From 332709f9ee013e22bcdd3a0eae03c44c1da9ddd6 Mon Sep 17 00:00:00 2001
From: Andrey Vlasovskikh <andrey.vlasovskikh@jetbrains.com>
Date: Tue, 17 Feb 2015 16:46:35 +0300
Subject: [PATCH] Fixed SOE in PyClass.isOverriddenMRO() check (PY-15002)

In Python 2 it is possible to create an endless metaclass chain by
defining '__metaclass__' at the top-level to be one of the classes
defined in the module. We assume that these circular metaclasses don't
override `mro()` in order to prevent infinite recursion in this check.
---
 .../com/jetbrains/python/psi/impl/PyClassImpl.java    |  3 +++
 .../incorrectFileLevelMetaclass.py                    | 11 +++++++++++
 .../PyUnresolvedReferencesInspectionTest.java         |  5 +++++
 3 files changed, 19 insertions(+)
 create mode 100644 python/testData/inspections/PyUnresolvedReferencesInspection/incorrectFileLevelMetaclass.py

diff --git a/python/src/com/jetbrains/python/psi/impl/PyClassImpl.java b/python/src/com/jetbrains/python/psi/impl/PyClassImpl.java
index 29e590bac898..33c7a7a40339 100644
--- a/python/src/com/jetbrains/python/psi/impl/PyClassImpl.java
+++ b/python/src/com/jetbrains/python/psi/impl/PyClassImpl.java
@@ -1359,6 +1359,9 @@ public class PyClassImpl extends PyBaseElementImpl<PyClassStub> implements PyCla
       final PyType metaClassType = cls.getMetaClassType(context);
       if (metaClassType instanceof PyClassType) {
         final PyClass metaClass = ((PyClassType)metaClassType).getPyClass();
+        if (cls == metaClass) {
+          return false;
+        }
         final PyFunction mroMethod = metaClass.findMethodByName(PyNames.MRO, true);
         if (mroMethod != null) {
           final PyClass mroClass = mroMethod.getContainingClass();
diff --git a/python/testData/inspections/PyUnresolvedReferencesInspection/incorrectFileLevelMetaclass.py b/python/testData/inspections/PyUnresolvedReferencesInspection/incorrectFileLevelMetaclass.py
new file mode 100644
index 000000000000..0e55981c2db4
--- /dev/null
+++ b/python/testData/inspections/PyUnresolvedReferencesInspection/incorrectFileLevelMetaclass.py
@@ -0,0 +1,11 @@
+class __metaclass__(object):
+    pass
+
+
+class C(object):
+    def foo(self):
+        pass
+
+
+c = C()
+c.foo()
diff --git a/python/testSrc/com/jetbrains/python/inspections/PyUnresolvedReferencesInspectionTest.java b/python/testSrc/com/jetbrains/python/inspections/PyUnresolvedReferencesInspectionTest.java
index 327cecabf147..9013d0952934 100644
--- a/python/testSrc/com/jetbrains/python/inspections/PyUnresolvedReferencesInspectionTest.java
+++ b/python/testSrc/com/jetbrains/python/inspections/PyUnresolvedReferencesInspectionTest.java
@@ -460,6 +460,11 @@ public class PyUnresolvedReferencesInspectionTest extends PyInspectionTestCase {
     doTest();
   }
 
+  // PY-15002
+  public void testIncorrectFileLevelMetaclass() {
+    doTest();
+  }
+
   @NotNull
   @Override
   protected Class<? extends PyInspection> getInspectionClass() {