[jdev] presence persistence

[Mats Bengtsson]

Although not recommended, it is allowed to use presence stanzas to broadcast
custom elements (rfc3921):
"
   As described under extended namespaces (Section 2.4), a presence
   stanza MAY contain any properly-namespaced child element.
"
Each client keeps an internal state of 
the users presence state, but what happens to these states when a custom
presence is received? An example:

If I initially get

   <presence type='available' from='x' ...>
     <show>dnd</show>
   </presence>

and then later a custom presence

   <presence from='x' ...>
     <custom xmlns=.../>
   </presence>

shall the user 'x' status still be 'dnd'? 
But if I instead get

   <presence from='x' .../>

without any custom element the status is obviously 'available' and not 'dnd'.
This doesn't make any sense. One way out of this is if custom presence
included the other elements <show/> <status/> <priority/> but that seems clumsy.

We already have this situation with caps elements, but they are typically only
sent with the initial presence, and don't cause this dilemma.

Ideas?    /Mats