Coordinator-directed follow-up. The buffer-and-drain seam diverged from
the original on the exception path: pre-MP1a, CollectEmittersFromScript
enqueued particle-preload meshes DIRECTLY into _stagedMeshData
mid-Prepare, so preloads staged before a later throw in the same
Prepare* call (reachable via PrepareEnvCellMeshData side-staging during
its StaticObjects loop, then PrepareCellStructMeshData throwing on a
malformed-dat texture decode) were already safely enqueued. The drain
version only flushed after a successful return — on throw, entries
stranded on the shared extractor until an unrelated successful call
flushed them, and were silently dropped on dispose.
Fix: MeshExtractor takes an Action<ObjectMeshData>? sideStagedSink
constructor parameter; the two CollectEmittersFromScript sites become
_sideStagedSink?.Invoke(meshData) — the original code shape (immediate
hand-off) at those exact lines. ObjectMeshManager wires the sink to
_stagedMeshData.Enqueue, restoring the original immediate-enqueue
semantics including on mid-Prepare throw. _sideStaged buffer,
DrainSideStaged(), and the ProcessQueueAsync drain loop are deleted.
The MP1b bake tool passes its own collector.
Inventory doc updated: MP1a note now records the sink seam and the
Content-owned upload enums, so its no-behavior-change claim is accurate.
dotnet build green; full test suite 4059 passed / 0 failed / 4 skipped.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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