Fix AsyncioConnection race conditions causing EBADF errors (#614)#697
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Fix AsyncioConnection race conditions causing EBADF errors (#614)#697dkropachev wants to merge 1 commit intomasterfrom
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Fix race conditions in AsyncioConnection that cause "[Errno 9] Bad file descriptor" errors during node restarts, especially with TLS: 1. close() now waits for _close() to complete when called from outside the event loop thread, eliminating the window where is_closed=True but the socket fd is still open. 2. handle_read() sets last_error on server EOF so factory() detects dead connections instead of returning them to callers. 3. handle_write() treats peer disconnections as clean close instead of defuncting, and both I/O handlers skip defunct() if the connection is already shutting down. Peer-disconnect detection is extracted into _is_peer_disconnect() helper covering platform-specific behaviors: - Windows: ProactorEventLoop raises plain OSError with winerror 10054 (WSAECONNRESET) or 10053 (WSAECONNABORTED) instead of ConnectionResetError. Detection uses ConnectionError base class plus winerror check. - macOS: Raises OSError(57) ENOTCONN when writing to a peer-disconnected socket, which is not a ConnectionError subclass. Detection uses errno-based checks for ENOTCONN, ESHUTDOWN, ECONNRESET, and ECONNABORTED. - Windows _close(): ProactorEventLoop does not support remove_reader/remove_writer (raises NotImplementedError). These calls are wrapped so the socket is always closed regardless, and try/finally ensures connected_event is always set even if cleanup fails.
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Summary
close()to wait for_close()completion from non-event-loop threads, eliminating the window whereis_closed=Truebut the socket fd is still open (root cause of EBADF)last_erroron server EOF inhandle_read()sofactory()detects dead connections instead of returning themis_closed/is_defunctguard inpush()to reject writes on closed connectionsBrokenPipeError/ConnectionResetErrorinhandle_write()as clean peer disconnections instead of defuncting, and skipdefunct()in both I/O handlers if the connection is already shutting downTest plan
tests/unit/io/test_asyncio_race_614.pycover all four race conditions using real socket pairs