[3.6] bpo-28556: Update to typing: treat subscripted generics as proxies (GH-265) (GH-268)
(cherry picked from commit abb3b8ad94d699c8560d94ee9bac9c917b382abe)
(cherry picked from commit 365cb5bb9069273e6970c9d5d17ee2fe5003e7ac)
diff --git a/Lib/test/test_typing.py b/Lib/test/test_typing.py
index 64d8276..f0070ec 100644
--- a/Lib/test/test_typing.py
+++ b/Lib/test/test_typing.py
@@ -674,6 +674,41 @@
c.bar = 'abc'
self.assertEqual(c.__dict__, {'bar': 'abc'})
+ def test_subscripted_generics_as_proxies(self):
+ T = TypeVar('T')
+ class C(Generic[T]):
+ x = 'def'
+ self.assertEqual(C[int].x, 'def')
+ self.assertEqual(C[C[int]].x, 'def')
+ C[C[int]].x = 'changed'
+ self.assertEqual(C.x, 'changed')
+ self.assertEqual(C[str].x, 'changed')
+ C[List[str]].z = 'new'
+ self.assertEqual(C.z, 'new')
+ self.assertEqual(C[Tuple[int]].z, 'new')
+
+ self.assertEqual(C().x, 'changed')
+ self.assertEqual(C[Tuple[str]]().z, 'new')
+
+ class D(C[T]):
+ pass
+ self.assertEqual(D[int].x, 'changed')
+ self.assertEqual(D.z, 'new')
+ D.z = 'from derived z'
+ D[int].x = 'from derived x'
+ self.assertEqual(C.x, 'changed')
+ self.assertEqual(C[int].z, 'new')
+ self.assertEqual(D.x, 'from derived x')
+ self.assertEqual(D[str].z, 'from derived z')
+
+ def test_abc_registry_kept(self):
+ T = TypeVar('T')
+ class C(Generic[T]): ...
+ C.register(int)
+ self.assertIsInstance(1, C)
+ C[int]
+ self.assertIsInstance(1, C)
+
def test_false_subclasses(self):
class MyMapping(MutableMapping[str, str]): pass
self.assertNotIsInstance({}, MyMapping)
diff --git a/Lib/typing.py b/Lib/typing.py
index efe358f..9a0f490 100644
--- a/Lib/typing.py
+++ b/Lib/typing.py
@@ -1158,6 +1158,16 @@
self.__parameters__, self.__args__, self.__origin__,
self.__extra__, self.__orig_bases__)
+ def __setattr__(self, attr, value):
+ # We consider all the subscripted genrics as proxies for original class
+ if (
+ attr.startswith('__') and attr.endswith('__') or
+ attr.startswith('_abc_')
+ ):
+ super(GenericMeta, self).__setattr__(attr, value)
+ else:
+ super(GenericMeta, _gorg(self)).__setattr__(attr, value)
+
# Prevent checks for Generic to crash when defining Generic.
Generic = None