM F-1. set_sampler_views is resolved for the PROGRAM IN USE (the sampler
+    // uniform's type picks which of a unit's targets is the view), and bit 12's shutter read
+    // only the texture-content aggregate and the bind generation - so `glUseProgram(P1); draw;
+    // glUseProgram(P2); draw` never re-emitted the set and the record went on describing P1's
+    // units. A program switch alone, with no bind and no texture change, has to fire it.
+    TEST_F(TrackerWalk, AProgramSwitchAloneFiresTheSamplerViewBit) {
+        const Uint first = Ctx().CreateProgram();
+        const Uint second = Ctx().CreateProgram();
+        Ctx().UseProgram(first);
+        Walk();
+        ASSERT_EQ(Walk(), 0u) << "the fixture did not reach a steady state";
+
+        Ctx().UseProgram(second);
+        const Uint32 dirty = Walk();
+        EXPECT_NE(dirty & MGPipeDirtyBit(MGPipeDirty::NewSamplerViews), 0u)
+            << "the view set is resolved for the program in use and a glUseProgram alone did not "
+               "re-emit it (F-1)";
+        EXPECT_EQ(Walk(), 0u) << "the widened shutter fires forever";
+    }
+
+    // The other input F-1 added: the params aggregate. SamplerEmit.h drops a unit's view to
+    // null when SamplesAsIncompleteTexture says so, and that predicate reads the effective
+    // sampler's filters and the level range - a glTexParameteri that completes a texture fired
+    // bit 13 and left the view entry null.
+    TEST_F(TrackerWalk, ATextureParameterAloneFiresTheSamplerViewBit) {
+        const auto& tex = Ctx().CreateTextureObject(1, TextureTarget::Texture2D);
+        ASSERT_TRUE(tex != nullptr);
+        Walk();
+        ASSERT_EQ(Walk(), 0u) << "the fixture did not reach a steady state";
+
+        tex->SetMaxLevel(4);
+        const Uint32 dirty = Walk();
+        EXPECT_NE(dirty & MGPipeDirtyBit(MGPipeDirty::NewSamplerViews), 0u)
+            << "completeness is a view-set input and a parameter change did not re-resolve it";
+        EXPECT_NE(dirty & MGPipeDirtyBit(MGPipeDirty::NewSamplers), 0u);
+        EXPECT_EQ(Walk(), 0u);
+    }
+
+    // P4a FABLE SEAM F-2 (and E's SD-4, which is this bit through a buffer image). Bit 14's
+    // plain-program arm mixed GetImageUnitVersion() ALONE - a per-program counter that two
+    // programs routinely share, 0 == 0 for any pair that never moved an image unit through
+    // glUniform1i - so a glUseProgram between them fired nothing and set_shader_images' window
+    // stayed the previous program's. The pipeline arm already mixed stageLinks; the plain arm
+    // now mixes the same identity bit 6 reads.
+    TEST_F(TrackerWalk, AProgramSwitchBetweenEqualImageUnitCountersFiresTheShaderImageBit) {
+        const Uint first = Ctx().CreateProgram();
+        const Uint second = Ctx().CreateProgram();
+        ASSERT_EQ(Ctx().GetProgramObject(first)->GetImageUnitVersion(),
+                  Ctx().GetProgramObject(second)->GetImageUnitVersion())
+            << "the premise of this case is two programs whose image-unit counters are equal";
+        Ctx().UseProgram(first);
+        Walk();
+        ASSERT_EQ(Walk(), 0u) << "the fixture did not reach a steady state";
+
+        Ctx().UseProgram(second);
+        const Uint32 dirty = Walk();
+        EXPECT_NE(dirty & MGPipeDirtyBit(MGPipeDirty::NewShaderImages), 0u)
+            << "set_shader_images' window is the program's and a glUseProgram alone did not "
+               "re-emit it (F-2)";
+        EXPECT_EQ(Walk(), 0u) << "the widened shutter fires forever";
+    }
+
     // ===================================================================================
     // set_vertex_attrib_defaults' payload (P2 brief D10)
     // ===================================================================================

MobileGL/MG_Test/Program/CMakeLists.txt

@@ -296,3 +296,26 @@ target_link_libraries(
 )
 
 gtest_discover_tests(ProgramArtifactsTest DISCOVERY_TIMEOUT 30 PROPERTIES LABELS unit)
+
+# P4a: the archive SERIALIZER over the same VisitFields tables, beside the header's own suite.
+# Its target and this registration are the CONTRACT commit's, like every other suite whose
+# contents a later package extends. Every case is a visible SKIP in a pull build, because the
+# codec is push-only - the root CMakeLists.txt appends it inside `if (MOBILEGL_PIPE_PUSH)` -
+# and a vanishing test would make `ctest -N` differ between the pull and push trees.
+add_executable(
+        ProgramArtifactsCodecTest
+        ProgramArtifactsCodecTest.cpp
+)
+
+target_include_directories(ProgramArtifactsCodecTest PRIVATE
+        ${MGL_ROOT}/include
+        ${MGL_ROOT}/MobileGL
+)
+
+target_link_libraries(
+        ProgramArtifactsCodecTest PRIVATE
+        GTest::gtest_main
+        ${LINK_LIBRARIES}
+)
+
+gtest_discover_tests(ProgramArtifactsCodecTest DISCOVERY_TIMEOUT 30 PROPERTIES LABELS unit)

MobileGL/MG_Test/Program/ProgramArtifactsCodecTest.cpp

@@ -0,0 +1,375 @@
+// MobileGL - MobileGL/MG_Test/Program/ProgramArtifactsCodecTest.cpp
+// Copyright (c) 2025-2026 MobileGL-Dev
+// Licensed under the GNU Lesser General Public License v3.0:
+//   https://www.gnu.org/licenses/gpl-3.0.txt
+//   https://www.gnu.org/licenses/lgpl-3.0.txt
+// SPDX-License-Identifier: LGPL-3.0-only
+// End of Source File Header
+
+// The reflection ARCHIVE's serializer (P4a): create_shader_state's payload is per-stage SPIR-V
+// plus LinkArtifacts + SpirvArtifacts, whole structs, and the codec is what turns them into
+// bytes. In monolith it is never called on the hot path - the two structs ride beside the
+// record through the apply entry point's companion pointers - so THIS SUITE plus the verify
+// lane's round trip are the only things that exercise it until a transport exists.
+//
+// WHAT IT HAS TO PIN, and each of the three is a different failure:
+//   * a fully populated archive survives a round trip FIELD BY FIELD, including both of
+//     XfbVarying's spellings (the GL name AND the block instance / member / element triple)
+//     and every one of TypeFacts' twenty members - a codec that dropped one would be invisible
+//     until a backend read a reflection answer that had quietly become zero;
+//   * a TRUNCATED stream is refused rather than guessed at;
+//   * a VERSION or struct-size mismatch is refused rather than deserialised into a layout this
+//     build does not have.
