[Standards] Threads and replies in XMPP

Hello, We've got a discussion about thread on xsf@ a couple of days ago, and I would like to bring it here. I initially thought that XEP-0461 (Message Replies) was redundant with threads, except in the case where there is no thread ID in the message a user wants to reply too. After discussion, notably with singpolyma and lovetox, it appears that we don't have the same view on this. The way I got it, we have basically 2 ways to see threads: 1. A series of replies to any message in a group chat, à la Slack (in Slack, you see the replies hidden under parent message, with something like "X replies", and when you click, a panel appear with the whole thread. 2. A side discussion explicitly started, that could be seen like a new chat window (UI example: user clicks a "start a new thread button", and start a blank window with it message, this message has a new thread ID, that will be used by people replying to it). In case 1, the parent message needs a thread ID so that thread can continue with the same ID. Problem is if parent message doesn't has a thread ID (because client doesn't support thread, or because there is no thread ID for each message), in this case a XEP-0461 "reply to" can be used, then the first reply has a new thread ID, and the thread can continue. In case 2, the explicitly started thread has a newly generated thread ID, so there is no problem. I want to support both 1 and 2. For 1, my initial reading of XEP-0201 (Best Practices for Message Threads) was that a new thread ID should be generated for each message: XEP-0201 §3.2. But after discussion, I realise that it's not requested to generate a new ID each time, and it seems that generating new thread ID for each message would be a problem for some clients (notably Cheogram which would create a thread UI for each ID). The solution would be to use "reply to" from XEP-0461, then a newly generated thread ID. I've also proposed an alternative when parent message ID could be used as thread ID, this may we can find parent message without relying on XEP-0461. For the moment, I think that I won't generate new thread ID for each message, and if I create a thread from a parent message I'll use a XEP-0461 "reply to" and generate a new thread ID, then use this thread ID for following message in this thread. However, I would like to have feedback from the wider community: - how to you handle or plan to handle threads? - Are you planning to implement case 1 (threads can be started from any message) and/or case 2 (threads are explicitly started)? - How would you handle case 1? Thanks! Best, Goffi