Canonical issue for message stuck as latest message

[turt2live]

There's been more instances of this recently. See linked rageshakes.

See also:

• Private conversation: Specific message gets pushed to the bottom of the conversation despite being older #9894
• https://github.com/matrix-org/riot-web-rageshakes/issues/1564

[turt2live]

My current theory (with no evidence) is that our timeline splicing magic is splicing things in the wrong order, causing a non-live timeline in the front which happens to have a single message.

[Biep]

A double example:
https://matrix.to/#/!jIkxpZVHbomQzbUTua:matrix.org/$s_kH7e4MX8_mG4oTf1pHmladWI5BbKAeavO64iHYzdQ?via=matrix.org&via=privacytools.io&via=1312.media
and
https://matrix.to/#/!jIkxpZVHbomQzbUTua:matrix.org/$adot7JtGQkQk14XsghRUZK-jUvyD2ZKkTdXpUy_EogM?via=matrix.org&via=privacytools.io&via=1312.media

[ara4n]

I've had this ~4 times today.

[taw00]

That "Testing 1.5.15" should be right after the "Building 1.5.15 RPMs" message. Alas. :)
Sent debug logs at 15:55 Eastern US time.
Clear cache and reload "fixed" the issue. At least for now.

[Biep]

I also have a stuck "X is writing", which stays at the bottom. Very confusing. It has been there basically as long as the two messages above, so the same logs would apply.

[turt2live]

@Biep that is an entirely different problem.

[Biep]

Oh, I see. For the layman it looks the same: a message stuck at the bottom of the timeline.
Anyway - those logs would still apply.
Emptying the cache solved both problems.

[turt2live]

We're suspecting the latest resurgence of this is happening in Synapse and not in Riot. Once fixed, please leave this issue open as there's still some legitimate cases of Riot screwing it up.

[turt2live]

The Synapse team is identifying the recent cause for this (looks to be something with sync streams). Taking off our board as there's nothing for us to do as a client team yet.

[turt2live]

Latest bunch of this moved to matrix-org/synapse#7206

[Biep]

Yet - reloading the cache solves the problem.

[turt2live]

Yup, that's the recommended temporary fix.

[t3chguy]

Yet - reloading the cache solves the problem.

Yes, because synapse sends the right thing on initial syncs but misses events on regular syncs.

[ara4n]

the most recent instances of this seem to be https://github.com/vector-im/riot-web/issues/1541

[turt2live]

We appear to have this tracked on other issues, and at this point we don't need a firepit of issues anymore. We did at the time due to the huge volume of reports, but since May 4th this appears fixed enough for it to not be a concern.