+//
+// AND ONE PROPERTY THAT IS NOT ABOUT BYTES AT ALL: LinkArtifacts has 58 members and its
+// VisitFields table visits 57. The 58th is the live SharedPtr<glslang::TProgram>, which is
+// null for every archived instance by construction and points into an arena no archive owns.
+// The codec has no arm for it, and the count is asserted here because that is the only place
+// it can be: VisitFields needs an instance, and these structs carry strings, vectors and maps,
+// so no static_assert can walk them.
+//
+// Every case is a visible SKIP in a pull build rather than a vanishing test, so `ctest -N`
+// stays name-for-name identical between the pull and the push trees.
+
+#include <gtest/gtest.h>
+
+#include "Includes.h"
+#if MOBILEGL_PIPE_PUSH
+#include <MG_State/GLState/ProgramState/ProgramArtifactsCodec.h>
+#endif
+
+using namespace MobileGL;
+#if MOBILEGL_PIPE_PUSH
+using namespace MobileGL::MG_State::GLState;
+
+namespace {
+    TypeFacts MakeTypeFacts() {
+        // Every member set to something that is NOT its default, so a field the codec skips
+        // reads back as the default and the comparison names it.
+        TypeFacts facts{};
+        facts.isArray = true;
+        facts.isSizedArray = true;
+        facts.isMatrix = true;
+        facts.isVector = true;
+        facts.isOpaque = true;
+        facts.isTexture = true;
+        facts.isImage = true;
+        facts.isDouble = true;
+        facts.isVoid = true;
+        facts.isBuffer = true;
+        facts.isPatch = true;
+        facts.hasIndex = true;
+        facts.hasFormat = true;
+        facts.vectorSize = 3;
+        facts.matrixCols = 4;
+        facts.matrixRows = 2;
+        facts.layoutIndex = 7;
+        facts.layoutFormat = 0x8814u;
+        facts.layoutMatrix = 1;
+        facts.basicType = 11;
+        return facts;
+    }
+
+    ResourceReflection MakeReflection(const char* name, Int location) {
+        ResourceReflection reflection{};
+        reflection.name = name;
+        reflection.glDefineType = GL_FLOAT_VEC4;
+        reflection.offset = 16;
+        reflection.size = 4;
+        reflection.index = 2;
+        reflection.counterIndex = 3;
+        reflection.arrayStride = 16;
+        reflection.topLevelArraySize = 5;
+        reflection.topLevelArrayStride = 32;
+        reflection.binding = 6;
+        reflection.location = location;
+        reflection.stages = 0x3u;
+        reflection.arraySize = 8;
+        reflection.type = MakeTypeFacts();
+        return reflection;
+    }
+
+    XfbVarying MakeXfbVarying() {
+        XfbVarying varying{};
+        // BOTH SPELLINGS. `name` is the GL one ("Block.member"), which the interface queries
+        // and the ESSL driver-side capture list need; the triple below is what a SPIR-V
+        // backend needs instead, because the decoration target is the block's instance
+        // variable and the member index inside it.
+        varying.name = "Captured.position";
+        varying.type = GL_FLOAT_VEC3;
+        varying.size = 2;
+        varying.bufferIndex = 1;
+        varying.offsetBytes = 12;
+        varying.byteSize = 24;
+        varying.packedOffsetBytes = 8;
+        varying.blockInstanceName = "capturedInstance";
+        varying.blockName = "Captured";
+        varying.blockMemberIndex = 1;
+        varying.blockMemberElement = 3;
+        return varying;
+    }
+
+    LinkArtifacts MakeLinkArtifacts() {
+        LinkArtifacts link{};
+        link.uniformReflection = {MakeReflection("uColour", 0), MakeReflection("uMatrix", 1)};
+        link.blockReflection = {MakeReflection("Block", -1)};
+        link.pipeInputReflection = {MakeReflection("inPosition", 0)};
+        link.pipeOutputReflection = {MakeReflection("outColour", 0)};
+        link.lastStageIsFragment = true;
+        link.computeLocalSize = {8u, 4u, 2u};
+        link.uniformIndexByName = {{"uColour", 0}, {"uMatrix", 1}};
+        link.attribs = {"inPosition", "inNormal"};
+        link.attribTypes = {GL_FLOAT_VEC3, GL_FLOAT_VEC3};
+        link.linkedFragDataLocation = {{"outColour", 0u}};
+        link.linkedFragDataIndex = {{"outColour", 1u}};
+        link.glUniformIndexToTProgram = {0, 1};
+        link.tProgramUniformIndexToGl = {0, 1};
+        link.glBlockIndexToTProgram = {0};
+        link.tProgramBlockIndexToGl = {-1};
+        link.glUniformBlockIndexToBlock = {0};
+        link.blockIndexToGlUniformBlock = {0};
+        link.linkedExplicitUniformLocations = {{"uColour", 3}};
+        link.uniformLocations = {{"uColour", 0u}, {"uMatrix", 4u}};
+        link.writtenUniformLocationBits = {0x5ull};
+        link.writtenUniformIndexBits = {0x3ull};
+        link.writtenUniformIndices = {0u, 1u};
+        link.uniformIndexInTProgram = {0, 1};
+        link.uniformSamplerOrImageUnitIndex = {-1, 2};
+        link.explicitOpaqueUniformBindings = {{"uSampler", 5u}};
+        link.uniformBlockIndexByName = {{"Block", 0u}};
+        link.uniformBlockBinding = {2};
+        link.shaderStorageBlockBinding = {{"Storage", 1}};
+        link.storageBlocksWithoutBinding = {"Storage"};
+        link.uniformBlocksWithoutBinding = {"Block"};
+        link.activeUniformCount = 2u;
+        link.usesReservedNumSamples = true;
+        link.maxUniformLocation = 4u;
+        link.uniformNameMaxLength = 9;
+        link.attribInNameMaxLength = 11;
+        link.uniformBlockNameMaxLength = 6;
+        link.infoLog = "linked with warnings";
+        link.linkStatus = true;
+        link.xfbVaryings = {MakeXfbVarying()};
+        link.xfbInterfaceNames = {"gl_NextBuffer", "Captured.position"};
+        link.xfbStrides = {32u, 0u};
+        link.gsStripTriangles = {3u, 5u};
+        link.gsStripCaptureFixup = true;
+        link.gsInputPrimitive = GL_TRIANGLES;
+        link.tcsOutputVertices = 3;
+        link.gsOutputPrimitive = GL_TRIANGLE_STRIP;
+        link.gsMaxVertices = 12;
+        link.gsInvocations = 2;
+        link.tessGenMode = GL_QUADS;
+        link.tessGenSpacing = GL_FRACTIONAL_ODD;
+        link.tessGenVertexOrder = GL_CW;
+        link.tessGenPointMode = true;
+        link.xfbBufferMode = GL_SEPARATE_ATTRIBS;
+        link.xfbVaryingNameMaxLength = 18;
+        link.xfbNeedsScatteredCapture = true;
+        link.xfbPackedStride = 24u;
+
+        // The one glslang-typed member that DOES travel: a plain aggregate of a string,
+        // scalars and two vectors. The codec has a hand-written arm for it because
+        // ProgramArtifacts.h gives it no VisitFields table.
