Fallback to __bases__

Gobot1234 · Gobot1234 · commit 6f06c526e854 · 2023-04-09T19:37:16.000+01:00
diff --git a/Lib/test/test_types.py b/Lib/test/test_types.py
@@ -1366,10 +1366,10 @@ class A: pass
         class B(typing.Generic[T]): pass
         class C(B[int]): pass
         class D(B[str], float): pass
-        self.assertIsNone(types.get_original_bases(A))
+        self.assertEqual(types.get_original_bases(A), (object,))
         self.assertEqual(types.get_original_bases(B), (typing.Generic[T],))
         self.assertEqual(types.get_original_bases(C), (B[int],))
-        self.assertIsNone(types.get_original_bases(int))
+        self.assertEqual(types.get_original_bases(int), (object,))
         self.assertEqual(types.get_original_bases(D), (B[str], float))
 
         class E(list[T]): pass
@@ -1383,6 +1383,9 @@ class G(typing.NamedTuple):
 
         self.assertIs(types.get_original_bases(G)[0], typing.NamedTuple)
 
+        with self.assertRaises(TypeError):
+            types.get_original_bases(object())
+
     # Many of the following tests are derived from test_descr.py
     def test_prepare_class(self):
         # Basic test of metaclass derivation
diff --git a/Lib/types.py b/Lib/types.py
@@ -163,12 +163,15 @@ class Baz(list[str]): ...
         get_original_bases(Baz) == (list[str],)
         get_original_bases(int) == None
     """
-    if isinstance(cls, type):
+    try:
+        return cls.__orig_bases__
+    except AttributeError:
         try:
-            return cls.__orig_bases__
+            return cls.__bases__
         except AttributeError:
-            pass
-    return None
+            raise TypeError(
+                f'Expected an instance of type, not {type(cls).__name__!r}'
+            ) from None
 
 
 class DynamicClassAttribute:
