Fix attributes of ancestor classes from appearing in attribute inference

Close #581

3 files changed, 33 insertions, 10 deletions

diff --git a/astroid/bases.py b/astroid/bases.py
index c7b0cbc3..caf230f1 100644
--- a/astroid/bases.py
+++ b/astroid/bases.py
@@ -343,9 +343,7 @@ class UnboundMethod(Proxy):
         # instance of the class given as first argument.
         if (self._proxied.name == '__new__' and
                 self._proxied.parent.frame().qname() == '%s.object' % BUILTINS):
-            # XXX Avoid issue with type.__new__ inference.
-            # https://github.com/PyCQA/astroid/issues/581
-            if caller.args and len(caller.args) == 1:
+            if caller.args:
                 node_context = context.extra_context.get(caller.args[0])
                 infer = caller.args[0].infer(context=node_context)
             else:
@@ -440,10 +438,7 @@ class BoundMethod(UnboundMethod):
         if (self.bound.__class__.__name__ == 'ClassDef'
                 and self.bound.name == 'type'
                 and self.name == '__new__'
-                and len(caller.args) == 4
-                # TODO(cpopa): this check shouldn't be needed.
-                and self._proxied.parent.frame().qname() == '%s.object' % BUILTINS):
-
+                and len(caller.args) == 4):
             # Check if we have an ``type.__new__(mcs, name, bases, attrs)`` call.
             new_cls = self._infer_type_new_call(caller, context)
             if new_cls:
diff --git a/astroid/scoped_nodes.py b/astroid/scoped_nodes.py
index 1eef1416..3b1cc50a 100644
--- a/astroid/scoped_nodes.py
+++ b/astroid/scoped_nodes.py
@@ -2366,8 +2366,8 @@ class ClassDef(mixins.FilterStmtsMixin, LocalsDictNodeNG,
         context = contextmod.copy_context(context)
         context.lookupname = name
         try:
-            attrs = self.getattr(name, context, class_context=class_context)
-            for inferred in bases._infer_stmts(attrs, context, frame=self):
+            attr = self.getattr(name, context, class_context=class_context)[0]
+            for inferred in bases._infer_stmts([attr], context, frame=self):
                 # yield Uninferable object instead of descriptors when necessary
                 if (not isinstance(inferred, node_classes.Const)
                         and isinstance(inferred, bases.Instance)):
diff --git a/astroid/tests/unittest_inference.py b/astroid/tests/unittest_inference.py
index 353ac23b..39f43435 100644
--- a/astroid/tests/unittest_inference.py
+++ b/astroid/tests/unittest_inference.py
@@ -3404,7 +3404,8 @@ class InferenceTest(resources.SysPathSetup, unittest.TestCase):
         ''')
         inferred = next(ast_node.infer())
         self.assertIsInstance(inferred, nodes.ClassDef)
-        titles = [title.value for title in inferred.igetattr('title')]
+        titles = [title.value for attr in inferred.getattr('title')
+                  for title in attr.inferred()]
         self.assertEqual(titles, ['Catch 22', 'Ubik', 'Grimus'])
 
     @unittest.expectedFailure
@@ -4684,5 +4685,32 @@ def test_limit_inference_result_amount():
     assert util.Uninferable in result_limited
 
 
+def test_attribute_inference_should_not_access_base_classes():
+    """attributes of classes should mask ancestor attribues"""
+    code = """
+    type.__new__ #@
+    """
+    res = extract_node(code).inferred()
+    assert len(res) == 1
+    assert res[0].parent.name == "type"
+
+
+def test_attribute_mro_object_inference():
+    """
+    Inference should only infer results from the first available method
+    """
+    inferred = extract_node("""
+    class A:
+        def foo(self):
+            return 1
+    class B(A):
+        def foo(self):
+            return 2
+    B().foo() #@
+    """).inferred()
+    assert len(inferred) == 1
+    assert inferred[0].value == 2
+
+
 if __name__ == '__main__':
     unittest.main()