diff --git a/Doc/library/asyncio-task.rst b/Doc/library/asyncio-task.rst index 24bd36e6431b4f..2aab62c64d2920 100644 --- a/Doc/library/asyncio-task.rst +++ b/Doc/library/asyncio-task.rst @@ -334,6 +334,13 @@ and reliable way to wait for all tasks in the group to finish. Create a task in this task group. The signature matches that of :func:`asyncio.create_task`. + If the task group is inactive (e.g. not yet entered, + already finished, or in the process of shutting down), + we will close the given ``coro``. + + .. versionchanged:: 3.13 + + Close the given coroutine if the task group is not active. Example:: diff --git a/Doc/whatsnew/3.13.rst b/Doc/whatsnew/3.13.rst index 96c8aee5da075a..137dbe6ff1dbed 100644 --- a/Doc/whatsnew/3.13.rst +++ b/Doc/whatsnew/3.13.rst @@ -185,6 +185,12 @@ Other Language Changes (Contributed by Sebastian Pipping in :gh:`115623`.) +* When :func:`asyncio.TaskGroup.create_task` is called on an inactive + :class:`asyncio.TaskGroup`, the given coroutine will be closed (which + prevents a :exc:`RuntimeWarning` about the given coroutine being + never awaited). + + (Contributed by Arthur Tacca and Jason Zhang in :gh:`115957`.) New Modules =========== diff --git a/Lib/asyncio/taskgroups.py b/Lib/asyncio/taskgroups.py index f322b1f6653f6a..57f01230159319 100644 --- a/Lib/asyncio/taskgroups.py +++ b/Lib/asyncio/taskgroups.py @@ -154,10 +154,13 @@ def create_task(self, coro, *, name=None, context=None): Similar to `asyncio.create_task`. """ if not self._entered: + coro.close() raise RuntimeError(f"TaskGroup {self!r} has not been entered") if self._exiting and not self._tasks: + coro.close() raise RuntimeError(f"TaskGroup {self!r} is finished") if self._aborting: + coro.close() raise RuntimeError(f"TaskGroup {self!r} is shutting down") if context is None: task = self._loop.create_task(coro, name=name) diff --git a/Lib/test/test_asyncio/test_taskgroups.py b/Lib/test/test_asyncio/test_taskgroups.py index 7a18362b54e469..1ec8116953f811 100644 --- a/Lib/test/test_asyncio/test_taskgroups.py +++ b/Lib/test/test_asyncio/test_taskgroups.py @@ -7,6 +7,7 @@ import contextlib from asyncio import taskgroups import unittest +import warnings from test.test_asyncio.utils import await_without_task @@ -738,10 +739,7 @@ async def coro2(g): await asyncio.sleep(1) except asyncio.CancelledError: with self.assertRaises(RuntimeError): - g.create_task(c1 := coro1()) - # We still have to await c1 to avoid a warning - with self.assertRaises(ZeroDivisionError): - await c1 + g.create_task(coro1()) with self.assertRaises(ExceptionGroup) as cm: async with taskgroups.TaskGroup() as g: @@ -797,22 +795,25 @@ async def test_taskgroup_double_enter(self): pass async def test_taskgroup_finished(self): - tg = taskgroups.TaskGroup() - async with tg: - pass - coro = asyncio.sleep(0) - with self.assertRaisesRegex(RuntimeError, "is finished"): - tg.create_task(coro) - # We still have to await coro to avoid a warning - await coro + async def create_task_after_tg_finish(): + tg = taskgroups.TaskGroup() + async with tg: + pass + coro = asyncio.sleep(0) + with self.assertRaisesRegex(RuntimeError, "is finished"): + tg.create_task(coro) + + # Make sure the coroutine was closed when submitted to the inactive tg + # (if not closed, a RuntimeWarning should have been raised) + with warnings.catch_warnings(record=True) as w: + await create_task_after_tg_finish() + self.assertEqual(len(w), 0) async def test_taskgroup_not_entered(self): tg = taskgroups.TaskGroup() coro = asyncio.sleep(0) with self.assertRaisesRegex(RuntimeError, "has not been entered"): tg.create_task(coro) - # We still have to await coro to avoid a warning - await coro async def test_taskgroup_without_parent_task(self): tg = taskgroups.TaskGroup() @@ -821,8 +822,16 @@ async def test_taskgroup_without_parent_task(self): coro = asyncio.sleep(0) with self.assertRaisesRegex(RuntimeError, "has not been entered"): tg.create_task(coro) - # We still have to await coro to avoid a warning - await coro + + def test_coro_closed_when_tg_closed(self): + async def run_coro_after_tg_closes(): + async with taskgroups.TaskGroup() as tg: + pass + coro = asyncio.sleep(0) + with self.assertRaisesRegex(RuntimeError, "is finished"): + tg.create_task(coro) + loop = asyncio.get_event_loop() + loop.run_until_complete(run_coro_after_tg_closes()) if __name__ == "__main__": diff --git a/Misc/NEWS.d/next/Library/2024-03-02-11-31-49.gh-issue-115957.C-3Z_U.rst b/Misc/NEWS.d/next/Library/2024-03-02-11-31-49.gh-issue-115957.C-3Z_U.rst new file mode 100644 index 00000000000000..72988cc63b03cf --- /dev/null +++ b/Misc/NEWS.d/next/Library/2024-03-02-11-31-49.gh-issue-115957.C-3Z_U.rst @@ -0,0 +1 @@ +When ``asyncio.TaskGroup.create_task`` is called on an inactive ``asyncio.TaskGroup``, the given coroutine will be closed (which prevents a ``RuntimeWarning``).