bpo-36813: Fix QueueListener to call task_done() upon termination. (GH-13113)
Fixed QueueListener in order to avoid random deadlocks.
Unable to add regression tests atm due to time constraints, will add it in a bit.
Regarding implementation, although it's nested, it does not cause performance issues whatsoever, and does not call task_done() in case of an exception (which is the right thing to do IMHO).
https://bugs.python.org/issue36813
diff --git a/Lib/test/test_logging.py b/Lib/test/test_logging.py
index b884753..50148dc 100644
--- a/Lib/test/test_logging.py
+++ b/Lib/test/test_logging.py
@@ -3633,6 +3633,16 @@
[m.msg if isinstance(m, logging.LogRecord)
else m for m in items]))
+ def test_calls_task_done_after_stop(self):
+ # Issue 36813: Make sure queue.join does not deadlock.
+ log_queue = queue.Queue()
+ listener = logging.handlers.QueueListener(log_queue)
+ listener.start()
+ listener.stop()
+ with self.assertRaises(ValueError):
+ # Make sure all tasks are done and .join won't block.
+ log_queue.task_done()
+
ZERO = datetime.timedelta(0)