Fix checking open() modes on python3

open.__module__ is io, not __builtins__.

1 files changed, 11 insertions, 4 deletions

diff --git a/checkers/stdlib.py b/checkers/stdlib.py
index 364633b74..604ade8ac 100644
--- a/checkers/stdlib.py
+++ b/checkers/stdlib.py
@@ -16,6 +16,7 @@
 """Checkers for various standard library functions."""
 
 import re
+import sys
 
 import astroid
 
@@ -25,7 +26,11 @@ from pylint.checkers import utils
 
 _VALID_OPEN_MODE_REGEX = r'^(r?U|[rwa]\+?b?)$'
 
-
+if sys.version_info >= (3, 0):
+    OPEN_MODULE = '_io'
+else:
+    OPEN_MODULE = '__builtins__'
+ 
 class OpenModeChecker(BaseChecker):
     __implements__ = (IAstroidChecker,)
     name = 'open_mode'
@@ -40,9 +45,11 @@ class OpenModeChecker(BaseChecker):
     @utils.check_messages('W1501')
     def visit_callfunc(self, node):
         """Visit a CallFunc node."""
-        if (hasattr(node, 'func') and utils.is_builtin_object(utils.safe_infer(node.func))):
-            if getattr(node.func, 'name', None) in ('open', 'file'):
-                self._check_open_mode(node)
+        if hasattr(node, 'func'):
+            infer = utils.safe_infer(node.func)
+            if infer and infer.root().name == OPEN_MODULE:
+                if getattr(node.func, 'name', None) in ('open', 'file'):
+                    self._check_open_mode(node)
 
     def _check_open_mode(self, node):
         """Check that the mode argument of an open or file call is valid."""