gh-107431: Make multiprocessing.managers.{DictProxy,ListProxy} generic

Lib/multiprocessing/managers.py

@@ -1159,16 +1159,21 @@ def __imul__(self, value):
         self._callmethod('__imul__', (value,))
         return self
 
+    __class_getitem__ = classmethod(types.GenericAlias)
+
 
-DictProxy = MakeProxyType('DictProxy', (
+BaseDictProxy = MakeProxyType('DictProxy', (
     '__contains__', '__delitem__', '__getitem__', '__iter__', '__len__',
     '__setitem__', 'clear', 'copy', 'get', 'items',
-    'keys', 'pop', 'popitem', 'setdefault', 'update', 'values'
+    'keys', 'pop', 'popitem', 'setdefault', 'update', 'values',
     ))
-DictProxy._method_to_typeid_ = {
-    '__iter__': 'Iterator',
+class DictProxy(BaseDictProxy):
+    _method_to_typeid_ = {
+        '__iter__': 'Iterator',
     }
 
+    __class_getitem__ = classmethod(types.GenericAlias)
+
 
 ArrayProxy = MakeProxyType('ArrayProxy', (
     '__len__', '__getitem__', '__setitem__'

Lib/test/test_genericalias.py

@@ -28,14 +28,16 @@
 from itertools import chain
 from http.cookies import Morsel
 try:
-    from multiprocessing.managers import ValueProxy
+    from multiprocessing.managers import ValueProxy, DictProxy, ListProxy
     from multiprocessing.pool import ApplyResult
     from multiprocessing.queues import SimpleQueue as MPSimpleQueue
     from multiprocessing.queues import Queue as MPQueue
     from multiprocessing.queues import JoinableQueue as MPJoinableQueue
 except ImportError:
     # _multiprocessing module is optional
     ValueProxy = None
+    DictProxy = None
+    ListProxy = None
     ApplyResult = None
     MPSimpleQueue = None
     MPQueue = None
@@ -134,7 +136,7 @@ class BaseTest(unittest.TestCase):
     if ctypes is not None:
         generic_types.extend((ctypes.Array, ctypes.LibraryLoader))
     if ValueProxy is not None:
-        generic_types.extend((ValueProxy, ApplyResult,
+        generic_types.extend((ValueProxy, DictProxy, ListProxy, ApplyResult,
                               MPSimpleQueue, MPQueue, MPJoinableQueue))
 
     def test_subscriptable(self):

Misc/NEWS.d/next/Library/2023-07-29-19-00-39.gh-issue-107431.1GzJ2p.rst

@@ -0,0 +1,2 @@
+Make ``DictProxy`` and ``ListProxy`` types in ``multiprocessing.managers``
+generic.