[issue43991] asyncio lock does not get released after task is canceled
Alexander Niederbühl
report at bugs.python.org
Fri Apr 30 14:49:44 EDT 2021
New submission from Alexander Niederbühl <a.niederbuehl at gmail.com>:
If a task gets canceled while holding a lock, the lock is not automatically released. Is that expected, it seems like it could cause a deadlock?
Failing test adapted from Lib/test/test_asyncio/test_locks.py (commit 6bd9288b80):
def test_acquire_cancel(self):
lock = asyncio.Lock()
self.assertTrue(self.loop.run_until_complete(lock.acquire()))
task = self.loop.create_task(lock.acquire())
self.loop.call_soon(task.cancel)
self.assertRaises(
asyncio.CancelledError,
self.loop.run_until_complete, task)
self.assertFalse(lock._waiters)
# Should the lock get released after cancellation?
self.assertFalse(lock.locked())
I stumbled upon this while playing around with TLA+.
----------
components: asyncio
messages: 392499
nosy: a.niederbuehl, asvetlov, yselivanov
priority: normal
severity: normal
status: open
title: asyncio lock does not get released after task is canceled
type: behavior
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Python tracker <report at bugs.python.org>
<https://bugs.python.org/issue43991>
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