From 10f57795ecd420e1ff1c5b7f15089b4209847623 Mon Sep 17 00:00:00 2001 From: Victor Stinner Date: Wed, 26 Jul 2017 02:32:42 +0200 Subject: [PATCH] bpo-31019: Fix multiprocessing.Process.is_alive() (#2875) multiprocessing.Process.is_alive() now removes the process from the _children set if the process completed. The change prevents leaking "dangling" processes. (cherry picked from commit 2db64823c20538a6cfc6033661fab5711d2d4585) --- Lib/multiprocessing/process.py | 10 ++++++++-- 1 file changed, 8 insertions(+), 2 deletions(-) diff --git a/Lib/multiprocessing/process.py b/Lib/multiprocessing/process.py index 16c4e1eb343736..11c8fca360fa22 100644 --- a/Lib/multiprocessing/process.py +++ b/Lib/multiprocessing/process.py @@ -156,10 +156,16 @@ def is_alive(self): if self is _current_process: return True assert self._parent_pid == os.getpid(), 'can only test a child process' + if self._popen is None: return False - self._popen.poll() - return self._popen.returncode is None + + returncode = self._popen.poll() + if returncode is None: + return True + else: + _current_process._children.discard(self) + return False @property def name(self):