The Android retrace matrix gains a third lane, spawn-acceptance, beside
monolith-control and inproc-acceptance. Until now nothing in CI had ever
started a second MobileGL process on a device at all.
The apk.yml retrace job already carried a `transport` matrix dimension and
already branched on it, so the lane itself is three edits: a row in
github_transport_matrix, an elif in the retrace step, and a summary to render.
What needed thought was the gate.
THE SPAWN LANE IS APK-ONLY, and that is a statement about where evidence is
missing rather than about what spawn can do. Linux already has
test.yml's `retrace-split`, which is {backend, case, transport} over inproc AND
spawn with the two negative controls that make it mean anything. A spawn row in
the Linux transport matrix would pay for a second full sweep proving nothing -
and test.yml's `retrace` job stages no server image, so the lane would not
merely be redundant, it would be red. self_test_transport_matrices now asserts
the absence in both directions, because an accidental removal of the `if apk`
has to be caught in the self-test rather than in CI.
--require-spawn REQUIRES TWO SENTENCES, and the second is the one that matters.
ConfigLoader's marker proves the VALUE RESOLVED - it exists only in the Spawn
arm, which exists only under MOBILEGL_BUILD_DISAGGREGATED - but that is a
statement about a parser. `spawn ARMED - the server role runs in pid N` is
written only after the launch, the connect and the handshake have all
succeeded, and the pid in it is the SERVER's. It is the only line in the log a
same-process run cannot produce.
Both halves red once, measured:
* a monolith run demanded to prove spawn: REFUSED, transport_resolution_marker
false, server_pid null - while the retrace itself scored ssim=1.000000,
which is exactly the trap. OpenRA matches its golden under monolith too, so
the picture has never been the evidence.
* the same run's real spawn log with the one ARMED line deleted: REFUSED,
transport_resolution_marker TRUE and server_pid null. That is the
"resolved the transport and then never left the process" case, isolated.
THE PROOF USES `any` WHERE THE inproc GATE USES `all`, and the difference is
load-bearing rather than a relaxation. Under spawn two processes append to one
MOBILEGL_LOG_FILE_PATH, and the launcher deliberately scrubs every
MOBILEGL_IPC_* from the child's environment (anti-recursion catch (b)) - so the
server's own `Config: IPC` line reads strict=0 role-split-state=0 BY
CONSTRUCTION. Demanding every line match would red every spawn run for the one
thing the design requires.
--use-pbuffer is not optional on this lane: until P12 a spawned server cannot be
handed a window, because an ANativeWindow* is a pointer into the CLIENT's
process (Rule H). MOBILEGL_IPC_SERVER_PATH is deliberately NOT passed -
nativeLibraryDir carries an install-time hash that nothing off the device can
spell, and the Activity resolves it.
The local runner now passes the same knobs and the same --require-* flag CI
does, so "it works locally" can no longer mean "it ran monolith locally". That
change immediately caught its own omission: the first local run with the gate
armed failed on client_ipc_line_present=false because the runner had been
sending MOBILEGL_TRANSPORT alone.
Verified on device 2f7cbe2e: OpenRA.DirectGLES spawn, ssim=1.000000,
mismatchPixels=0, "real spawn transport, server role in pid 9885, and zero
Fatal records confirmed".
It was one case on one backend under one transport: OpenRA, DirectGLES,
inproc. It is now every CI case, both backends, inproc AND spawn - 154 CI
entries, 156 local ctest entries - because every defect the spawn work turned
up was a question about the SERVER's process and not about any one trace or
either backend.
THE DirectVulkan ARM. tools/trace_replay/CMakeLists.txt carried "a
DirectVulkan arm would be measuring a server nobody has written yet". True
when P5 wrote it; false since P5f/P7 landed Magma's server consumers and its
run-ahead readiness gate. Leaving it would have shipped a split shape whose
second backend nothing ever ran - the same class of hole as a lane that runs
monolith under a name that says split. Magma now brings up a server process
of its own and OpenRA retraces across it at ssim=1.000000, which is only
possible because this branch also taught the child to load its config: before
that, a DirectVulkan session brought up a DirectGLES server and the two
halves disagreed about which backend the capability mask describes.
