diff -r 9ac56d36d6ff -r 23ef1c71d164 hgext/obsolete.py
--- a/hgext/obsolete.py	Tue Jun 26 11:33:39 2012 +0200
+++ b/hgext/obsolete.py	Mon Jun 25 15:18:47 2012 +0200
@@ -468,6 +468,9 @@
         if ctx.obsolete():
             raise util.Abort(_("Trying to push obsolete changeset: %s!") % ctx,
                              hint=hint)
+        if ctx.latecomer():
+            raise util.Abort(_("Trying to push latecomer changeset: %s!") % ctx,
+                             hint=hint)
     ### patch remote branch map
     # do not read it this burn eyes
     try: