[Standards] Re: Proposed XMPP Extension: Explicit Mentions

Hi, There was already discussions on that matter during Summit and I made the point that I believe we have two entirely separate issues here that IMO should also be treated entirely independent (potentially using two XEPs): (a) Markup to the body, that has the purpose to indicate that a part of the body is referring to a user or a group of users (b) Some indication that the message should have some sort of priority to a user or a group of users Here's why I believe they should be independent: - A client may decide to send both at the same time, but it doesn't need to. (a) can also happen in conversations that the referred user is not a part of and thus part (b) certainly can't apply. It is thus only logical that even if the referred user is in the same room, one should be able to send a message that does not indicate (b). - (a) is indicating to a specific instance of body, implying that in scenarios of multiple bodies (xml:lang, xhtml-im), there need to be multiple of such (a) indications, but the indication of (b) does not need to appear multiple times, as it is independent from the actual body. - The (b) indication might have some implication on servers (e.g. might receive priority for CSI when regular type=groupchat messages don't), (a) is entirely to be processed by clients. - When end-to-end encryption is used, it may be desirable to keep (b) unencrypted (so servers can process it), whereas (a) should always be encrypted when end-to-end encryption is used, as it may leak information about the message's plain text. I think this gives a good idea of why I believe those are two separate things. The XEP proposal puts them into a single thing, but does acknowledge some of the things I mention: - A mention can happen without referring to a specific part of the body, effectively turning it into a (b) only indication - A mention can happen with <noping/>, effectively turning (b) off when (a) is used Now here are problems I see with the proposed specification, directly stemming from trying to merge the two: - A mention can happen with <noping/> and without begin/end, indicating that a user/group is mentioned, which feels largely useless. - When multiple languages are used, there may be multiple <mention/> elements. What if they have conflicting <noping/> indications? On top, there's another major issue somewhat caused by merging the two: The user's home server usually does not have an understanding of group membership details, hats and so on, meaning it can't give messages priority (e.g. for CSI) based on that in the proposed protocol. So my proposal is to do two separate things for mention (which could reference each other): - A markup-only indication. This is meant to be processed by clients exclusively. I personally would prefer this being based on XEP-0394 spans, as those already have some business logic that is relevant here (spans must not cross each other, spans cannot cross block level markup) that would need to somehow be codified if it was done indpendent of XEP-0394. - For notifications in MUCs, to solve the issue that the home server does not understand details like affiliation/hats, have a new protocol that allows a sender to indicate which group they want to notify and then have the MUC translate this into XEP-0224 attention elements when reflecting the message to applicable recipients. - For priority notifications in direct chats (if messages aren't notified by default), just use XEP-0224 directly. This way we have a single standard for the receiving server/client to know that a message is important and should notify (XEP-0224). We have a single standard for markup related matters (XEP-0394). And we have a new standard to indicate to the MUC server they should notify specific recipients.