[Standards] MUC Invites are no MUC PMs

Holger Weiß holger at zedat.fu-berlin.de
Tue Sep 20 10:37:34 UTC 2016

* Georg Lukas <georg at op-co.de> [2016-09-20 08:35]:
> Nothing is better than a corner case hidden inside of a corner case.


> Both prosody and ejabberd MUC implementations now mark PMs with an
> <x http://jabber.org/protocol/muc#user> element, and the respective
> carbon implementations filter away duplicates, which is good.
> Unfortunately, this logic also affects MUC invitations, as these also
> have the same <x> element. However, invitations should be delivered to
> all clients.


> Therefore, if you are implementing an XMPP server with
> carbons support, please fix your MUC PM suppression logic.


However, according to the XEP-0280 rules¹, invitations still won't be
carbon-copied unless they include a <body/>, as they are messages of
type "normal".  While at least Prosody and ejabberd do add a <body/>
right now, the current XEP-0045 examples don't (they did in the past).

Maybe XEP-0334 needs a <copy/> hint which could then be added to MUC

Apart from all that, XEP-0280 seems to say that MUC things should never
be carbon-copied:

| A <message/> is not eligible for carbons delivery if it is determined to
| have been sent by a MUC room or service, even if it would be otherwise
| eligible (this also includes private messages from MUC participants).

But I guess it was not the intention to suppress carbons delivery of MUC
invitations(?) ...


¹ http://xmpp.org/extensions/xep-0280.html#which-messages

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