[muc] Call userHasLeft() *after* the leave presence was sent

Calling userHasLeft before sending the leave presence may result in
invalid state as the MUC presence lister may modify the MUCs local
state, e.g., occupantsMap, conurrently with the leave operation.

If we reset it after the leave presence was send and acknowledged,
then this can not happen as the server will not longer send any MUC
related presences to us.

Also fixes SMACK-914. In theory 52a49769f9 ("[muc] Check for
self-presence first in presence listener") alone would fix SMACK-914,
but this also fixes it indepentendly of 52a49769f9. Both commits are
sensible, so both are applied.
This commit is contained in:
Florian Schmaus 2021-10-05 20:47:35 +02:00
parent 52a49769f9
commit 105c74b22b
1 changed files with 8 additions and 5 deletions

View File

@ -789,11 +789,14 @@ public class MultiUserChat {
StanzaFilter reflectedLeavePresenceFilter = new AndFilter(reflectedLeavePresenceFilters);
// Reset occupant information first so that we are assume that we left the room even if sendStanza() would
// throw.
userHasLeft();
Presence reflectedLeavePresence = connection.createStanzaCollectorAndSend(reflectedLeavePresenceFilter, leavePresence).nextResultOrThrow();
Presence reflectedLeavePresence;
try {
reflectedLeavePresence = connection.createStanzaCollectorAndSend(reflectedLeavePresenceFilter, leavePresence).nextResultOrThrow();
} finally {
// Reset occupant information after we send the leave presence. This ensures that we only call userHasLeft()
// and reset the local MUC state after we successfully left the MUC (or if an exception occurred).
userHasLeft();
}
return reflectedLeavePresence;
}