`split` BECOMES AN OPT-OUT. It began as an opt-in naming one case, because
one case was the work. Marking 39 cases `"split": true` would carry no
information and would reinstate the hole the key was written to close, only
mirrored: a case added later would get the monolith arms and be silently
absent from the split ones, and absent is the one state nothing reds on. A CI
case is now in the subset unless it says `"split": false`, which is a
reviewable claim that a trace cannot cross a role boundary.
THE CI MATRIX GAINS A THIRD DIMENSION. The job took {backend, case} and
hard-coded MOBILEGL_TRANSPORT=inproc in its own run block, so `spawn` had no
way into CI at all; the .SPAWN ctest entries existed only for a local build.
It is {backend, case, transport} now, the backends are the case's own
ci_backends rather than a hard-coded DirectGLES, and the artifact names carry
the transport or the two arms of one {backend, case} would overwrite each
other's uploads.
inproc STAYS AS THE CONTROL. Same library, same codec, same applier, same
picture; the only difference is which process the server role runs in.
Running only spawn would leave "did the transport break it?" and "did the
phase break it?" answerable only together - which is the question every
failure in this phase has turned on, including the SIGSEGV that D1 explained.
BOTH NEGATIVE CONTROLS FOLLOW THE ARM. retrace_pull_library_control.sh and
retrace_drop_draw_control.sh each exported MOBILEGL_TRANSPORT=inproc
themselves, so on a spawn job they would have gone on proving something about
the other arm while spawn ran unguarded. They read SPLIT_TRANSPORT now, and
default to inproc so a caller that sets nothing behaves exactly as before.
scripts/ci/control_smoke_test.sh: 22 passed, 0 failed against the stubbed
ctest, including the two modes that matter most - a red whose SSIM never fell
and a knob that armed and dropped nothing.
The spawn arm needs a second binary and the inproc arm needs none, so the job
places libMobileGLServer.so only on the spawn arm and a missing one is a
named failure there rather than a LaunchServer refusal 78 jobs deep.
Measured locally as this lands: 39 of the 78 SPAWN entries complete, all
green. The rest are still running.
- A retrace that exports MOBILEGL_PIPE_VERIFY=1 at a library configured without
-DMOBILEGL_PIPE_VERIFY=ON is a no-op: the frames still match their goldens and the
case reports green having compared nothing. run_trace_case.cmake now demands the
evidence whenever the variable is set to anything but 0/false - mobilegl.log must
exist, must carry "MGPipe: verify armed", and must carry neither
Fatal{PipeVerifyDiffer nor Fatal{UnmigratedPipeInput. With the variable unset the
script is byte-for-byte the old one.
- The Fatal scan is not redundant with the replay's exit status:
MOBILEGL_PIPE_VERIFY_FATAL=0 is the supported triage configuration, and there a
divergence is logged and counted rather than aborted, so the run would finish 0
with its own report sitting unread in the log.
- LABELS retrace on both registrations: the lane was selectable only by regex, so
`ctest -L retrace --no-tests=error` - the spelling that reds a lane which
registered nothing - could not be written at all.
- "verify": true on eight cases (the five 180s cases plus minecraft-1.21.4-in-world,
minecraft-1.21.4-fabric-sodium-in-world and improved-transparency-minecraft-26.3),
and --format github-verify-matrix over that subset: 16 entries, against the full
lane's 77. The verify build compares at every verb boundary and again at every
accessor read, which the design budgets at 5-10x, so the per-push job runs the
subset and the full sweep is a phase-exit / workflow_dispatch run.
- The flag is validated in the manifest loader, not at the matrix, so a non-boolean
or a verify case excluded from CI is a loud error in every consumer instead of a
subset that is quietly one case short.
swung0x48