The node.bases has not to be tweaked otherwise leads to false positive unused-import due to the fact that six.with_metaclass is not consumed. Adds a unittest to check that bases attribute holds a call node and that ancestors attributes returns the correct class hierarchy.

hippo91 · Pierre-Sassoulas · commit dc560d470b33 · 2021-02-12T08:26:52.000+01:00
diff --git a/astroid/brain/brain_six.py b/astroid/brain/brain_six.py
@@ -221,7 +221,6 @@ def transform_six_with_metaclass(node):
     """
     call = node.bases[0]
     node._metaclass = call.args[0]
-    node.bases = call.args[1:]
 
 
 register_module_extender(MANAGER, "six", six_moves_transform)
diff --git a/tests/unittest_inference.py b/tests/unittest_inference.py
@@ -3793,6 +3793,34 @@ class B(six.with_metaclass(A)):
         self.assertIsInstance(inferred, nodes.ClassDef)
         self.assertEqual(inferred.name, "B")
 
+    def test_With_metaclass_subclasses_inheritance(self):
+        ast_node = extract_node(
+            """
+        class A(type):
+            def test(cls):
+                return cls
+
+        class C:
+            pass
+
+        import six
+        class B(six.with_metaclass(A, C)):
+            pass
+
+        B #@
+        """
+        )
+        inferred = next(ast_node.infer())
+        self.assertIsInstance(inferred, nodes.ClassDef)
+        self.assertEqual(inferred.name, "B")
+        bases = inferred.bases
+        self.assertIsInstance(bases[0], nodes.Call)
+        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")
+
     def test_With_metaclass_with_partial_imported_name(self):
         ast_node = extract_node(
             """
