--- a/mercurial/obsolete.py	Sat Jul 28 13:05:25 2012 +0200
+++ b/mercurial/obsolete.py	Sat Jul 28 13:33:06 2012 +0200
@@ -55,6 +55,10 @@
 from mercurial import util, base85
 from i18n import _
 
+# the obsolete feature is not mature enought to be enabled by default.
+# you have to rely on third party extension extension to enable this.
+_enabled = False
+
 _pack = struct.pack
 _unpack = struct.unpack