Revert #893: Avoid setting a Call as a base for metaclasses from six.with_metaclass() (#1622)

Author: jacobtylerwalls

ChangeLog

@@ -8,6 +8,10 @@ Release date: TBA
 
 * ``astroid`` now requires Python 3.7.2 to run.
 
+* Avoid setting a Call as a base for classes created using ``six.with_metaclass()``.
+
+  Refs PyCQA/pylint#5935
+
 * Fix detection of builtins on ``PyPy`` 3.9.
 
 * Fix ``re`` brain on Python ``3.11``. The flags now come from ``re._compile``.

astroid/brain/brain_six.py

@@ -219,6 +219,7 @@ def transform_six_with_metaclass(node):
     """
     call = node.bases[0]
     node._metaclass = call.args[0]
+    node.bases = call.args[1:]
     return node
 
 

tests/unittest_brain.py

@@ -569,13 +569,29 @@ class B(six.with_metaclass(A, C)):
         inferred = next(ast_node.infer())
         self.assertIsInstance(inferred, nodes.ClassDef)
         self.assertEqual(inferred.name, "B")
-        self.assertIsInstance(inferred.bases[0], nodes.Call)
+        self.assertIsInstance(inferred.bases[0], nodes.Name)
+        self.assertEqual(inferred.bases[0].name, "C")
         ancestors = tuple(inferred.ancestors())
         self.assertIsInstance(ancestors[0], nodes.ClassDef)
         self.assertEqual(ancestors[0].name, "C")
         self.assertIsInstance(ancestors[1], nodes.ClassDef)
         self.assertEqual(ancestors[1].name, "object")
 
+    @staticmethod
+    def test_six_with_metaclass_enum_ancestor() -> None:
+        code = """
+        import six
+        from enum import Enum, EnumMeta
+
+        class FooMeta(EnumMeta):
+            pass
+
+        class Foo(six.with_metaclass(FooMeta, Enum)):  #@
+            bar = 1
+        """
+        klass = astroid.extract_node(code)
+        assert list(klass.ancestors())[-1].name == "Enum"
+
     def test_six_with_metaclass_with_additional_transform(self) -> None:
         def transform_class(cls: Any) -> ClassDef:
             if cls.name == "A":