local_attr_ancestors fallbacks to using .ancestors if .mro() fails.

2 files changed, 11 insertions, 4 deletions

diff --git a/astroid/scoped_nodes.py b/astroid/scoped_nodes.py
index 0a4f9b6..626d8f8 100644
--- a/astroid/scoped_nodes.py
+++ b/astroid/scoped_nodes.py
@@ -1150,9 +1150,9 @@ class Class(Statement, LocalsDictNodeNG, FilterStmtsMixin):
             try:
                 ancestors = self.mro(context)[1:]
             except MroError:
-                # Reraise it as NotFoundError, there's no reason
-                # for MroError to leak out.
-                six.raise_from(NotFoundError, MroError)
+                # Fallback to use ancestors, we can't determine
+                # a sane MRO.
+                ancestors = self.ancestors(context=context)
         else:
             ancestors = self.ancestors(context=context)
         for astroid in ancestors:
diff --git a/astroid/tests/unittest_scoped_nodes.py b/astroid/tests/unittest_scoped_nodes.py
index 2bc3254..cd41dc4 100644
--- a/astroid/tests/unittest_scoped_nodes.py
+++ b/astroid/tests/unittest_scoped_nodes.py
@@ -1348,10 +1348,17 @@ class ClassNodeTest(ModuleLoader, unittest.TestCase):
 
     def test_local_attr_invalid_mro(self):
         cls = test_utils.extract_node("""
+        # A has an invalid MRO, local_attr should fallback
+        # to using .ancestors.
         class A(object, object):
+            test = 42
+        class B(A): #@
             pass
         """)
-        self.assertRaises(NotFoundError, cls.local_attr, 'test')
+        local = cls.local_attr('test')[0]
+        inferred = next(local.infer())
+        self.assertIsInstance(inferred, nodes.Const)
+        self.assertEqual(inferred.value, 42)         
 
     def test_has_dynamic_getattr(self):
         module = test_utils.build_module("""