Issue #16481: Merge

3 files changed, 17 insertions, 16 deletions

diff --git a/Lib/multiprocessing/__init__.py b/Lib/multiprocessing/__init__.py
index 1f3e67c9b8..efad532be1 100644
--- a/Lib/multiprocessing/__init__.py
+++ b/Lib/multiprocessing/__init__.py
@@ -40,6 +40,13 @@ from multiprocessing.process import Process, current_process, active_children
 from multiprocessing.util import SUBDEBUG, SUBWARNING
 
 #
+# Alias for main module -- will be reset by bootstrapping child processes
+#
+
+if '__main__' in sys.modules:
+    sys.modules['__mp_main__'] = sys.modules['__main__']
+
+#
 # Exceptions
 #
 
diff --git a/Lib/multiprocessing/forking.py b/Lib/multiprocessing/forking.py
index c5501a2f75..a0b3d68f9f 100644
--- a/Lib/multiprocessing/forking.py
+++ b/Lib/multiprocessing/forking.py
@@ -442,27 +442,17 @@ def prepare(data):
                 dirs = [os.path.dirname(main_path)]
 
             assert main_name not in sys.modules, main_name
+            sys.modules.pop('__mp_main__', None)
             file, path_name, etc = imp.find_module(main_name, dirs)
             try:
-                # We would like to do "imp.load_module('__main__', ...)"
-                # here.  However, that would cause 'if __name__ ==
-                # "__main__"' clauses to be executed.
+                # We should not do 'imp.load_module("__main__", ...)'
+                # since that would execute 'if __name__ == "__main__"'
+                # clauses, potentially causing a psuedo fork bomb.
                 main_module = imp.load_module(
-                    '__parents_main__', file, path_name, etc
+                    '__mp_main__', file, path_name, etc
                     )
             finally:
                 if file:
                     file.close()
 
-            sys.modules['__main__'] = main_module
-            main_module.__name__ = '__main__'
-
-            # Try to make the potentially picklable objects in
-            # sys.modules['__main__'] realize they are in the main
-            # module -- somewhat ugly.
-            for obj in list(main_module.__dict__.values()):
-                try:
-                    if obj.__module__ == '__parents_main__':
-                        obj.__module__ = '__main__'
-                except Exception:
-                    pass
+            sys.modules['__main__'] = sys.modules['__mp_main__'] = main_module
diff --git a/Lib/multiprocessing/queues.py b/Lib/multiprocessing/queues.py
index 37271fb4eb..f6f02b6665 100644
--- a/Lib/multiprocessing/queues.py
+++ b/Lib/multiprocessing/queues.py
@@ -243,10 +243,14 @@ class Queue(object):
 
                         if wacquire is None:
                             send(obj)
+                            # Delete references to object. See issue16284
+                            del obj
                         else:
                             wacquire()
                             try:
                                 send(obj)
+                                # Delete references to object. See issue16284
+                                del obj
                             finally:
                                 wrelease()
                 except IndexError: