Rooms incorrectly marked as unread

[Sorunome]

Description

Rooms which only had a whole ton of m.room.member changes are incorrectly marked as unread. It mostly happens with discord linked rooms as the discord appservice tends to generate quite a few m.room.member events.

Steps to reproduce

• Join a room with little activity
• wait for tons of m.room.member changes
• room will be marked as unread upon starting riot

Room should not be unread

Logs being sent: yes/no

Version information

Pretty much all versions since a very long time, currently on 1.3.2 desktop.

• Platform: web (in-browser) or desktop?

For the web app:

• Browser: Waterfox 56.2.12
• OS: Arch Linux
• URL: https://ponies.im/_matrix/client/develop/ and others

For the desktop app:

• OS: Arch Linux
• Version: 1.3.2

[aaronraimist]

Related: #8513 element-hq/element-meta#1088

[matejdro]

Also happens on Android client 0.9.10

[matejdro]

I did some digging and I think I found root cause of the issue:

Riot gets its unread status by Getting short list of last events and attempts to find last read message. However, this list of events is very short and if it gets filled by status messages, riot will never find any read messages there and always mark the list as read.

I am not sure what would be the best way to fix this though.

[andybalaam]

I saw this problem again this morning. Up until recently, this problem has been masked by much worse unread problems that have hopefully now been fixed by the work on stuck notifications #24392.

[leonardehrenfried]

After this issue had mostly disappeared, I'm seeing this again starting yesterday. I've submitted debug logs.

It's both the case on develop.element.io and app.element.io.

[andybalaam]

After this issue had mostly disappeared, I'm seeing this again starting yesterday. I've submitted debug logs.

It's both the case on develop.element.io and app.element.io.

Hmm - the only change we made in this area was https://github.com/matrix-org/matrix-js-sdk/pull/3706/files which we really tried to think through and make sure it didn't cause the problem. Discussion here: matrix-org/matrix-js-sdk#3684

@leonardehrenfried if you were able to provide a consistent way to reproduce the problem that would be incredibly helpful. Then we could create a test case in #25449 that would make sure we squashed the bug for good.

[leonardehrenfried]

Thanks for the response. I'm aware that this is mostly a shrug report and as an open source developer myself I know that there isn't much you can do with that.

I will keep my eyes open if I spot a pattern - so far I don't.

Does it help when I keep sending debug reports whenever it happens, which it did a moment ago?

[andybalaam]

Thank you @leonardehrenfried for your understanding. Thank you for sending reports, but we've got plenty and they mostly don't tell us what we need to know (probably because of a lack of the right logging...), so there's not much value in sending more. We are actively working on this and expect to improve it over the next few weeks.