+        glslang::TIntermediate::TUniformInitializer initializer;
+        initializer.name = "uInitialised";
+        initializer.basicType = glslang::EbtInt;
+        initializer.vectorSize = 2;
+        initializer.matrixCols = 0;
+        initializer.matrixRows = 0;
+        initializer.arraySize = 3;
+        initializer.intValues = {1, 2, 3, 4, 5, 6};
+        initializer.floatValues = {};
+        link.uniformInitialValues.push_back(initializer);
+        return link;
+    }
+
+    SpirvArtifacts MakeSpirvArtifacts() {
+        SpirvArtifacts spirv{};
+        spirv.generatedSpirv = {{0x07230203u, 0x00010300u, 0u}, {0x07230203u, 0x00010300u, 1u}};
+        spirv.enableSpirvValidation = true;
+        spirv.uniformOffsets = {0u, 16u, kInvalidUniformOffset};
+        spirv.globalUboScratch = {1, 2, 3, 4, 5, 6, 7, 8};
+        spirv.reservedNumSamplesOffset = 32u;
+        spirv.spirvStatus = true;
+        spirv.nativeFloat64 = true;
+        spirv.pointSizeDemoted = true;
+        return spirv;
+    }
+} // namespace
+#endif // MOBILEGL_PIPE_PUSH
+
+// The round trip, field by field. A re-encode equality alone would prove the codec is
+// self-consistent and nothing else - a field it skips in BOTH directions round-trips
+// perfectly - so the members are read back explicitly first, and the byte comparison is the
+// catch-all underneath them.
+TEST(ProgramArtifactsCodec, RoundTripsAFullyPopulatedArchive) {
+#if MOBILEGL_PIPE_PUSH
+    const LinkArtifacts link = MakeLinkArtifacts();
+    const SpirvArtifacts spirv = MakeSpirvArtifacts();
+
+    Vector<Uint8> bytes;
+    EncodeProgramArtifacts(link, spirv, bytes);
+    ASSERT_FALSE(bytes.empty());
+
+    LinkArtifacts decodedLink;
+    SpirvArtifacts decodedSpirv;
+    ASSERT_TRUE(DecodeProgramArtifacts(bytes.data(), bytes.size(), decodedLink, decodedSpirv));
+
+    // The four reflection vectors, with their TypeFacts.
+    ASSERT_EQ(decodedLink.uniformReflection.size(), 2u);
+    EXPECT_EQ(decodedLink.uniformReflection[0].name, "uColour");
+    EXPECT_EQ(decodedLink.uniformReflection[1].location, 1);
+    EXPECT_EQ(decodedLink.uniformReflection[0].arrayStride, 16);
+    EXPECT_EQ(decodedLink.uniformReflection[0].stages, 0x3u);
+    EXPECT_TRUE(decodedLink.uniformReflection[0].type.isSizedArray);
+    EXPECT_EQ(decodedLink.uniformReflection[0].type.matrixCols, 4);
+    EXPECT_EQ(decodedLink.uniformReflection[0].type.layoutFormat, 0x8814u);
+    EXPECT_EQ(decodedLink.uniformReflection[0].type.basicType, 11);
+    ASSERT_EQ(decodedLink.blockReflection.size(), 1u);
+    ASSERT_EQ(decodedLink.pipeInputReflection.size(), 1u);
+    ASSERT_EQ(decodedLink.pipeOutputReflection.size(), 1u);
+
+    // BOTH XfbVarying SPELLINGS.
+    ASSERT_EQ(decodedLink.xfbVaryings.size(), 1u);
+    EXPECT_EQ(decodedLink.xfbVaryings[0].name, "Captured.position");
+    EXPECT_EQ(decodedLink.xfbVaryings[0].blockInstanceName, "capturedInstance");
+    EXPECT_EQ(decodedLink.xfbVaryings[0].blockName, "Captured");
+    EXPECT_EQ(decodedLink.xfbVaryings[0].blockMemberIndex, 1);
+    EXPECT_EQ(decodedLink.xfbVaryings[0].blockMemberElement, 3);
+    EXPECT_EQ(decodedLink.xfbVaryings[0].packedOffsetBytes, 8u);
+
+    // The maps, the set and the fixed array - the four container shapes the archive is made
+    // of, each with a reader that has to agree with its writer about the length prefix.
+    EXPECT_EQ(decodedLink.uniformIndexByName.size(), 2u);
+    EXPECT_EQ(decodedLink.uniformIndexByName.at("uMatrix"), 1);
+    EXPECT_EQ(decodedLink.shaderStorageBlockBinding.at("Storage"), 1);
+    EXPECT_EQ(decodedLink.storageBlocksWithoutBinding.count("Storage"), 1u);
+    EXPECT_EQ(decodedLink.uniformBlocksWithoutBinding.count("Block"), 1u);
+    EXPECT_EQ(decodedLink.computeLocalSize[0], 8u);
+    EXPECT_EQ(decodedLink.computeLocalSize[2], 2u);
+
+    // The glslang-typed aggregate, through the codec's one hand-written arm.
+    ASSERT_EQ(decodedLink.uniformInitialValues.size(), 1u);
+    EXPECT_EQ(decodedLink.uniformInitialValues[0].name, "uInitialised");
+    EXPECT_EQ(decodedLink.uniformInitialValues[0].basicType, glslang::EbtInt);
+    EXPECT_EQ(decodedLink.uniformInitialValues[0].arraySize, 3);
+    ASSERT_EQ(decodedLink.uniformInitialValues[0].intValues.size(), 6u);
+    EXPECT_EQ(decodedLink.uniformInitialValues[0].intValues[5], 6);
+    EXPECT_TRUE(decodedLink.uniformInitialValues[0].floatValues.empty());
+
+    // The scalars at the tail, which is where a length-prefix that drifted by one would first
+    // read as garbage rather than as a short read.
+    EXPECT_EQ(decodedLink.infoLog, "linked with warnings");
+    EXPECT_TRUE(decodedLink.linkStatus);
+    EXPECT_EQ(decodedLink.tessGenSpacing, static_cast<GLenum>(GL_FRACTIONAL_ODD));
+    EXPECT_TRUE(decodedLink.tessGenPointMode);
+    EXPECT_EQ(decodedLink.xfbPackedStride, 24u);
+
+    // SpirvArtifacts, including the nested vector of SPIR-V words and the sentinel offset.
