diff --git a/Lib/asyncio/base_events.py b/Lib/asyncio/base_events.py index 000647f57dd9e3..5dbe4b28d236d3 100644 --- a/Lib/asyncio/base_events.py +++ b/Lib/asyncio/base_events.py @@ -17,7 +17,6 @@ import collections.abc import concurrent.futures import errno -import functools import heapq import itertools import os @@ -1140,11 +1139,18 @@ async def create_connection( except OSError: continue else: # using happy eyeballs - sock, _, _ = await staggered.staggered_race( - (functools.partial(self._connect_sock, - exceptions, addrinfo, laddr_infos) - for addrinfo in infos), - happy_eyeballs_delay, loop=self) + sock = (await staggered.staggered_race( + ( + # can't use functools.partial as it keeps a reference + # to exceptions + lambda addrinfo=addrinfo: self._connect_sock( + exceptions, addrinfo, laddr_infos + ) + for addrinfo in infos + ), + happy_eyeballs_delay, + loop=self, + ))[0] # can't use sock, _, _ as it keeks a reference to exceptions if sock is None: exceptions = [exc for sub in exceptions for exc in sub] diff --git a/Lib/asyncio/staggered.py b/Lib/asyncio/staggered.py index c3a7441a7b091d..326c6f708944af 100644 --- a/Lib/asyncio/staggered.py +++ b/Lib/asyncio/staggered.py @@ -133,6 +133,7 @@ async def run_one_coro(previous_failed) -> None: raise d.exception() return winner_result, winner_index, exceptions finally: + del exceptions # Make sure no tasks are left running if we leave this function for t in running_tasks: t.cancel() diff --git a/Lib/test/test_asyncio/test_streams.py b/Lib/test/test_asyncio/test_streams.py index d32b7ff251885d..0688299447d064 100644 --- a/Lib/test/test_asyncio/test_streams.py +++ b/Lib/test/test_asyncio/test_streams.py @@ -1200,6 +1200,24 @@ async def handle_echo(reader, writer): messages = self._basetest_unhandled_exceptions(handle_echo) self.assertEqual(messages, []) + def test_open_connection_happy_eyeball_refcycles(self): + port = socket_helper.find_unused_port() + async def main(): + exc = None + try: + await asyncio.open_connection( + host="localhost", + port=port, + happy_eyeballs_delay=0.25, + ) + except* OSError as excs: + # can't use assertRaises because that clears frames + exc = excs.exceptions[0] + self.assertIsNotNone(exc) + self.assertListEqual(gc.get_referrers(exc), []) + + asyncio.run(main()) + if __name__ == '__main__': unittest.main() diff --git a/Misc/NEWS.d/next/Library/2024-10-01-17-12-20.gh-issue-124858.Zy0tvT.rst b/Misc/NEWS.d/next/Library/2024-10-01-17-12-20.gh-issue-124858.Zy0tvT.rst new file mode 100644 index 00000000000000..c05d24a7c5aacb --- /dev/null +++ b/Misc/NEWS.d/next/Library/2024-10-01-17-12-20.gh-issue-124858.Zy0tvT.rst @@ -0,0 +1 @@ +Fix reference cycles left in tracebacks in :func:`asyncio.open_connection` when used with ``happy_eyeballs_delay``