https://github.com/python/cpython/commit/872e4c74367b415f91cd16a239530095593fba3b commit: 872e4c74367b415f91cd16a239530095593fba3b branch: 3.14 author: Miss Islington (bot) <[email protected]> committer: kumaraditya303 <[email protected]> date: 2026-10-29T18:00:49+05:30 summary:
[3.14] gh-157856: Fix `asyncio.as_completed()` outside a running event loop (GH-157857) (#160231) gh-157856: Fix `asyncio.as_completed()` outside a running event loop (GH-157857) (cherry picked from commit b12fcffdb153d992e665510e23bfaa14519de56c) Co-authored-by: Aslan Osmanov <[email protected]> Co-authored-by: Andrew Svetlov <[email protected]> files: A Misc/NEWS.d/next/Library/2026-09-20-12-00-00.gh-issue-157856.wq4xuF.rst M Lib/asyncio/tasks.py M Lib/test/test_asyncio/test_tasks.py diff --git a/Lib/asyncio/tasks.py b/Lib/asyncio/tasks.py index c5a07d8375100f..9889a990daa155 100644 --- a/Lib/asyncio/tasks.py +++ b/Lib/asyncio/tasks.py @@ -567,7 +567,13 @@ def __init__(self, aws, timeout): self._timeout_handle = None loop = events.get_event_loop() - self._cur_task = current_task() + # The iterator may be created outside of a running event loop and + # then driven with loop.run_until_complete(), in which case there + # is no current task to record as the waiter. + if events._get_running_loop() is loop: + self._cur_task = current_task(loop) + else: + self._cur_task = None todo = {ensure_future(aw, loop=loop) for aw in set(aws)} for f in todo: f.add_done_callback(self._handle_completion) diff --git a/Lib/test/test_asyncio/test_tasks.py b/Lib/test/test_asyncio/test_tasks.py index 6594c0ace89bd5..6c4c6e5086ac05 100644 --- a/Lib/test/test_asyncio/test_tasks.py +++ b/Lib/test/test_asyncio/test_tasks.py @@ -1843,6 +1843,22 @@ async def coro(): futs = asyncio.as_completed([a]) list(futs) + def test_as_completed_outside_running_loop(self): + # gh-157856: as_completed() must not require a running event loop + # when the iterator is created, only when it is driven. + loop = self.new_test_loop() + self.addCleanup(asyncio.set_event_loop, None) + asyncio.set_event_loop(loop) + + async def coro(v): + await asyncio.sleep(0) + return v + + tasks = [loop.create_task(coro(v)) for v in (1, 2)] + futs = asyncio.as_completed(tasks) + results = [loop.run_until_complete(f) for f in futs] + self.assertEqual(sorted(results), [1, 2]) + def test_as_completed_coroutine_use_running_loop(self): loop = self.new_test_loop() diff --git a/Misc/NEWS.d/next/Library/2026-09-20-12-00-00.gh-issue-157856.wq4xuF.rst b/Misc/NEWS.d/next/Library/2026-09-20-12-00-00.gh-issue-157856.wq4xuF.rst new file mode 100644 index 00000000000000..9f221fa657d429 --- /dev/null +++ b/Misc/NEWS.d/next/Library/2026-09-20-12-00-00.gh-issue-157856.wq4xuF.rst @@ -0,0 +1,3 @@ +Fix :func:`asyncio.as_completed` raising :exc:`RuntimeError` ("no running +event loop") when the iterator is created outside of a running event loop and +driven with :meth:`loop.run_until_complete() <asyncio.loop.run_until_complete>`. _______________________________________________ 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]
