https://github.com/python/cpython/commit/830e10651b1f45cd0af36ff611397b9f531... commit: 830e10651b1f45cd0af36ff611397b9f53171220 branch: main author: jb2170 <email@jb2170.com> committer: kumaraditya303 <kumaraditya@python.org> date: 2025-01-03T10:32:36Z summary: gh-127529: Correct asyncio's `accept_connection` behaviour for handling `ConnectionAbortedError` (#127532) Co-authored-by: Kumar Aditya <kumaraditya@python.org> files: A Misc/NEWS.d/next/Library/2024-12-02-19-13-19.gh-issue-127529.Pj1Xtf.rst M Lib/asyncio/selector_events.py M Lib/test/test_asyncio/test_selector_events.py diff --git a/Lib/asyncio/selector_events.py b/Lib/asyncio/selector_events.py index f1ab9b12d69a5d..50992a607b3a1c 100644 --- a/Lib/asyncio/selector_events.py +++ b/Lib/asyncio/selector_events.py @@ -180,9 +180,13 @@ def _accept_connection( logger.debug("%r got a new connection from %r: %r", server, addr, conn) conn.setblocking(False) - except (BlockingIOError, InterruptedError, ConnectionAbortedError): - # Early exit because the socket accept buffer is empty. - return None + except ConnectionAbortedError: + # Discard connections that were aborted before accept(). + continue + except (BlockingIOError, InterruptedError): + # Early exit because of a signal or + # the socket accept buffer is empty. + return except OSError as exc: # There's nowhere to send the error, so just log it. if exc.errno in (errno.EMFILE, errno.ENFILE, diff --git a/Lib/test/test_asyncio/test_selector_events.py b/Lib/test/test_asyncio/test_selector_events.py index f984dc96415ba3..c9217d04bcd322 100644 --- a/Lib/test/test_asyncio/test_selector_events.py +++ b/Lib/test/test_asyncio/test_selector_events.py @@ -364,6 +364,31 @@ def test_accept_connection_multiple(self): self.loop.run_until_complete(asyncio.sleep(0)) self.assertEqual(sock.accept.call_count, backlog) + def test_accept_connection_skip_connectionabortederror(self): + sock = mock.Mock() + + def mock_sock_accept(): + # mock accept(2) returning -ECONNABORTED every-other + # time that it's called. This applies most to OpenBSD + # whose sockets generate this errno more reproducibly than + # Linux and other OS. + if sock.accept.call_count % 2 == 0: + raise ConnectionAbortedError + return (mock.Mock(), mock.Mock()) + + sock.accept.side_effect = mock_sock_accept + backlog = 100 + # test that _accept_connection's loop calls sock.accept + # all 100 times, continuing past ConnectionAbortedError + # instead of unnecessarily returning early + mock_obj = mock.patch.object + with mock_obj(self.loop, '_accept_connection2') as accept2_mock: + self.loop._accept_connection( + mock.Mock(), sock, backlog=backlog) + # as in test_accept_connection_multiple avoid task pending + # warnings by using asyncio.sleep(0) + self.loop.run_until_complete(asyncio.sleep(0)) + self.assertEqual(sock.accept.call_count, backlog) class SelectorTransportTests(test_utils.TestCase): diff --git a/Misc/NEWS.d/next/Library/2024-12-02-19-13-19.gh-issue-127529.Pj1Xtf.rst b/Misc/NEWS.d/next/Library/2024-12-02-19-13-19.gh-issue-127529.Pj1Xtf.rst new file mode 100644 index 00000000000000..26f2fd5923ab7b --- /dev/null +++ b/Misc/NEWS.d/next/Library/2024-12-02-19-13-19.gh-issue-127529.Pj1Xtf.rst @@ -0,0 +1,4 @@ +Correct behavior of +:func:`!asyncio.selector_events.BaseSelectorEventLoop._accept_connection` +in handling :exc:`ConnectionAbortedError` in a loop. This improves +performance on OpenBSD.