diff -r fb83210bce32 -r c27a465daef2 hgext/obsolete.py
--- a/hgext/obsolete.py	Tue Jul 03 12:58:55 2012 +0200
+++ b/hgext/obsolete.py	Wed Jul 04 16:27:08 2012 +0200
@@ -856,10 +856,10 @@
         if metadata is None:
             metadata = {}
         if len(prec) != 20:
-            raise ValueError(prec)
+            raise ValueError(repr(prec))
         for succ in succs:
             if len(succ) != 20:
-                raise ValueError(prec)
+                raise ValueError((succs))
         marker = (str(prec), tuple(succs), int(flag), encodemeta(metadata))
         self.add(marker)