diff -r 67964cda8701 -r e34106fa0dc3 hgext/convert/git.py
--- a/hgext/convert/git.py	Sat May 12 16:00:57 2012 +0200
+++ b/hgext/convert/git.py	Sat May 12 16:00:58 2012 +0200
@@ -69,7 +69,7 @@
 
     def catfile(self, rev, type):
         if rev == hex(nullid):
-            raise IOError()
+            raise IOError
         data, ret = self.gitread("git cat-file %s %s" % (type, rev))
         if ret:
             raise util.Abort(_('cannot read %r object at %s') % (type, rev))