https://github.com/python/cpython/commit/ce0ae1d784871085059a415aa589d9bd16ea8301
commit: ce0ae1d784871085059a415aa589d9bd16ea8301
branch: main
author: Jason Zhang <[email protected]>
committer: gvanrossum <[email protected]>
date: 2024-03-06T12:20:26-08:00
summary:
gh-115957: Close coroutine if TaskGroup.create_task() raises an error (#116009)
files:
A Misc/NEWS.d/next/Library/2024-03-02-11-31-49.gh-issue-115957.C-3Z_U.rst
M Doc/library/asyncio-task.rst
M Doc/whatsnew/3.13.rst
M Lib/asyncio/taskgroups.py
M Lib/test/test_asyncio/test_taskgroups.py
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``).
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