diff mercurial/ui.py @ 8527:f9a80054dd3c

use 'x is None' instead of 'x == None'

The built-in None object is a singleton and it is therefore safe to
compare memory addresses with is. It is also faster, how much depends
on the object being compared. For a simple type like str I get:

            | s = "foo" | s = None
  ----------+-----------+----------
  s == None | 0.25 usec | 0.21 usec
  s is None | 0.17 usec | 0.17 usec

--- a/mercurial/ui.py	Wed May 20 00:43:23 2009 +0200
+++ b/mercurial/ui.py	Wed May 20 00:52:46 2009 +0200
@@ -129,7 +129,7 @@
 
     def configbool(self, section, name, default=False, untrusted=False):
         v = self.config(section, name, None, untrusted)
-        if v == None:
+        if v is None:
             return default
         if v.lower() not in _booleans:
             raise error.ConfigError(_("%s.%s not a boolean ('%s')")