Issue #22970: asyncio: Fix inconsistency cancelling Condition.wait.
Patch by David Coles.
diff --git a/Lib/asyncio/locks.py b/Lib/asyncio/locks.py
index 842d621..741aaf2 100644
--- a/Lib/asyncio/locks.py
+++ b/Lib/asyncio/locks.py
@@ -329,7 +329,13 @@
self._waiters.remove(fut)
finally:
- yield from self.acquire()
+ # Must reacquire lock even if wait is cancelled
+ while True:
+ try:
+ yield from self.acquire()
+ break
+ except futures.CancelledError:
+ pass
@coroutine
def wait_for(self, predicate):
diff --git a/Lib/test/test_asyncio/test_locks.py b/Lib/test/test_asyncio/test_locks.py
index cdf5d9d..d3bdc51 100644
--- a/Lib/test/test_asyncio/test_locks.py
+++ b/Lib/test/test_asyncio/test_locks.py
@@ -457,6 +457,31 @@
self.assertFalse(cond._waiters)
self.assertTrue(cond.locked())
+ def test_wait_cancel_contested(self):
+ cond = asyncio.Condition(loop=self.loop)
+
+ self.loop.run_until_complete(cond.acquire())
+ self.assertTrue(cond.locked())
+
+ wait_task = asyncio.Task(cond.wait(), loop=self.loop)
+ test_utils.run_briefly(self.loop)
+ self.assertFalse(cond.locked())
+
+ # Notify, but contest the lock before cancelling
+ self.loop.run_until_complete(cond.acquire())
+ self.assertTrue(cond.locked())
+ cond.notify()
+ self.loop.call_soon(wait_task.cancel)
+ self.loop.call_soon(cond.release)
+
+ try:
+ self.loop.run_until_complete(wait_task)
+ except asyncio.CancelledError:
+ # Should not happen, since no cancellation points
+ pass
+
+ self.assertTrue(cond.locked())
+
def test_wait_unacquired(self):
cond = asyncio.Condition(loop=self.loop)
self.assertRaises(