diff --git a/Lib/concurrent/futures/process.py b/Lib/concurrent/futures/process.py index 0575146b220..7f31ec2263b 100644 --- a/Lib/concurrent/futures/process.py +++ b/Lib/concurrent/futures/process.py @@ -273,9 +273,6 @@ def _queue_management_worker(executor_reference, if not pending_work_items: shutdown_worker() return - else: - # Start shutting down by telling a process it can exit. - call_queue.put_nowait(None) except Full: # This is not a problem: we will eventually be woken up (in # result_queue.get()) and be able to send a sentinel again. diff --git a/Lib/test/test_concurrent_futures.py b/Lib/test/test_concurrent_futures.py index 7522a54acbb..04ee246083e 100644 --- a/Lib/test/test_concurrent_futures.py +++ b/Lib/test/test_concurrent_futures.py @@ -109,6 +109,12 @@ class ExecutorShutdownTest(unittest.TestCase): self.assertFalse(err) self.assertEqual(out.strip(), b"apple") + def test_hang_issue12364(self): + fs = [self.executor.submit(time.sleep, 0.1) for _ in range(50)] + self.executor.shutdown() + for f in fs: + f.result() + class ThreadPoolShutdownTest(ThreadPoolMixin, ExecutorShutdownTest): def _prime_executor(self): diff --git a/Misc/NEWS b/Misc/NEWS index 05664f67679..fbc6f670a2a 100644 --- a/Misc/NEWS +++ b/Misc/NEWS @@ -422,6 +422,10 @@ Core and Builtins Library ------- +- Issue #12364: Fix a hang in concurrent.futures.ProcessPoolExecutor. + The hang would occur when retrieving the result of a scheduled future after + the executor had been shut down. + - Issue #13502: threading: Fix a race condition in Event.wait() that made it return False when the event was set and cleared right after.