From b469ab8802fa6e3e78ae712e773f262e23eebe90 Mon Sep 17 00:00:00 2001
From: Victor Stinner <victor.stinner@gmail.com>
Date: Mon, 24 Jul 2017 19:36:55 +0200
Subject: [PATCH] multiprocessing.Pool.terminate() joins all processes

bpo-31019: Pool.terminate() now also joins "dead" processes even if
their is_alive() method returns false. The change prevents leaking
"dangling" processes.
---
 Lib/multiprocessing/pool.py                                 | 6 ++----
 .../next/Library/2017-07-24-19-38-49.bpo-31019.Kk8H5i.rst   | 3 +++
 2 files changed, 5 insertions(+), 4 deletions(-)
 create mode 100644 Misc/NEWS.d/next/Library/2017-07-24-19-38-49.bpo-31019.Kk8H5i.rst

diff --git a/Lib/multiprocessing/pool.py b/Lib/multiprocessing/pool.py
index c2364ab186c3282..4e33793b91015f0 100644
--- a/Lib/multiprocessing/pool.py
+++ b/Lib/multiprocessing/pool.py
@@ -599,10 +599,8 @@ def _terminate_pool(cls, taskqueue, inqueue, outqueue, pool,
         if pool and hasattr(pool[0], 'terminate'):
             util.debug('joining pool workers')
             for p in pool:
-                if p.is_alive():
-                    # worker has not yet exited
-                    util.debug('cleaning up worker %d' % p.pid)
-                    p.join()
+                util.debug('cleaning up worker %d' % p.pid)
+                p.join()
 
     def __enter__(self):
         return self
diff --git a/Misc/NEWS.d/next/Library/2017-07-24-19-38-49.bpo-31019.Kk8H5i.rst b/Misc/NEWS.d/next/Library/2017-07-24-19-38-49.bpo-31019.Kk8H5i.rst
new file mode 100644
index 000000000000000..f2dd76741e13715
--- /dev/null
+++ b/Misc/NEWS.d/next/Library/2017-07-24-19-38-49.bpo-31019.Kk8H5i.rst
@@ -0,0 +1,3 @@
+multiprocessing.Pool.terminate() now also joins "dead" processes even if
+their is_alive() method returns false. The change prevents leaking
+"dangling" processes.