The GL root cause was fixed in fcade06 (the gpu_us query-ring stale
errors). This closes the remaining design debt: a genuinely-failed
UploadMeshData was dropped permanently.
Exact mechanism (traced this session): UploadMeshData's catch returns
null, the staged item is already consumed, and _renderData stays empty -
but the prepared data lingers in _cpuMeshCache, so the #128 EnsureLoaded
re-arm hits PrepareMeshDataAsync's CPU-cache short-circuit
(ObjectMeshManager.cs:448-453) which returns the cached data WITHOUT
re-staging it for upload. The mesh stays invisible until CPU-cache
eviction - session-sticky under low cache pressure (the in-tower
scenario).
Fix: the per-frame Tick drain (WbMeshAdapter) now re-stages a failed
upload for the NEXT frame via ObjectMeshManager.UploadOrRequeue, bounded
by MaxUploadRetries (3). The attempt counter lives on the ObjectMeshData
object so it resets to 0 naturally on re-prepare. Re-stages are
collected and re-enqueued AFTER the drain loop, never inside it, so a
deterministic failure cannot spin the queue within a single frame; past
the cap it gives up with a loud [up-retry] ... giving up line - a
genuine GL defect now surfaces instead of the old silent permanent drop
or an unbounded retry storm. Retail loads content synchronously and has
no such failure mode; this converges the async pipeline toward that
guarantee.
The uncaught GenerateMipmaps path (open-question c) is INTENTIONALLY
left to surface errors - a blanket catch there would mask future real
defects (no-workarounds rule), and its trigger (fcade06) is retired.
No visual gate (robustness). Build green; App.Tests 264 + WbMeshAdapter
tests green. No GL-context test seam exists for the upload path, so the
bounded retry is verified by construction + the regression suite.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
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