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- ID-133: escalation (iii) in MGPipeBarriered - a draw_vbo with NumDraws > 1 that is NOT
kDrawIsIndirect is barriered. Espryt's indirect multi-draw tiers reach
MultiDrawImpl::RunIndirect, whose apply reads the client's GL_DRAW_INDIRECT_BUFFER binding
(BoundDrawIndirectBufferId, MultiDraw.cpp:87) - GetBufferBindingSlot, retiring in P8 - and
unbarriered that is Fatal{UnmigratedPipeInput, "GetBufferBindingSlot@DrawArrays"} on 18 lane
entries. Backtrace of the aborting thread, verbatim frames: CountBarrierPull <-
MultiDrawImpl::RunIndirect <- MultiDrawImpl::DrawElementsBatch <- ServerVerbSink::OnDrawVbo
<- PipeWireDecoder::DecodeAndApply <- PipeApplier::ApplyOne.
- TWO PREMISE CORRECTIONS, both measured, both in the report and in the contract. (a) There is
no indirect multi-draw OP: all twenty draw entry points collapse onto draw_vbo, and the tier
is resolved on the server per batch (ResolveTierForBatch), so the escalation cannot be keyed
on the tier and its cost is NOT confined to the opt-in tier lanes - a plain glMultiDraw* now
waits on the auto -> ext default too. NumDraws > 1 is the narrowest wire fact that contains
the reaching set; kDrawIsIndirect is excluded so Sodium's indirect draw, which resolves by
handle and pulls nothing, keeps running ahead. (b) The read is a SAVE/RESTORE of a GL binding
name around the tier's own scratch buffer, not a data dependency - so it can be retired
outright by giving BoundDrawIndirectBufferId the handle arm its neighbour
ResolveBoundIndexBuffer already has, and this escalation withdrawn. That is three lines in
MultiDraw.cpp, which ID-113 gives to mv, so it is reported rather than edited here.
- The client's half is verb-keyed because the fill decision is asked before the record exists:
{MultiDrawArrays, MultiDrawElements, MultiDrawElementsBaseVertex} is exactly the set whose
record can carry NumDraws > 1 without kDrawIsIndirect. The inclusion goes that way round on
purpose - a record the server calls barriered whose fields the client did not fill would be
an ADMITTED pull of a stale value, which is worse than the abort.
- ID-134: the two ClientVertexArrayScenario entries get the label integration-clientarrays-split
and an expected-red CI step that asserts the MARKER, shaped like gl's Magma lane. ID-131 heeded
by COUNTING, not by assuming: -L integration-split 181 -> 179, -L integration-gpu 1359 -> 1357,
the new label selects exactly 2. The step branches on whether run-ahead is actually ARMED,
because kMGPipeP5eRunAheadReady is a BUILD constant: on a head where it is false the refusal is
unreachable and the entries are legitimately green, so an unconditional demand for red would
fail for the one reason that is not a defect. The client says which world it is in in its own
log line; delete the green branch when the flip lands for good.
- CONTRACT-P5E §3.5 amended to the code: "outside a barriered fill" rested on the caller's claim
about the FUTURE, and a guard whose exemption cannot be false on the class it exists for is not
a guard - it never fired on any of the 70 red entries. The landed rule is "not while the applier
is inside, barriered fill or not", with the fill sites taking §2.5's forced wait first, twice
per filling verb because the block is written either side of the emitters.
- AND §3.2 IS MARKED UNLANDED, which nobody had noticed: "the server's stamp is server-private
… never into the shared block" describes storage the applier owns, and
MGPipeServerStampVerbBoundary still writes m_filled / m_currentVerb / m_serverStampedVerb into
gPipeInputs itself. That gap is what made the race possible. Splitting the stamp is the P11
item - but per-role stamps WITHOUT versioning the BARRIER_PULLED values would be worse than
today, because it turns a loud Fatal into a silent stale read.
- §2.1 carries escalation (iii) as a row, per its own rule that a new escalation is a ruling and
a row in the contract rather than a condition at a call site.
- Gate on the flipped head: unit 2256/2256, isplit 179/179 HARD GREEN, gens rc=0, doc citations
rc=0 (the three remaining are CONTRACT-P5.md's and pre-date this branch).