diff --git a/mercurial/demandimport.py b/mercurial/demandimport.py
--- a/mercurial/demandimport.py
+++ b/mercurial/demandimport.py
@@ -291,6 +291,8 @@ ignore = [
     'sqlalchemy.events', # has import-time side effects (issue5085)
     # setuptools 8 expects this module to explode early when not on windows
     'distutils.msvc9compiler',
+    '__builtin__',
+    'builtins',
     ]
 
 if _pypy: