fix(tsfn): prevent undefined behavior from user callback exceptions#6
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fix(tsfn): prevent undefined behavior from user callback exceptions#6
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- Wrap all TSFN callback invocations in try-catch blocks - Prevents user exceptions from propagating to N-API layer - Fixes VideoDecoder::Flush promise handling race condition - Store deferred promise before enqueue to prevent use-after-move - Add test for flush promise rejection scenario
- Add try/catch blocks around all TSFN callbacks to prevent undefined behavior - Fix flush promise handling to return same promise instance on early rejection - Increase cleanup timeout from 100ms to 10s with warning on timeout - Add comprehensive comments explaining N-API requirements and limitations - Update test to verify flush() rejects on unconfigured encoder
Implements P0-5 from node-api audit plan to prevent use-after-free during
environment teardown (process.exit, worker termination).
Changes:
- Add src/codec_registry.{h,cc} with immortal globals pattern
- Register/unregister all codecs (Video/Audio Encoder/Decoder)
- Add napi_add_env_cleanup_hook to clear registries before teardown
- Document N-API limitation: cleanup hooks cannot reject promises
N-API Limitation:
napi_add_env_cleanup_hook does NOT provide napi_env parameter, making
promise rejection impossible during abnormal shutdown. This is acceptable
per W3C spec - normal shutdown via close() + await flush() works correctly.
Fixes: P0-2, P0-5 from docs/plans/2025-01-04-node-api-audit.md
Tests: 941/946 passing (no new regressions)
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Closing PR as requested |
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Summary
Fixes critical undefined behavior when user-provided callbacks throw exceptions in ThreadSafeFunction contexts.
Changes
TSFN Exception Handling: Wrap all callback invocations in try-catch blocks to prevent exceptions from propagating to the N-API layer
AsyncDecodeWorker::ProcessPacket()- error callbackAsyncEncodeWorker::EmitChunk()- output callbackVideoEncoder::OnOutputTSFN()- output callbackVideoDecoder::Flush Promise Fix: Resolve race condition where promise was moved before enqueue failure could be detected
Why This Matters
Per N-API docs, exceptions thrown in TSFN callbacks cause undefined behavior. This was a critical bug that could crash the Node.js process.
Test Plan