fix(asyncio): do not hang when async_playwright() is cancelled while connecting - #3177
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Yury Semikhatsky (yury-s) wants to merge 3 commits into
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fix(asyncio): do not hang when async_playwright() is cancelled while connecting#3177Yury Semikhatsky (yury-s) wants to merge 3 commits into
Yury Semikhatsky (yury-s) wants to merge 3 commits into
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…connecting Cancelling __aenter__ left the driver process and the transport tasks running with no owner. At loop shutdown the init task absorbed its one cancellation inside Channel._abort() waiting for a reply that could never arrive, so asyncio.run() never returned. - stop the connection when __aenter__ is cancelled - allow PipeTransport.request_stop() before the driver has spawned - release pending protocol callbacks when the Connection.run() task is cancelled at loop shutdown - retrieve callback exceptions in Channel._abort() even when its wait is interrupted by another cancellation Fixes: microsoft/playwright#42296
- reuse __aexit__ for teardown when __aenter__ fails or is cancelled, mirroring the sync context manager - move _stopped_future and wait_until_stopped() into the Transport base, deleting both subclass copies - reuse request_stop() when connect() finishes after a stop request - skip sending __abort__ over a closed connection
Yury Semikhatsky (yury-s)
requested review from
Simon Knott (Skn0tt),
Dmitry Gozman (dgozman) and
Pavel Feldman (pavelfeldman)
August 19, 2026 00:38
| await self._transport.run() | ||
| try: | ||
| await self._transport.run() | ||
| except asyncio.CancelledError: |
Contributor
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Why only on CancelledError and not on any error? How is this one special?
| async def _abort( | ||
| self, object: ChannelOwner, callback: ProtocolCallback, reason: str | ||
| ) -> None: | ||
| if not self._closed_error: |
Contributor
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I think we would benefit from another test, where we cancel a task like click(), while at the same time closing the connection. I don't think existing tests cover this change.
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Summary
__aenter__fails or is cancelled, reusing__aexit__like the sync context manager doesPipeTransport.request_stop()before the driver has spawnedConnection.run()task is cancelled at loop shutdown, so their cancellation is not absorbed byChannel._abort()waiting for a reply that can never arriveChannel._abort()even when its wait is interrupted by another cancellationFixes microsoft/playwright#42296