So using sys.excepthook to catch errors only works once.

The error bubbles through the event processing loop, breaking it and
hanging the application.

Instead, there is now a .exception(e) method on XMLStream which may
be overridden or reassigned that will receive all unhandled exceptions
(read: not XMPPError) from event and stream handlers.

sleekxmpp/stanza/rootstanza.py

@@ -64,8 +64,7 @@ class RootStanza(StanzaBase):
             # log the error
             log.exception('Error handling {%s}%s stanza' %
                           (self.namespace, self.name))
-            # Finally raise the exception, so it can be handled (or not)
-            # at a higher level by using sys.excepthook.
-            raise e
+            # Finally raise the exception to a global exception handler
+            self.stream.exception(e)
 
 register_stanza_plugin(RootStanza, Error)