[Standards-JIG] An XMPP Race Condition most Vexing

[Chris Mullins]

Matthias Wrote:

[Chris Thinks XMPP Transactions cool]

[Keeping Presence Subscriptions in-sync across s2s]

> I think I described how this works about a year ago. 
> (Short: if you receive a presence probe, but the 
> probing sender is not subscribed, then send unsubscribed; 
> if you receive a presence stanza you are not interested 
> in, then send unsubscribe.)

We can come up with special case solutions to almost all of the problems. I can certainly code in optimistic concurrency to fix the original problem I described. No trouble. 

The trouble comes up in that we would end up with lots of special case solutions that could all be solved by XEP-Transaction. This includes areas such as presence subscriptions, all sorts of MUC and PubSub edge cases, and most B2B scenarios. 

--
Chris Mullins