Public bug reported:

We have seen some massive, robotic subscribes and confirmations. In rare cases a TypeError can be thrown. This occurs because in processing, the CGI script retrieves the pending entry more than once. If the initial retrieval returns None, an appropriate message is returned, but if two clients confirm the same token at the same time, both initial retrievals may succeed, but then subsequent processing locks the list and retrieves the data again. The first client to get there processes the confirmation which removes the token. Then when the list is unlocked, the second client gets None for the pending data and throws TypeError when retrieving things from None.

** Affects: mailman Importance: Undecided Status: New