GH-103699: Add __orig_bases__ to various typing classes

Lib/test/test_typing.py

@@ -7126,6 +7126,46 @@ class TD(TypedDict):
         self.assertIs(type(a), dict)
         self.assertEqual(a, {'a': 1})
 
+    def test_orig_bases(self):
+        T = TypeVar('T')
+
+        class Parent(TypedDict):
+            pass
+
+        class Child(Parent):
+            pass
+
+        class OtherChild(Parent):
+            pass
+
+        class MixedChild(Child, OtherChild, Parent):
+            pass
+
+        class GenericParent(TypedDict, Generic[T]):
+            pass
+
+        class GenericChild(GenericParent[int]):
+            pass
+
+        class OtherGenericChild(GenericParent[str]):
+            pass
+
+        class MixedGenericChild(GenericChild, OtherGenericChild, GenericParent[float]):
+            pass
+
+        class MultipleGenericBases(GenericParent[int], GenericParent[float]):
+            pass
+
+        self.assertEqual(Parent.__orig_bases__, (TypedDict,))
+        self.assertEqual(Child.__orig_bases__, (Parent,))
+        self.assertEqual(OtherChild.__orig_bases__, (Parent,))
+        self.assertEqual(MixedChild.__orig_bases__, (Child, OtherChild, Parent,))
+        self.assertEqual(GenericParent.__orig_bases__, (TypedDict, Generic[T]))
+        self.assertEqual(GenericChild.__orig_bases__, (GenericParent[int],))
+        self.assertEqual(OtherGenericChild.__orig_bases__, (GenericParent[str],))
+        self.assertEqual(MixedGenericChild.__orig_bases__, (GenericChild, OtherGenericChild, GenericParent[float]))
+        self.assertEqual(MultipleGenericBases.__orig_bases__, (GenericParent[int], GenericParent[float]))
+
 
 class RequiredTests(BaseTestCase):
 

Lib/typing.py

@@ -2994,6 +2994,9 @@ def __new__(cls, name, bases, ns, total=True):
 
         tp_dict = type.__new__(_TypedDictMeta, name, (*generic_base, dict), ns)
 
+        if not hasattr(tp_dict, '__orig_bases__'):
+            tp_dict.__orig_bases__ = bases
+
         annotations = {}
         own_annotations = ns.get('__annotations__', {})
         msg = "TypedDict('Name', {f0: t0, f1: t1, ...}); each t must be a type"

Misc/NEWS.d/next/Library/2023-04-22-22-37-39.gh-issue-103699.NizCjc.rst

@@ -0,0 +1 @@
+Add ``__orig_bases__`` to non-generic TypedDicts