diff --git a/rhodecode/lib/__init__.py b/rhodecode/lib/__init__.py
--- a/rhodecode/lib/__init__.py
+++ b/rhodecode/lib/__init__.py
@@ -26,7 +26,16 @@
 # MA  02110-1301, USA.
 
 def str2bool(v):
-    return v.lower() in ["yes", "true", "t", "1"] if v else None
+    if isinstance(v, (str, unicode)):
+        obj = v.strip().lower()
+        if obj in ['true', 'yes', 'on', 'y', 't', '1']:
+            return True
+        elif obj in ['false', 'no', 'off', 'n', 'f', '0']:
+            return False
+        else:
+            if not safe:
+                raise ValueError("String is not true/false: %r" % obj)
+    return bool(obj)
 
 def generate_api_key(username, salt=None):
     from tempfile import _RandomNameSequence