Missing avatars or displaynames when scrolling up (Conduit)

[timokoesters]

Steps to reproduce

This requires some work to reproduce, log in on a conduit server and join a larger room, then scroll up. Maybe it requires a page refresh or cache clear as well.

The problem seems to be that Element Web relies on redundant member events to some extend, but does not send the include_redundant_members filter flag on /messages and/or /context.

Also see https://gitlab.com/famedly/conduit/-/issues/233

Outcome

User profile information missing

Operating system

Browser information

URL for webapp

staging.element.io

Application version

Homeserver

conduit.rs

Will you send logs?

No

[germain-gg]

Duplicate of #20999

[timokoesters]

@gsouquet I think this issue is different. Here the avatar shows on the newer messages but is missing on the older messages. As I said above I believe this is an issue with include_redundant_members, Element Android has this problem too: element-hq/element-android#3417

[t3chguy]

Indeed -

When processing a sequence of events (e.g. by looping on /sync or paginating /messages), it is common for blocks of events in the sequence to share a similar set of senders. Rather than responses in the sequence sending duplicate membership events for these senders to the client, the server MAY assume that clients will remember membership events they have already been sent, and choose to skip sending membership events for members whose membership has not changed. These are called ‘redundant membership events’. Clients may request that redundant membership events are always included in responses by setting include_redundant_members to true in the filter.

If Element wants to continue showing historical profiles (#3768 challenges this and has a labs option now) then it'll need to set that filter param.

[timokoesters]

Adding the filter to include redundant members should be an easy fix and has no performance consequences on synapse because it already does this by default. If this lands on nightly, please tell me so I can test it with Conduit.

[timokoesters]

Did anyone try to activate "include redundant members"? This should be a really simple change and hopefully fixes profiles on Conduit.

[timokoesters]

I've added a workaround to Conduit which just always sends all members in /messages