Files
MobileGL/docs
swung0x48 f1b04edfc6 [MG_Backend, MG_IntegrationTest, docs] (P7): the magma vertex-layout refusal splits into one protocol fatal and seven masked attributes
CONTRACT-P7 §3.2's `vertex-layout` and `vertex-format-conversion` rows.
BuildWireVertexInput answered eight different conditions with one `false`, and the single
caller answered that with a P7-marked MagmaWireFatal. So a Magma split session that met a
GL_FIXED array, a dvec on a device with native fp64, or any format without
VK_FORMAT_FEATURE_VERTEX_BUFFER_BIT did not decline the draw: it killed the process. The
monolith arm on the same device has always masked the attribute out and then declined the
draw loudly and once.

The split is by what the reason is ABOUT, not by severity. `buffer-window` is a statement
about the RECORD - an enabled attribute the program reads whose slot lies outside the
window set_vertex_buffers published - so it stays a named Fatal through the hook; it is
what caught the Redmi VAO hash collision fixed in 376c04be. Every other reason is a
statement about what Vulkan can express on this device, and those now set
unsupportedAttribMask and continue, with the monolith arm's own pre-flight in WireDraw.inc
declining the draw when a masked bit is one the program actually reads.

The contract says "the other six"; there are seven. `offset-overflow` post-dates the
audit's count and is an arithmetic guard rather than a shape one. It is masked with the
rest: an attribute whose base offsets cannot be added is one Vulkan cannot fetch, the
monolith arm never computes that sum at all, and masking is strictly safer than a Fatal
for a number no application can reach on purpose.

unsupportedAttribMask now enters the wire layout hash, for the reason the monolith entry's
hash already carries it: two VAOs can otherwise agree on every binding, attribute and
divisor and differ only in which enabled attribute was masked, and a blind hash would hand
one of them the other's pipeline. Omitting it was safe only while the mask was always zero.

vertex-format-conversion becomes a decline for a narrower reason: the converter is only
ever asked for a conversion BuildWireVertexInput already chose, so a refusal means the two
disagree - a defect on this side, not a peer's malformed record.

@P7 census: 15 sites / 4 files -> 13 / 3. Renderer/WireDraw.inc leaves the list entirely.
fatal_census.py unchanged at 79 abort sites / 43 family words / 0 unmarked, as expected:
wave 0 already funnelled these, so retiring a MagmaWireFatal CALL moves no abort count.

New MagmaVertexLayoutScenario, DirectVulkan only (Espryt hands GL_FIXED to a driver that
supports it, so the same name would assert a different fact there). DataType::Fixed32 has
no arm in ToVkVertexFormat at all, which makes it the one unmappable shape reachable on
host lavapipe - §2.5 records that no other P7-marked refusal is. One case has the program
READ the array and asserts the draw declines; the other leaves it enabled but unread and
asserts the draw lands, which is what stops the first being satisfied by "decline every
draw that mentions GL_FIXED". Registered on all three transports and picked up by the
ambient monolith DirectVulkan discovery, so the A/B is direct.

RED-ONCE: `format-map` put back on the protocol verdict reds the three split arms with
`Subprocess aborted` / `Fatal{UnmigratedVerb, "Magma:vertex-layout-buffer-window"}` while
the monolith control stays green - exactly the divergence this closes. Restored: 10/10.

The gating Magma lanes grow with the new entries: split 73 -> 75, spawn 52 -> 54, tcp
54 -> 56. Growth only.

Open for the integrator: the honest family word for buffer-window is ProtocolCorruption,
and MGPipeFatalFamily carries only UnmigratedVerb and RoleViolation. Adding a third costs
a row there plus an adapter arm, and §3.3 keeps the three Magma funnels on UnmigratedVerb
deliberately so the refusal census stays comparable to P5b. Flagged, not decided.
2026-09-22 16:07:59 -04:00
..