https://github.com/python/cpython/commit/6081d166f191752c4dd17b5c6037bcf446c8dfb9 commit: 6081d166f191752c4dd17b5c6037bcf446c8dfb9 branch: main author: Timofei <[email protected]> committer: kumaraditya303 <[email protected]> date: 2026-07-12T15:38:32+05:30 summary:
gh-151615: Avoid repeated reschedule in asyncio _accept_connection (#151616) Co-authored-by: Kumar Aditya <[email protected]> files: A Misc/NEWS.d/next/Library/2026-06-18-00-39-58.gh-issue-151615.PBsCE1.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 4fa4dd5a885236..492dfcb19dafe2 100644 --- a/Lib/asyncio/selector_events.py +++ b/Lib/asyncio/selector_events.py @@ -206,6 +206,7 @@ def _accept_connection( protocol_factory, sock, sslcontext, server, backlog, ssl_handshake_timeout, ssl_shutdown_timeout, context) + return else: raise # The event loop will catch, log and ignore it. else: diff --git a/Lib/test/test_asyncio/test_selector_events.py b/Lib/test/test_asyncio/test_selector_events.py index 76ba39019e3663..cf46c13fa5e1f3 100644 --- a/Lib/test/test_asyncio/test_selector_events.py +++ b/Lib/test/test_asyncio/test_selector_events.py @@ -1,6 +1,7 @@ """Tests for selector_events.py""" import collections +import errno import selectors import socket import sys @@ -402,6 +403,24 @@ def mock_sock_accept(): self.loop.run_until_complete(asyncio.sleep(0)) self.assertEqual(sock.accept.call_count, backlog + 1) + def test_accept_connection_reschedules_once_on_resource_error(self): + # When accept() fails with a resource error (EMFILE), _accept_connection + # re-runs the error branch backlog+1 times, logging and rescheduling + # _start_serving once per iteration. With early return after first + # exception we avoid this behaviour + sock = mock.Mock() + sock.accept.side_effect = OSError(errno.EMFILE, 'too many open files') + + self.loop.call_exception_handler = mock.Mock() + self.loop._remove_reader = mock.Mock() + self.loop.call_later = mock.Mock() + + self.loop._accept_connection(mock.Mock(), sock, backlog=100) + + self.assertEqual(sock.accept.call_count, 1) + self.assertEqual(self.loop.call_exception_handler.call_count, 1) + self.assertEqual(self.loop.call_later.call_count, 1) + class SelectorTransportTests(test_utils.TestCase): def setUp(self): diff --git a/Misc/NEWS.d/next/Library/2026-06-18-00-39-58.gh-issue-151615.PBsCE1.rst b/Misc/NEWS.d/next/Library/2026-06-18-00-39-58.gh-issue-151615.PBsCE1.rst new file mode 100644 index 00000000000000..1d08dbacef1f79 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2026-06-18-00-39-58.gh-issue-151615.PBsCE1.rst @@ -0,0 +1,2 @@ +Fix :mod:`asyncio` servers repeatedly logging and rescheduling on a single +event loop iteration when ``accept()`` fails with a resource errors. _______________________________________________ Python-checkins mailing list -- [email protected] To unsubscribe send an email to [email protected] https://mail.python.org/mailman3//lists/python-checkins.python.org Member address: [email protected]
