diff -r 3e49127bcec3 -r 9d023ef7b467 mercurial/changelog.py
--- a/mercurial/changelog.py	Wed Sep 10 22:37:07 2008 +0200
+++ b/mercurial/changelog.py	Sat Sep 13 17:46:09 2008 +0200
@@ -6,7 +6,8 @@
 # of the GNU General Public License, incorporated herein by reference.
 
 from node import bin, hex, nullid
-from revlog import revlog
+from revlog import revlog, RevlogError
+from i18n import _
 import util
 
 def _string_escape(text):
@@ -178,6 +179,9 @@
     def add(self, manifest, list, desc, transaction, p1=None, p2=None,
                   user=None, date=None, extra={}):
 
+        user = user.strip()
+        if "\n" in user:
+            raise RevlogError(_("username %s contains a newline") % `user`)
         user, desc = util.fromlocal(user), util.fromlocal(desc)
 
         if date: