[Python-checkins] cpython (3.2): Issue #12364: Fix a hang in concurrent.futures.ProcessPoolExecutor.

Sun Jan 8 07:43:53 CET 2012

http://hg.python.org/cpython/rev/26389e9efa9c
changeset: 74299:26389e9efa9c
branch: 3.2
parent: 74295:69527695eff8
user: Ross Lagerwall <rosslagerwall at gmail.com>
date: Sun Jan 08 08:29:40 2012 +0200
summary:
 Issue #12364: Fix a hang in concurrent.futures.ProcessPoolExecutor.
files:
 Lib/concurrent/futures/process.py | 7 +------
 Lib/test/test_concurrent_futures.py | 6 ++++++
 Misc/NEWS | 4 ++++
 3 files changed, 11 insertions(+), 6 deletions(-)

diff --git a/Lib/concurrent/futures/process.py b/Lib/concurrent/futures/process.py
--- a/Lib/concurrent/futures/process.py
+++ b/Lib/concurrent/futures/process.py
@@ -213,9 +213,7 @@
 work_item.future.set_exception(result_item.exception)
 else:
 work_item.future.set_result(result_item.result)
- continue
- # If we come here, we either got a timeout or were explicitly woken up.
- # In either case, check whether we should start shutting down.
+ # Check whether we should start shutting down.
 executor = executor_reference()
 # No more work items can be added if:
 # - The interpreter is shutting down OR
@@ -234,9 +232,6 @@
 p.join()
 call_queue.close()
 return
- else:
- # Start shutting down by telling a process it can exit.
- shutdown_one_process()
 del executor
 
 _system_limits_checked = False
diff --git a/Lib/test/test_concurrent_futures.py b/Lib/test/test_concurrent_futures.py
--- a/Lib/test/test_concurrent_futures.py
+++ b/Lib/test/test_concurrent_futures.py
@@ -109,6 +109,12 @@
 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
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -97,6 +97,10 @@
 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.
 
-- 
Repository URL: http://hg.python.org/cpython