+    ASSERT_EQ(decodedSpirv.generatedSpirv.size(), 2u);
+    ASSERT_EQ(decodedSpirv.generatedSpirv[0].size(), 3u);
+    EXPECT_EQ(decodedSpirv.generatedSpirv[1][2], 1u);
+    ASSERT_EQ(decodedSpirv.uniformOffsets.size(), 3u);
+    EXPECT_EQ(decodedSpirv.uniformOffsets[2], kInvalidUniformOffset);
+    EXPECT_EQ(decodedSpirv.globalUboScratch.size(), 8u);
+    EXPECT_EQ(decodedSpirv.reservedNumSamplesOffset, 32u);
+    EXPECT_TRUE(decodedSpirv.nativeFloat64);
+    EXPECT_TRUE(decodedSpirv.pointSizeDemoted);
+
+    // THE LIVE TProgram IS NEVER CARRIED and never reconstructed.
+    EXPECT_EQ(decodedLink.program, nullptr);
+
+    // The catch-all: re-encoding what came back has to produce the same bytes, which covers
+    // every member the explicit reads above do not name.
+    Vector<Uint8> reencoded;
+    EncodeProgramArtifacts(decodedLink, decodedSpirv, reencoded);
+    EXPECT_EQ(reencoded, bytes);
+#else
+    GTEST_SKIP() << "MOBILEGL_PIPE_PUSH is off: the archive codec is push-only";
+#endif
+}
+
+// Negative control 1. Every prefix length is checked against the bytes that REMAIN, so a
+// stream cut anywhere has to come back false with both outputs defaulted - never a partially
+// filled archive, and never a resize driven by a count the stream cannot back.
+TEST(ProgramArtifactsCodec, ATruncatedStreamIsRefusedNotGuessed) {
+#if MOBILEGL_PIPE_PUSH
+    Vector<Uint8> bytes;
+    EncodeProgramArtifacts(MakeLinkArtifacts(), MakeSpirvArtifacts(), bytes);
+    ASSERT_GT(bytes.size(), 64u);
+
+    // Cut at a spread of points rather than one: the header, a length prefix, the middle of a
+    // string and the last byte all fail through different branches.
+    for (const SizeT cut : {SizeT{0}, SizeT{4}, SizeT{9}, bytes.size() / 3, bytes.size() / 2,
+                            bytes.size() - 1}) {
+        LinkArtifacts link;
+        SpirvArtifacts spirv;
+        link.infoLog = "must be cleared";
+        EXPECT_FALSE(DecodeProgramArtifacts(bytes.data(), cut, link, spirv))
+            << "a stream truncated at " << cut << " was accepted";
+        EXPECT_TRUE(link.infoLog.empty()) << "a refused decode left the output half-filled";
+        EXPECT_TRUE(link.uniformReflection.empty());
+        EXPECT_TRUE(spirv.generatedSpirv.empty());
+    }
+
+    // And TRAILING bytes are a mismatch too: the format accounts for every byte it writes, so
+    // anything left over means the reader and the writer disagree about the shape.
+    Vector<Uint8> withTail = bytes;
+    withTail.push_back(0);
+    LinkArtifacts link;
+    SpirvArtifacts spirv;
+    EXPECT_FALSE(DecodeProgramArtifacts(withTail.data(), withTail.size(), link, spirv));
+#else
+    GTEST_SKIP() << "MOBILEGL_PIPE_PUSH is off: the archive codec is push-only";
+#endif
+}
+
+// Negative control 2. The version word and the struct-size echo are the two things a compiler
+// cannot check: a struct that gained a field and a codec that did not would otherwise
+// deserialise garbage into the tail of a reflection table. Both have to REFUSE.
+TEST(ProgramArtifactsCodec, AVersionMismatchIsRefused) {
+#if MOBILEGL_PIPE_PUSH
+    Vector<Uint8> bytes;
+    EncodeProgramArtifacts(MakeLinkArtifacts(), MakeSpirvArtifacts(), bytes);
+    ASSERT_GT(bytes.size(), 12u);
+
+    LinkArtifacts link;
+    SpirvArtifacts spirv;
+    ASSERT_TRUE(DecodeProgramArtifacts(bytes.data(), bytes.size(), link, spirv));
+
+    // The version word first: a reader that saw a format it does not know must not try to
+    // guess the layout.
+    Vector<Uint8> wrongVersion = bytes;
+    ++wrongVersion[0];
+    EXPECT_FALSE(DecodeProgramArtifacts(wrongVersion.data(), wrongVersion.size(), link, spirv));
+
+    // Then the MGL_LINKARTIFACTS_SIZE echo, which is the half that catches a struct that grew
+    // under a codec that did not - the failure the four sizeof trip wires in
+    // ProgramArtifacts.h send an author here to fix.
+    Vector<Uint8> wrongSize = bytes;
+    ++wrongSize[4];
+    EXPECT_FALSE(DecodeProgramArtifacts(wrongSize.data(), wrongSize.size(), link, spirv));
+
+    // A null pointer is refused rather than dereferenced.
+    EXPECT_FALSE(DecodeProgramArtifacts(nullptr, 0, link, spirv));
+#else
+    GTEST_SKIP() << "MOBILEGL_PIPE_PUSH is off: the archive codec is push-only";
+#endif
+}
+
+// The codec walks the VisitFields tables and nothing else, so what those tables visit IS the
+// archive. LinkArtifacts has 58 members and its table visits 57: the 58th is the live glslang
+// TProgram, which is null for every archived instance by construction and points into an arena
+// no archive owns. A codec arm for it would be a use-after-free waiting for a cache hit.
+TEST(ProgramArtifactsCodec, TheTablesVisitEveryMemberExceptTheLiveProgram) {
+#if MOBILEGL_PIPE_PUSH
+    EXPECT_EQ(ProgramArtifactsVisitedFieldCount<LinkArtifacts>(), 57u);
+    EXPECT_EQ(ProgramArtifactsVisitedFieldCount<SpirvArtifacts>(), 8u);
+    EXPECT_EQ(ProgramArtifactsVisitedFieldCount<ResourceReflection>(), 14u);
+    EXPECT_EQ(ProgramArtifactsVisitedFieldCount<XfbVarying>(), 11u);
+    EXPECT_EQ(ProgramArtifactsVisitedFieldCount<TypeFacts>(), 20u);
+#else
+    GTEST_SKIP() << "MOBILEGL_PIPE_PUSH is off: the archive codec is push-only";
+#endif
+}

MobileGL/MG_Test/SanityTest.cpp

@@ -3129,6 +3129,177 @@ TEST(DirectGLESTextureSync, UnitMemoRefusesToDriveATwinFromAnotherTexture) {
     MG_Impl::GLImpl::BindTexture(GL_TEXTURE_2D, 0);
 }
 
+namespace {
+    // What glTexParameteri actually reached the driver, and which backend texture was bound
+    // when it did. The G9 probe below is a WHITE-BOX assertion (ID-19): the parameter push is
+    // not observable through public GL without creating the very sampler view whose absence is
+    // the subject, so the observation is taken at the driver boundary instead.
