Rejoined rooms don't get shown / disappear in the app

[Jaffex]

Steps to reproduce

In my specific case, here's what I did (on my laptop via element, since element-x does not support spaces yet):

• I was already part of the element-x-ios room (by just joining it without the public matrix space)
• I left the room and joined it again via the public matrix space (in an effort to clean up my room list a bit)

Edit: As mentioned in a below comment, it seems this issue arises from leaving and rejoining a room, and might not have to do anything with them being part of a space at all.

Outcome

What did you expect?

The (re)joined rooms would get shown in element x ios

What happened instead?

The room list does not list these rooms and searching for it via the search bar also doesn't show it.

When going back to element-x-ios, the rooms I joined via this method did not show up. Notifications for those rooms come through, but when tapping the notification, the room list is shown instead of the room.

I force closed the app and opened it again, now the rooms were visible, but one by one they disappeared from the room list again, until none of the rooms I joined via the matrix space were visible anymore.

Force closing and opening the app again makes the rooms appear again, but then they disappear again over time.

I was even able to observe this behaviour in real time - and since I had my laptop open at the same time with the same room, i noticed the following:

At the same time as a different user had caught up to the most recent message (as indicated by the read markers), the room disappeared from the room list in element-x

Your phone model

iPhone 12 mini

Operating system version

iOs 16.6.1

Application version

1.2.8

Homeserver

Synapse 1.91.0

Will you send logs?

Yes

[Jaffex]

Additional context: After each force closing and reopening the app, the rooms are visible at first.

I confirmed the behavior with the read markers once more (as soon as someone reads the last message in the room, the room disappears from element-x)

Also, when I have the same room open on my laptop, any keystroke made on the laptop inside the message composer triggers the room to disappear in element-x, just like an updated read marker seems to do.

[Jaffex]

Even more context: This behavior seems to not affect rooms that I was not previously a part of. If I join a room via the matrix space that I did not leave before rejoining, I cannot observe any disappearance of the room.

I think the issue arises not because of the spaces feature but because of leaving and then rejoining a room.

[Jaffex]

Restarting the matrix server (synapse along with the sliding sync proxy) seems to have fixed this issue for me. Issue reappears if I leave and rejoin a room - up until the next server restart.

[kegsay]

What version of the sliding sync proxy are you running?

Also, thank you for such detailed commentary, this is tremendously helpful. Given restarting the server fixes this, I suspect this is a proxy issue. Your insights re leaving->rejoining along with disappearing based on read markers / typing notifs will help me write a regression test for this.

In terms of speculating what is going wrong, I am not fully sure yet. It could be that the cache isn't being updated correctly with your rejoin, and it is reverting back to leave on read markers/typing notifs, but I'm not sure yet.

[Jaffex]

What version of the sliding sync proxy are you running?

I'm running on 0.99.10

Happy to help - thanks to you for your work in making matrix awesome :)