diff options
| -rw-r--r-- | Lib/asyncio/locks.py | 17 | ||||
| -rw-r--r-- | Lib/test/test_asyncio/test_locks.py | 22 | ||||
| -rw-r--r-- | Misc/NEWS | 3 |
3 files changed, 37 insertions, 5 deletions
diff --git a/Lib/asyncio/locks.py b/Lib/asyncio/locks.py index deefc93..9266183 100644 --- a/Lib/asyncio/locks.py +++ b/Lib/asyncio/locks.py @@ -176,6 +176,10 @@ class Lock(_ContextManagerMixin): yield from fut self._locked = True return True + except futures.CancelledError: + if not self._locked: + self._wake_up_first() + raise finally: self._waiters.remove(fut) @@ -192,14 +196,17 @@ class Lock(_ContextManagerMixin): """ if self._locked: self._locked = False - # Wake up the first waiter who isn't cancelled. - for fut in self._waiters: - if not fut.done(): - fut.set_result(True) - break + self._wake_up_first() else: raise RuntimeError('Lock is not acquired.') + def _wake_up_first(self): + """Wake up the first waiter who isn't cancelled.""" + for fut in self._waiters: + if not fut.done(): + fut.set_result(True) + break + class Event: """Asynchronous equivalent to threading.Event. diff --git a/Lib/test/test_asyncio/test_locks.py b/Lib/test/test_asyncio/test_locks.py index 152948c..c85e8b1 100644 --- a/Lib/test/test_asyncio/test_locks.py +++ b/Lib/test/test_asyncio/test_locks.py @@ -176,6 +176,28 @@ class LockTests(test_utils.TestCase): self.assertTrue(tb.cancelled()) self.assertTrue(tc.done()) + def test_finished_waiter_cancelled(self): + lock = asyncio.Lock(loop=self.loop) + + ta = asyncio.Task(lock.acquire(), loop=self.loop) + test_utils.run_briefly(self.loop) + self.assertTrue(lock.locked()) + + tb = asyncio.Task(lock.acquire(), loop=self.loop) + test_utils.run_briefly(self.loop) + self.assertEqual(len(lock._waiters), 1) + + # Create a second waiter, wake up the first, and cancel it. + # Without the fix, the second was not woken up. + tc = asyncio.Task(lock.acquire(), loop=self.loop) + lock.release() + tb.cancel() + test_utils.run_briefly(self.loop) + + self.assertTrue(lock.locked()) + self.assertTrue(ta.done()) + self.assertTrue(tb.cancelled()) + def test_release_not_acquired(self): lock = asyncio.Lock(loop=self.loop) @@ -49,6 +49,9 @@ Core and Builtins Library ------- +- bpo-27585: Fix waiter cancellation in asyncio.Lock. + Patch by Mathieu Sornay. + - bpo-30418: On Windows, subprocess.Popen.communicate() now also ignore EINVAL on stdin.write() if the child process is still running but closed the pipe. |