+    struct TexParamCall {
+        GLuint texture;
+        GLenum pname;
+        GLint value;
+    };
+    MobileGL::Vector<TexParamCall>* g_texParamCalls = nullptr;
+    GLuint g_texParamBoundTexture = 0;
+
+    void TP_BindTexture(GLenum, GLuint texture) { g_texParamBoundTexture = texture; }
+    void TP_ActiveTexture(GLenum) {}
+    void TP_TexParameteri(GLenum, GLenum pname, GLint value) {
+        if (g_texParamCalls) {
+            g_texParamCalls->push_back({g_texParamBoundTexture, pname, value});
+        }
+    }
+    void TP_TexParameterf(GLenum, GLenum, GLfloat) {}
+    void TP_TexParameterfv(GLenum, GLenum, const GLfloat*) {}
+    void TP_PixelStorei(GLenum, GLint) {}
+    void TP_BindBuffer(GLenum, GLuint) {}
+
+    struct ScopedTexParamRecording {
+        explicit ScopedTexParamRecording(MobileGL::Vector<TexParamCall>& sink) {
+            g_texParamCalls = &sink;
+            g_texParamBoundTexture = 0;
+        }
+        ~ScopedTexParamRecording() { g_texParamCalls = nullptr; }
+        ScopedTexParamRecording(const ScopedTexParamRecording&) = delete;
+        ScopedTexParamRecording& operator=(const ScopedTexParamRecording&) = delete;
+    };
+} // namespace
+
+// G9 AS A WHITE-BOX ASSERTION (gates review R1, ID-19), AND IT COVERS THE HALF THE PUBLIC-GL
+// SCENARIO CANNOT.
+//
+// TextureParamsWithoutASamplerViewScenario catches "the parameters were EMITTED and marked
+// synced but never applied": its observation is a sample, the sample creates the sampler view,
+// and IsDrawSyncClean then skips the sync. What it cannot catch is a backend that merely DEFERS
+// the apply to the first sampler view - the observation creates that view, the parameters land
+// at that moment, and the case is green. Here the reading is taken while the texture is still
+// attachment-only: nothing is ever bound to a unit, no sampler view is minted, and the
+// assertion is that the parameter reached the driver ANYWAY.
+//
+// RED ON THE PRE-P4a BEHAVIOUR: with set_texture_params addressed by resource, this twin's
+// parameter push no longer needs anything to be bound. A backend that reinstated the deferral -
+// resolving the params through a sampler view, or gating the push on a unit binding - leaves
+// the recording empty and this case fails, which is exactly the regression the scenario's
+// self-repair hides.
+//
+// WHAT IT DOES NOT COVER, AND THE NEXT READER MUST NOT OVER-TRUST IT (review N-9): the probe
+// drives SyncTextureParamsToBackend DIRECTLY, so the only deferral shape it can see is one
+// INSIDE that function. A regression that gates the CALL on a sampler view existing - in
+// SyncNeccessaryTextures, or in package E's per-unit walk - leaves this case green. That
+// caller-level half is a scenario's job and the scenario is package F's (G9's scenario half,
+// gates review R1); this is the backend-side probe R1 asked for and nothing wider.
+TEST(DirectGLESTextureSync, AnAttachmentOnlyTexturesParametersReachTheDriverWithNoSamplerView) {
+    using namespace MobileGL;
+    ScopedDirectGLESTextureBindings scoped; // fresh GLContext + registry + binding caches
+    Vector<TexParamCall> params;
+    ScopedTexParamRecording recording(params);
+
+    auto functions = MG_Backend::DirectGLES::g_GLESFuncs;
+    functions.glBindTexture = TP_BindTexture;
+    functions.glActiveTexture = TP_ActiveTexture;
+    functions.glTexParameteri = TP_TexParameteri;
+    functions.glTexParameterf = TP_TexParameterf;
+    functions.glTexParameterfv = TP_TexParameterfv;
+    functions.glPixelStorei = TP_PixelStorei;
+    functions.glBindBuffer = TP_BindBuffer;
+    MG_Backend::DirectGLES::SetGLESFuncsTable(functions);
+
+    GLuint name = 0;
+    MG_Impl::GLImpl::GenTextures(1, &name);
+    const auto texture = MakeComplete2DTexture(name, 8);
+    ASSERT_NE(texture, nullptr);
+    // ATTACHMENT-ONLY from here on: the unit that specified it is released, so nothing in this
+    // test ever binds this texture for sampling and nothing mints a sampler view for it.
+    MG_Impl::GLImpl::BindTexture(GL_TEXTURE_2D, 0);
+
+    // The parameter that has to travel. Red -> Green is not any texture's default, so a driver
+    // that never hears about it is distinguishable from one that does.
+    texture->SetSwizzleParam(TextureSwizzleParam::Red, TextureSwizzleParam::Green);
+
+    auto& registry = MG_Backend::DirectGLES::TextureImpl::g_backendTextureObjects;
+    auto& twin = registry.GetOrCreate(texture);
+    if (!twin) {
+        twin = MakeShared<MG_Backend::DirectGLES::TextureImpl::BackendTextureObject>();
+    }
+    ASSERT_NE(twin, nullptr);
+
+#if MOBILEGL_PIPE_PUSH
+    const MG_Pipe::MGPipeHandle res = registry.HandleOf(texture.get());
+    MG_Pipe::MGPipeHandle builtinSampler = MG_Pipe::kMGPipeNullHandle;
+    if (MG_Backend::DirectGLES::TextureResourceSubsystemEnabled()) {
+        // The handle arm reads the applier, so the applier is what this probe writes - which is
+        // also what makes it a white-box test rather than a scenario: no client emitter exists
+        // on this tree, and the point is Espryt's behaviour given a record, not the client's.
+        ASSERT_FALSE(MG_Pipe::MGPipeHandleIsNull(res));
+        MG_Pipe::MGPResourceDesc desc{};
+        desc.Resource = res;
+        desc.Target = static_cast<Uint8>(MG_Pipe::MGPipeResourceTarget::Tex2D);
+        desc.StorageKind = static_cast<Uint8>(TextureStorageType::Mipmap);
+        desc.InternalFormat = static_cast<Uint32>(TextureInternalFormat::RGBA8);
+        desc.Width = 8;
+        desc.Height = 8;
+        desc.Depth = 1;
+        desc.ArrayLayers = 1;
+        desc.Levels = 1;
+        EXPECT_TRUE(MG_Pipe::MGPipeApplyResourceCreate(desc));
+
+        // Every ITextureObject owns a sampler object, so the built-in sampler CSO is not
+        // optional (a null one is Fatal{ProtocolCorruption} in the applier). It is a SAMPLER
+        // CSO and not a sampler VIEW - the distinction this case exists for.
