commit 713b4bbd97392acc492a4fefb2d07ae61fb7b75d
author Miss Islington (bot) <31488909+miss-islington@users.noreply.github.com> Sat Nov 21 01:46:21 2020 -0800
committer GitHub <noreply@github.com> Sat Nov 21 01:46:21 2020 -0800
tree 30d3c2270e96cc908c5c9cf1a9d3da01871bc87e
parent c1bbca5b004b3f74d240ef8a76ff445cc1a27efb

bpo-40550: Fix time-of-check/time-of-action issue in subprocess.Popen.send_signal. (GH-20010)


send_signal() now swallows the exception if the process it thought was still alive winds up not to exist anymore (always a plausible race condition despite the checks).

Co-authored-by: Gregory P. Smith <greg@krypto.org>
(cherry picked from commit 01a202ab6b0ded546e47073db6498262086c52e9)

Co-authored-by: Filipe Laíns <lains@archlinux.org>

Lib/subprocess.py

diff --git a/Lib/subprocess.py b/Lib/subprocess.py
index 13600c2..f1d829a 100644
--- a/Lib/subprocess.py
+++ b/Lib/subprocess.py
@@ -2061,7 +2061,11 @@
             # The race condition can still happen if the race condition
             # described above happens between the returncode test
             # and the kill() call.
-            os.kill(self.pid, sig)
+            try:
+                os.kill(self.pid, sig)
+            except ProcessLookupError:
+                # Supress the race condition error; bpo-40550.
+                pass
 
         def terminate(self):
             """Terminate the process with SIGTERM