stream: fix Writable.toWeb() hang on synchronous drain#61197
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stream: fix Writable.toWeb() hang on synchronous drain#61197Han5991 wants to merge 1 commit intonodejs:mainfrom
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A race condition in the Writable.toWeb() adapter caused the stream to hang if the underlying Node.js Writable emitted a 'drain' event synchronously during a write() call. This often happened when highWaterMark was set to 0. By checking writableNeedDrain immediately after a backpressured write, the adapter now correctly detects if the stream has already drained, resolving the backpressure promise instead of waiting indefinitely for an event that has already occurred. Fixes: nodejs#61145
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This PR fixes a race condition in Writable.toWeb() where the resulting WritableStream would hang if the underlying Node.js
Writable emitted the 'drain' event synchronously during a write() call.
This issue typically manifests when highWaterMark is set to 0, or in custom stream implementations that do not defer 'drain'
emissions. In such cases, the 'drain' event could fire before the adapter had a chance to set up the backpressurePromise and the
listener, causing the adapter to wait indefinitely for an event that had already occurred.
The fix involves checking streamWritable.writableNeedDrain immediately after write() returns false. If the stream is already
drained (i.e., writableNeedDrain is false), the backpressure promise is resolved immediately.
Related Issue
Fixes: #61145