Room is stuck as unread if the most recent event is not visible.

[ara4n]

Steps to reproduce

1. Find a room where the most recent events are not visible (e.g. i have one here with a reaction and then an edit)
2. The room is shown as unread in EIX in the room list
3. View it
4. Go back to the room list
5. Room is still shown as unread

==> stuck unread. EW would be proud.

Outcome

What did you expect?

No stuck unread messages.

What happened instead?

Stuck unread.

Your phone model

No response

Operating system version

No response

Application version

339

Homeserver

No response

Will you send logs?

Yes

[ara4n]

Have sent a video on the rageshake.

[ara4n]

p.s. i only started seeing these in the last few days, so it may be a recent regression.

[ara4n]

@pixlwave says this is because started sending read receipts when we thought the user read a message, to match EAX (rather than as soon as the room is opened). so we need to be smarter about when to send them.

[bnjbvr]

matrix-org/matrix-rust-sdk#3119 should help with this, as it provides a method to mark a room as read (that sends a read receipt to the latest event, be it visible or not in the timeline). Let's see how it goes after the apps update the SDK.

[Velin92]

Fixed in the latest nighty

[manuroe]

Reopened because there is still a case where we have the bug. If the last event is a threaded message, the room stays unread. See the last rageshake.

[bnjbvr]

@manuroe The rageshake doesn't include any compute_unread_counts log lines, which is weird because it says it should (matrix_sdk_base::read_receipts=trace), so I can't investigate the failure further, unfortunately.

[bnjbvr]

The latest rageshake from @manuroe (thanks!) shows it's the issue solved by MSC4102. in https://rageshakes.element.io/api/listing/2024-02-16/140348-MQXGNP3J/logs-0001.log.gz :

2024-02-16T13:59:28.720777Z TRACE matrix_sdk_ui::timeline: sending receipt | crates/matrix-sdk-ui/src/timeline/mod.rs:721 | spans: mark_as_read{receipt_type="m.read" room_id="!mQphBNsunwlFWImZCg:matrix.org"} > send_single_receipt{receipt_type="m.read" thread=Unthreaded event_id="$yFQnSiMXamdyhLHPocwFWzrIWfIFocEM6iTdzL8iNKA" room_id="!mQphBNsunwlFWImZCg:matrix.org"}

We're sending an unthreaded read receipt for $yFQnSiMXamdyhLHPocwFWzrIWfIFocEM6iTdzL8iNKA.

The next sync returns:

2024-02-16T13:59:31.176781Z [...]
"$yFQnSiMXamdyhLHPocwFWzrIWfIFocEM6iTdzL8iNKA":{"m.read":{"@manu:matrix.org":{"ts":1707322244119,"thread_id":"$iYu51tMDt1g35qqgLPc5fs1jLDQYfNPdiucWoHIWjaM"}}}}}

So the unthreaded receipt is not forwarded, and we get the threaded receipt instead, which EX ignores, resulting in the stuck unread.

[anoadragon453]

A fix for this has merged into Synapse and is expected to be included in the v1.102.0 release. v1.102.0rc1, which includes the fix, has been deployed to matrix.org as of yesterday.

[manuroe]

We should be good on this now