stream: fix pipeTo assert when writer is released during microtask - #63733
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stream: fix pipeTo assert when writer is released during microtask#63733colinaaa wants to merge 2 commits into
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pipeTo defers each slow-path write to a microtask so it does not run synchronously during enqueue(). A race allows the pipe to shut down and release its writer after the write is scheduled but before it runs. The deferred write then hits an ERR_INTERNAL_ASSERTION because writer[[stream]] is undefined. Skip the deferred write when shutdown has already started. Fixes: nodejs#63732 Signed-off-by: Qingyu Wang <[email protected]> Assisted-by: Codex
The shuttingDown guard added by the previous commit is too broad: it also skips an already-read chunk while the destination is still writable. The WHATWG Streams spec requires pipeTo to write such chunks during shutdown. Check writer[kState].stream instead. It becomes undefined only after finalize() releases the writer, which is precisely the assertion case. Add a regression test that aborts after enqueue() and verifies that the already-read chunk is written. Signed-off-by: Qingyu Wang <[email protected]> Assisted-by: Codex
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Summary
The deferred write introduced by #61800 wraps the write operation in
queueMicrotask(). A race condition exists where the pipe can shutdown and release the writer between when[kChunk]schedules the microtask and when it executes, causing anERR_INTERNAL_ASSERTIONbecausewriter[[stream]]is undefined.Fix by checking
writer[kState].stream === undefinedin the deferred microtask before attempting the write. This condition is only true afterfinalize()has released the writer, precisely targeting the crash without interfering with the spec requirement that already-read chunks are written to a still-writable destination during shutdown.Fixes: #63732