+        auto samplerOwner = MakeShared<MG_State::GLState::SamplerObject>(0u);
+        builtinSampler = MG_Pipe::MGPipeSlots().Acquire(MG_Pipe::MGPipeKind::SamplerCso,
+                                                        samplerOwner->GetLifetimeId());
+        ASSERT_FALSE(MG_Pipe::MGPipeHandleIsNull(builtinSampler));
+        MG_Pipe::MGPSamplerDesc samplerDesc{};
+        samplerDesc.Cso = builtinSampler;
+        SamplerParameters samplerParams{};
+        MG_Pipe::MGPipeApplyCreateSamplerState(samplerDesc, &samplerParams);
+
+        MG_Pipe::MGPTextureParams pushed{};
+        pushed.Res = res;
+        pushed.BuiltinSampler = builtinSampler;
+        pushed.MaxLevel = 0;
+        pushed.Swizzle[0] = static_cast<Uint8>(TextureSwizzleParam::Green);
+        pushed.Swizzle[1] = static_cast<Uint8>(TextureSwizzleParam::Green);
+        pushed.Swizzle[2] = static_cast<Uint8>(TextureSwizzleParam::Blue);
+        pushed.Swizzle[3] = static_cast<Uint8>(TextureSwizzleParam::Alpha);
+        MG_Pipe::MGPipeApplySetTextureParams(pushed);
+
+        // THE OBSERVATION IS TAKEN WHILE THE TEXTURE IS STILL ATTACHMENT-ONLY: no sampler view
+        // record exists, and no sampler-view twin does either. This is the assertion the public
+        // scenario cannot make, because making it there would create the view.
+        EXPECT_EQ(MG_Backend::DirectGLES::SamplerViewImpl::g_backendSamplerViews.FindByHandle(
+                      MG_Pipe::MGPipeSlots().FindByLifetimeId(MG_Pipe::MGPipeKind::SamplerViewCso,
+                                                              texture->GetLifetimeId())),
+                  nullptr)
+            << "a sampler view was minted for a texture nothing sampled";
+    }
+#endif
+
+    const SizeT before = params.size();
+    twin->SyncTextureParamsToBackend(texture);
+
+    Bool sawSwizzleR = false;
+    for (SizeT i = before; i < params.size(); ++i) {
+        if (params[i].pname == GL_TEXTURE_SWIZZLE_R) {
+            sawSwizzleR = true;
+            EXPECT_EQ(params[i].value, static_cast<GLint>(GL_GREEN))
+                << "the swizzle reached the driver with the wrong value";
+        }
+    }
+    EXPECT_TRUE(sawSwizzleR)
+        << "an attachment-only texture's GL_TEXTURE_SWIZZLE_R never reached the driver: the "
+           "parameter push is gated on something being bound, which is the deferral G9's public "
+           "scenario cannot observe";
+
+#if MOBILEGL_PIPE_PUSH
+    if (!MG_Pipe::MGPipeHandleIsNull(builtinSampler)) {
+        MG_Pipe::MGPipeApplyDeleteSamplerState(MG_Pipe::MGPHandleOnly{builtinSampler});
+        MG_Pipe::MGPipeSlots().Free(MG_Pipe::MGPipeKind::SamplerCso, builtinSampler);
+    }
+#endif
+}
+
 TEST(DirectVulkanSanity, GraphicsSamplerFeedbackOnlyAliasesWritableOverlappingMip) {
     using MobileGL::MG_Backend::DirectVulkan::UniformManager;
 
@@ -3954,6 +4125,238 @@ TEST(DirectGLESSlotTable, EverySwitchedOverKindResolvesItsTwinThroughTheHandleAr
         table.ReleaseByHandle(second);
         MG_Pipe::MGPipeSlots().Free(MG_Pipe::MGPipeKind::Buffer, second);
     }
+
+    // P4a: the EIGHTH table and the SIXTH kind - the sampler view, which is the only kind in
+    // the phase with no frontend object at all. MobileGL has no sampler-view class: GL binds a
+    // texture to a unit and the sampler uniform's type plus the two completeness predicates
+    // decide what the shader sees, gallium's one-view-per-slot IS that resolved form, and the
+    // resolution moves to the CLIENT (D-F3). So this table is handle-keyed only, like the
+    // buffer resource table above, and its twin owns no driver id whatsoever - what it holds is
+    // the server's memo of one resolved view plus the raw-depth-fetch substitution decision,
+    // which is one of the two backend post-processings ARCHITECTURE.md:206 keeps on the server.
+    //
+    // The handle is minted off the TEXTURE's lifetime id (D-F2: one view per ITextureObject),
+    // which is what makes HandleOf resolve at all - and it is legal precisely because the two
+    // kinds have separate slot spaces, so the same lifetime id names a Texture slot and a
+    // SamplerViewCso slot without either shadowing the other.
+    {
+        using MobileGL::MG_Backend::DirectGLES::SamplerViewImpl::g_backendSamplerViews;
+        using MobileGL::MG_Backend::DirectGLES::SamplerViewImpl::BackendSamplerViewObject;
+        auto& table = g_backendSamplerViews;
+
+        SharedPtr<ITextureObject> owner = MakeShared<TextureObject2D>(0u);
+        const MG_Pipe::MGPipeHandle first =
+            MG_Pipe::MGPipeSlots().Acquire(MG_Pipe::MGPipeKind::SamplerViewCso, owner->GetLifetimeId());
+        ASSERT_FALSE(MG_Pipe::MGPipeHandleIsNull(first))
+            << "SamplerViewCso: the client allocator minted no handle for a live texture's view";
+
+        // The same lifetime id, two kinds, two independent slot spaces.
