hgext/rebase.py

--- a/hgext/rebase.py	Wed Mar 23 02:33:24 2011 +0100
+++ b/hgext/rebase.py	Wed Mar 23 01:14:43 2011 +0100
@@ -482,9 +482,10 @@
 
     if src:
         commonbase = repo[src].ancestor(repo[dest])
+        samebranch = repo[src].branch() == repo[dest].branch()
         if commonbase == repo[src]:
             raise util.Abort(_('source is ancestor of destination'))
-        if commonbase == repo[dest]:
+        if samebranch and commonbase == repo[dest]:
             raise util.Abort(_('source is descendant of destination'))
         source = repo[src].rev()
         if detach: