--- a/hgext/extdiff.py	Sun Feb 22 15:40:36 2015 +0100
+++ b/hgext/extdiff.py	Fri Feb 27 17:35:07 2015 -0500
@@ -276,6 +276,7 @@
 
 def uisetup(ui):
     for cmd, path in ui.configitems('extdiff'):
+        path = util.expandpath(path)
         if cmd.startswith('cmd.'):
             cmd = cmd[4:]
             if not path: