From: Kyle Stanley Date: Sun, 12 Jan 2020 11:02:50 +0000 (-0500) Subject: bpo-38356: Fix ThreadedChildWatcher thread leak in test_asyncio (GH-16552) X-Git-Tag: v3.9.0a3~95 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=0ca7cc7fc0518c24dc9b78c38418e6064e64f148;p=thirdparty%2FPython%2Fcpython.git bpo-38356: Fix ThreadedChildWatcher thread leak in test_asyncio (GH-16552) Motivation for this PR (comment from @vstinner in bpo issue): ``` Warning seen o AMD64 Ubuntu Shared 3.x buildbot: https://buildbot.python.org/all/#/builders/141/builds/2593 test_devnull_output (test.test_a=syncio.test_subprocess.SubprocessThreadedWatcherTests) ... Warning -- threading_cleanup() failed to cleanup 1 threads (count: 1, dangling: 2) ``` The following implementation details for the new method are TBD: 1) Public vs private 2) Inclusion in `close()` 3) Name 4) Coroutine vs subroutine method 5) *timeout* parameter If it's a private method, 3, 4, and 5 are significantly less important. I started with the most minimal implementation that fixes the dangling threads without modifying the regression tests, which I think is particularly important. I typically try to avoid directly modifying existing tests as much as possible unless it's necessary to do so. However, I am open to changing any part of this. https://bugs.python.org/issue38356 --- diff --git a/Lib/asyncio/unix_events.py b/Lib/asyncio/unix_events.py index 28fb49186451..19d713545e4c 100644 --- a/Lib/asyncio/unix_events.py +++ b/Lib/asyncio/unix_events.py @@ -1344,7 +1344,14 @@ class ThreadedChildWatcher(AbstractChildWatcher): return True def close(self): - pass + self._join_threads() + + def _join_threads(self): + """Internal: Join all non-daemon threads""" + threads = [thread for thread in list(self._threads.values()) + if thread.is_alive() and not thread.daemon] + for thread in threads: + thread.join() def __enter__(self): return self