Chunks of history are going missing

[ara4n]

Steps to reproduce

Fg the app. View a room. Grey spinner (eventually) goes away. most recent messages are missing and don’t return on sending messages into the room

Outcome

I can’t trust the app if it drops messages.

Your phone model

12 Pro max

Operating system version

15.1.1

Application version

1.6.11 stable

Homeserver

matrix.org

Will you send logs?

Yes

[manuroe]

I think there is an issue with temporary RoomDataSource and timeline.
If you open a permalink, the app will consider this temporary RoomDataSource and timeline as the live ones, which is wrong.

[ara4n]

i had it again (but no permalink involved this time): https:/matrix-org/element-ios-rageshakes/issues/14107

[manuroe]

I think there is an issue with temporary RoomDataSource and timeline. If you open a permalink, the app will consider this temporary RoomDataSource and timeline as the live ones, which is wrong.

I failed to reproduce the issue with permalinks but I still think the app is not displaying the live data when the bug happens.

A bit of history: the code used to have a big storyboard that represented the whole app navigation. It means the navigation was statically defined there and we were not able to stack rooms while opening different permalinks.

We changed the app navigation in 1.6.6. It is now possible to visit another room from a permalink and come back to the original room when pressing back.
In this case we are switching between live room data sources and past room data sources. I wonder if there is a bug where we get stuck on past data instead of switching back to live data.

[ara4n]

An alternative theory I was contemplating is whether messages are being received by the NSE and stored as incremental syncresponses, but then a race between the NSE and the main app means that the queued responses don't make it to the fg app. (e.g. perhaps the NSE doesn't bother storing the syncresponse if it thinks the fg app has already synced up to that point - but the fg app might not have yet?). This would then make this similarish to #5426.

[Anderas]

Whilst investigating this issue I encountered a similar looking, but probably unrelated issue where none of the remote messages appear in a room #5509. Fixing this before returning to chunks of history missing.

[spantaleev]

I can’t trust the app if it drops messages.

.. is a nice way to put it. The app has one job and it's not doing it. I'm not sure if it's one or multiple issues that are involved in this, but I was hitting this fairly frequently (multiple times per day), to the point where I said "this can't be trusted" and switched to another app.

[Anderas]

Going to add some further debug / logging tools into the app first to help with reproducing and fixing this issue.

[ismailgulek]

Latest fixes about duplicated rooms should have fixed this issue. Feel free to reopen if reproduced.