+        const MG_Pipe::MGPipeHandle textureHandle =
+            MG_Pipe::MGPipeSlots().FindByLifetimeId(MG_Pipe::MGPipeKind::Texture, owner->GetLifetimeId());
+        EXPECT_FALSE(first == textureHandle)
+            << "SamplerViewCso: the view handle and the texture handle are the same {slot, gen}, so "
+               "one kind's slot space is aliasing the other's";
+
+        auto& firstTwin = table.GetOrCreate(first);
+        firstTwin = MakeShared<BackendSamplerViewObject>();
+        firstTwin->SyncedSerial = 0xABCDEFull;
+        const BackendSamplerViewObject* const firstRaw = firstTwin.get();
+        EXPECT_EQ(table.FindByHandle(first), &firstTwin)
+            << "SamplerViewCso: the handle does not address the twin GetOrCreate handed back";
+        EXPECT_EQ(table.HandleOf(owner.get()), first)
+            << "SamplerViewCso: HandleOf did not resolve the view minted off this texture's "
+               "lifetime id, so a backend path that still arrives holding the object cannot find "
+               "its view";
+
+        const SharedPtr<BackendSamplerViewObject> released = table.ReleaseByHandle(first);
+        EXPECT_NE(released, nullptr) << "SamplerViewCso: delete_sampler_view found no twin to retire";
+        EXPECT_EQ(table.FindByHandle(first), nullptr)
+            << "SamplerViewCso: the twin outlived its delete_sampler_view";
+        MG_Pipe::MGPipeSlots().Free(MG_Pipe::MGPipeKind::SamplerViewCso, first);
+
+        auto successorOwner = MakeShared<TextureObject2D>(0u);
+        const MG_Pipe::MGPipeHandle second = MG_Pipe::MGPipeSlots().Acquire(
+            MG_Pipe::MGPipeKind::SamplerViewCso, successorOwner->GetLifetimeId());
+        ASSERT_FALSE(MG_Pipe::MGPipeHandleIsNull(second)) << "SamplerViewCso";
+        EXPECT_EQ(second.Slot, first.Slot)
+            << "SamplerViewCso: the freed slot was not handed back, so this walk did not exercise "
+               "the recycle it exists to test";
+        EXPECT_NE(second.Gen, first.Gen)
+            << "SamplerViewCso: Gen did not move on slot reuse - the predecessor's handle would "
+               "resolve to the successor's view, which is the ABA the {slot, gen} key exists to stop";
+        EXPECT_EQ(table.FindByHandle(first), nullptr) << "SamplerViewCso: the STALE handle resolved";
+
+        auto& secondTwin = table.GetOrCreate(second);
+        EXPECT_EQ(secondTwin, nullptr)
+            << "SamplerViewCso: a view at a recycled slot inherited its predecessor's memo, so the "
+               "raw-depth-fetch decision of a dead texture would be replayed for a live one";
+        secondTwin = MakeShared<BackendSamplerViewObject>();
+        EXPECT_NE(table.FindByHandle(second)->get(), firstRaw) << "SamplerViewCso";
+
+        // BACKWARD generations are REFUSED rather than adopted, exactly as they are on every
+        // other handle-keyed table (SlotTables.h:301-321). Forward is a recycle; adopting a
+        // backward one would retire the incumbent LIVE twin and then stamp the slot back to the
+        // dead view's generation.
+        //
+        // m-8: THE FIRST ASSERTION BELOW CANNOT DISTINGUISH THE TWO OUTCOMES and its message
+        // must not claim it does. GetOrCreate(handle) calls entry.backend.reset() before it
+        // stamps, so an ADOPTED backward generation yields a null BackendPtr& just as a refused
+        // one does. What separates refusal from adoption is the SECOND assertion: after an
+        // adoption the live twin at `second` is gone. The first is kept because a non-null there
+        // would mean the table handed back the incumbent's own twin under the dead handle, which
+        // is a third outcome and a worse one.
+        auto& stale = table.GetOrCreate(first);
+        EXPECT_EQ(stale, nullptr)
+            << "SamplerViewCso: a stale handle was answered with the LIVE twin at its slot (this "
+               "assertion cannot tell a refusal from an adoption - the next one does)";
+        EXPECT_NE(table.FindByHandle(second), nullptr)
+            << "SamplerViewCso: the live twin was destroyed by a handle from its slot's past - "
+               "the backward generation was ADOPTED rather than refused";
+
+        table.ReleaseByHandle(second);
+        MG_Pipe::MGPipeSlots().Free(MG_Pipe::MGPipeKind::SamplerViewCso, second);
+    }
+}
+
+// P4a (ID-8): the backend death notice is the REDUNDANT SECOND PATH for every kind the client
+// mints, and it must be IDEMPOTENT - the client's own helper emits the wire delete, raises this
+// notice and frees the slot, in that order, so whichever of the two frees first wins and the
+// other must find nothing and do nothing.
+//
+// Driven through the REAL consumer the backend installed rather than through a recording stub:
+// what is under test is Espryt's OnFrontendStateObjectDestroyed arm, including the SamplerViewCso
+// arm P4a adds, and a stub would prove only that the test can call itself.
+TEST(DirectGLESSlotTable, ADeathNoticeForEveryP4aKindIsIdempotent) {
+    using namespace MobileGL;
+    using namespace MobileGL::MG_Backend::DirectGLES;
+    using namespace MobileGL::MG_State::GLState;
+
+    if (!EsprytSlotTablesEnabled()) {
+        GTEST_SKIP() << "the legacy arm keys twins on the frontend heap address and cannot answer "
+                        "a death notice at all";
+    }
+
+    const MG_State::GLState::StateObjectDeathOps* ops = MG_State::GLState::GetStateObjectDeathOps();
+    ASSERT_NE(ops, nullptr) << "the backend installed no death-notice consumer";
+    ASSERT_NE(ops->OnDestroyed, nullptr);
+
+    // The sampler view first, because it is the arm P4a adds and the only kind whose notice
+    // names a lifetime id belonging to ANOTHER object (the texture the view was minted off).
+    {
+        using SamplerViewImpl::BackendSamplerViewObject;
+        using SamplerViewImpl::g_backendSamplerViews;
+
+        auto owner = MakeShared<TextureObject2D>(0u);
+        const Uint64 lifetimeId = owner->GetLifetimeId();
+        const MG_Pipe::MGPipeHandle view =
+            MG_Pipe::MGPipeSlots().Acquire(MG_Pipe::MGPipeKind::SamplerViewCso, lifetimeId);
+        ASSERT_FALSE(MG_Pipe::MGPipeHandleIsNull(view));
+        g_backendSamplerViews.GetOrCreate(view) = MakeShared<BackendSamplerViewObject>();
+        ASSERT_NE(g_backendSamplerViews.FindByHandle(view), nullptr);
+
+        ops->OnDestroyed(MG_Pipe::MGPipeKind::SamplerViewCso, lifetimeId);
+        EXPECT_EQ(g_backendSamplerViews.FindByHandle(view), nullptr)
+            << "the sampler-view notice left the twin behind, so the slot's next owner would "
+               "inherit a dead texture's resolved view";
+        EXPECT_TRUE(MG_Pipe::MGPipeHandleIsNull(
+            MG_Pipe::MGPipeSlots().FindByLifetimeId(MG_Pipe::MGPipeKind::SamplerViewCso, lifetimeId)))
+            << "the notice did not return the slot";
+
+        // The second path. The client's helper calls Free right after raising the notice, and a
+        // Free on a slot that is no longer live at that generation is a proven no-op
+        // (SlotAllocator.cpp:117-119) - so this is the shape that actually ships, twice over.
+        ops->OnDestroyed(MG_Pipe::MGPipeKind::SamplerViewCso, lifetimeId);
+        MG_Pipe::MGPipeSlots().Free(MG_Pipe::MGPipeKind::SamplerViewCso, view);
+        ops->OnDestroyed(MG_Pipe::MGPipeKind::SamplerViewCso, lifetimeId);
+        EXPECT_EQ(g_backendSamplerViews.FindByHandle(view), nullptr);
+
+        // And the slot really is back: a successor gets it with a moved generation, which is
+        // the property a double free would break by skipping one.
