diff -r 813db1dccc05 -r f88ca484c3e9 mercurial/commands.py
--- a/mercurial/commands.py	Wed Oct 17 22:25:41 2012 -0500
+++ b/mercurial/commands.py	Wed Oct 17 16:23:42 2012 -0500
@@ -790,8 +790,6 @@
     cur   = repo.changectx('.').node()
 
     def checkformat(mark):
-        if "\n" in mark:
-            raise util.Abort(_("bookmark name cannot contain newlines"))
         mark = mark.strip()
         if not mark:
             raise util.Abort(_("bookmark names cannot consist entirely of "