diff -r 0b450267cf47 -r ef1032c223e7 mercurial/sshserver.py
--- a/mercurial/sshserver.py	Sat Sep 09 18:25:06 2006 -0700
+++ b/mercurial/sshserver.py	Sat Sep 09 18:25:06 2006 -0700
@@ -51,7 +51,13 @@
     def do_lookup(self):
         arg, key = self.getarg()
         assert arg == 'key'
-        self.respond(hex(self.repo.lookup(key)) + "\n")
+        try:
+            r = hex(self.repo.lookup(key))
+            success = 1
+        except Exception,inst:
+            r = str(inst)
+            success = 0
+        self.respond("%s %s\n" % (success, r))
 
     def do_heads(self):
         h = self.repo.heads()