+        auto successor = MakeShared<TextureObject2D>(0u);
+        const MG_Pipe::MGPipeHandle reused = MG_Pipe::MGPipeSlots().Acquire(
+            MG_Pipe::MGPipeKind::SamplerViewCso, successor->GetLifetimeId());
+        EXPECT_EQ(reused.Slot, view.Slot);
+        EXPECT_NE(reused.Gen, view.Gen);
+        MG_Pipe::MGPipeSlots().Free(MG_Pipe::MGPipeKind::SamplerViewCso, reused);
+    }
+
+    // The five kinds that DO have a frontend object: their notice is raised by the object's own
+    // destructor today and by the client's helper after P4a's client packages land, so it is
+    // delivered twice for one death. A second delivery must be a no-op rather than a second
+    // free - which is what would drop a successor's twin under it.
+    struct KindCase {
+        const char* name;
+        MG_Pipe::MGPipeKind kind;
+        Uint64 lifetimeId;
+        // m-9: the handle the object held before it died, so the ABA leg below can prove the
+        // slot came back AT A MOVED GENERATION. ID-8's third case ("a notice for a slot
+        // re-minted at a new generation") was covered for SamplerViewCso only; a double free
+        // skips a generation, and nothing here would have caught that for the other five.
+        MG_Pipe::MGPipeHandle handle;
+    };
+    Vector<KindCase> cases;
+    {
+        auto texture = MakeShared<TextureObject2D>(0u);
+        auto renderbuffer = MakeShared<RenderbufferObject>(0u);
+        auto framebuffer = MakeShared<FramebufferObject>(1u);
+        auto sampler = MakeShared<SamplerObject>(0u);
+        auto program = MakeShared<ProgramObject>(0u);
+
+        TextureImpl::g_backendTextureObjects.GetOrCreate(SharedPtr<ITextureObject>(texture));
+        RenderbufferImpl::g_backendRenderbufferObjects.GetOrCreate(renderbuffer);
+        FramebufferImpl::g_backendFramebufferObjects.GetOrCreate(framebuffer);
+        SamplerImpl::g_backendSamplerObjects.GetOrCreate(sampler);
+        PrgramImpl::g_backendProgramObjects.GetOrCreate(program);
+
+        const auto handleFor = [](MG_Pipe::MGPipeKind kind, Uint64 lifetimeId) {
+            return MG_Pipe::MGPipeSlots().FindByLifetimeId(kind, lifetimeId);
+        };
+        cases.push_back({"Texture", MG_Pipe::MGPipeKind::Texture, texture->GetLifetimeId(),
+                         handleFor(MG_Pipe::MGPipeKind::Texture, texture->GetLifetimeId())});
+        cases.push_back({"Renderbuffer", MG_Pipe::MGPipeKind::Renderbuffer, renderbuffer->GetLifetimeId(),
+                         handleFor(MG_Pipe::MGPipeKind::Renderbuffer, renderbuffer->GetLifetimeId())});
+        cases.push_back({"Framebuffer", MG_Pipe::MGPipeKind::Framebuffer, framebuffer->GetLifetimeId(),
+                         handleFor(MG_Pipe::MGPipeKind::Framebuffer, framebuffer->GetLifetimeId())});
+        cases.push_back({"SamplerCso", MG_Pipe::MGPipeKind::SamplerCso, sampler->GetLifetimeId(),
+                         handleFor(MG_Pipe::MGPipeKind::SamplerCso, sampler->GetLifetimeId())});
+        cases.push_back({"ShaderCso", MG_Pipe::MGPipeKind::ShaderCso, program->GetLifetimeId(),
+                         handleFor(MG_Pipe::MGPipeKind::ShaderCso, program->GetLifetimeId())});
+
+        for (const auto& one : cases) {
+            EXPECT_FALSE(MG_Pipe::MGPipeHandleIsNull(
+                MG_Pipe::MGPipeSlots().FindByLifetimeId(one.kind, one.lifetimeId)))
+                << one.name << ": nothing was twinned, so this walk proves nothing";
+        }
+        // The real destructors run here and raise the first notice.
+    }
+
+    for (const auto& one : cases) {
+        EXPECT_TRUE(MG_Pipe::MGPipeHandleIsNull(
+            MG_Pipe::MGPipeSlots().FindByLifetimeId(one.kind, one.lifetimeId)))
+            << one.name << ": the object's own death did not return its slot";
+        // Second and third deliveries: nothing to resolve, nothing to free, no abort.
+        ops->OnDestroyed(one.kind, one.lifetimeId);
+        ops->OnDestroyed(one.kind, one.lifetimeId);
+        EXPECT_TRUE(MG_Pipe::MGPipeHandleIsNull(
+            MG_Pipe::MGPipeSlots().FindByLifetimeId(one.kind, one.lifetimeId)))
+            << one.name << ": a redundant notice resurrected a mapping";
+
+        // m-9, THE ABA LEG: the slot really came back, and its generation MOVED. Two redundant
+        // notices plus the object's own death are three chances to free one slot twice, and a
+        // double free is invisible in every assertion above - it shows up here, as a successor
+        // handed the same {slot, gen} the dead object held, which is precisely the handle a
+        // surviving memo would still be naming.
+        auto successor = MakeShared<TextureObject2D>(0u);
+        const MG_Pipe::MGPipeHandle reused =
+            MG_Pipe::MGPipeSlots().Acquire(one.kind, successor->GetLifetimeId());
+        ASSERT_FALSE(MG_Pipe::MGPipeHandleIsNull(reused)) << one.name;
+        if (reused.Slot == one.handle.Slot) {
+            EXPECT_NE(reused.Gen, one.handle.Gen)
+                << one.name << ": the slot came back at the SAME generation, so a memo holding "
+                              "the dead object's handle would resolve to its successor's twin";
+        }
+        MG_Pipe::MGPipeSlots().Free(one.kind, reused);
+    }
 }
 
 // The two-holder fix, end to end through the REAL Texture registry and the REAL destructor:
@@ -4372,6 +4775,10 @@ TEST(DirectGLESSlotTable, AGenerationBehindTheLiveTwinIsRefusedRatherThanAdopted
     GTEST_SKIP() << "the {slot, gen} twin table is compiled only under MOBILEGL_PIPE_PUSH";
 }
 
+TEST(DirectGLESSlotTable, ADeathNoticeForEveryP4aKindIsIdempotent) {
+    GTEST_SKIP() << "the {slot, gen} twin table is compiled only under MOBILEGL_PIPE_PUSH";
+}
+
 TEST(DirectGLESBufferDrawProbe, ALiveHostMapKeepsTheHandleArmProbeDirtyBetweenTwoDraws) {
     GTEST_SKIP() << "the handle-keyed resource table is compiled only under MOBILEGL_PIPE_PUSH";
 }