Index: trac/core.py
===================================================================
--- trac/core.py	(revision 8332)
+++ trac/core.py	(working copy)
@@ -33,11 +33,14 @@
         error message.
         """
         Exception.__init__(self, message)
-        self.message = message
+        self._message = message
         if title:
             self.title = title
         self.show_traceback = show_traceback
 
+    message = property(lambda self: self._message, 
+                       lambda self, v: setattr(self, '_message', v))
+
     def __unicode__(self):
         return unicode(self.message)