Two robustness gaps from the worker migration, both raised in review:
- The raster worker had no failure recovery: a thrown createImageBitmap/font error or a
dropped message would leave the draw promise pending forever, stalling the serialized draw
chain and hanging prepare/playback. Added worker.onerror and a per-job timeout; both settle
the in-flight draw to a logged miss (texture-worker-error / -timeout) so the pipeline
degrades to last-good per the spec instead of hanging. A single settleRasterization path
clears the timer and resolves.
- prepareSpreadTextureRecordsForFlip() called drawSpread() without awaiting it. That was safe
when drawSpread was synchronous, but now that it is async (worker) the flip could race ahead
of the worker draw and miss the resident texture. prewarmFlipTextures now awaits both spread
draws before the resident-texture lookup.
Suite 168 (added assertions for worker error/timeout recovery and the awaited prewarm).
Normal draw path is behaviorally unchanged from the verified worker commit.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
Georg
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