[3.5] bpo-30775: Fix refleaks in test_multiprocessing (GH-2467) (#2469)

Forgetting to call Process.join() can keep some resources alive.
(cherry picked from commit a79f8faccf5e26f55e8b9496ad49d2071b5e299c)

diff --git a/Lib/test/_test_multiprocessing.py b/Lib/test/_test_multiprocessing.py
index 01459dc81d86df5c713ce832acfd5203f381c5f5..76209f134330a14e0a7a1c5d2ac9d20fb5dc6152 100644 (file)
--- a/Lib/test/_test_multiprocessing.py
+++ b/Lib/test/_test_multiprocessing.py
@@ -1181,10 +1181,19 @@ class Bunch(object):
         self._can_exit = namespace.Event()
         if not wait_before_exit:
             self._can_exit.set()
+
+        threads = []
         for i in range(n):
             p = namespace.Process(target=self.task)
             p.daemon = True
             p.start()
+            threads.append(p)
+
+        def finalize(threads):
+            for p in threads:
+                p.join()
+
+        self._finalizer = weakref.finalize(self, finalize, threads)
 
     def task(self):
         pid = os.getpid()
@@ -1207,6 +1216,9 @@ class Bunch(object):
     def do_finish(self):
         self._can_exit.set()
 
+    def close(self):
+        self._finalizer()
+
 
 class AppendTrue(object):
     def __init__(self, obj):
@@ -1239,8 +1251,11 @@ class _TestBarrier(BaseTestCase):
 
     def run_threads(self, f, args):
         b = Bunch(self, f, args, self.N-1)
-        f(*args)
-        b.wait_for_finished()
+        try:
+            f(*args)
+            b.wait_for_finished()
+        finally:
+            b.close()
 
     @classmethod
     def multipass(cls, barrier, results, n):