Unable join a room I've been invited to

[omame]

Steps to reproduce

1. Accept the invitation
2. New room opens and starts loading

Outcome

What did you expect?

Room finishes loading and I join

What happened instead?

Room never stops loading

Operating system

MacOS, Android (Element and Fluffychat apps)

Browser information

Chromium version 103.0.5060.114

URL for webapp

app.element.io

Application version

Element version: 1.11.0 Olm version: 3.2.8

Homeserver

element.io

Will you send logs?

Yes

[omame]

Here's a fun turn of events.

It turns out that I did indeed join the room (currently chatting on it) but the history never loads. This, according to @timokoesters, is due to lack of support in conduit. Thing is, my client shouldn't forever attempt to retrieve it but show an error instead.

[t3chguy]

Looks like some of the required APIs are missing

2022-07-09T06:53:38.634Z E M_NOT_FOUND: Unknown or unimplemented route
M_NOT_FOUND: M_NOT_FOUND: Unknown or unimplemented route
    at w (https://app.element.io/bundles/3021093bbd74213f659a/vendors~init.js:2:875615)
    at https://app.element.io/bundles/3021093bbd74213f659a/vendors~init.js:2:875018
    at Object.callback (https://app.element.io/bundles/3021093bbd74213f659a/vendors~init.js:2:874581)
    at https://app.element.io/bundles/3021093bbd74213f659a/vendors~init.js:2:11897
    at i.onreadystatechange (https://app.element.io/bundles/3021093bbd74213f659a/vendors~init.js:2:11921)

Element doesn't claim or want to support partial HS implementations, support there is best-effort, closing in favour of #22346 to handle codified minimum requirements

[timokoesters]

@t3chguy In this case, Element was talking to a normal Synapse, that fulfills all requirements, but that Synapse was federating with a Conduit.

I think an appropriate solution would be for Element to stop requesting history if it still errors after multiple tries. Maybe additionally Synapse should do exponential backoff on /backfill.

[omame]

If anything, throwing an error to the user rather than spinning forever would be an UX improvement.

[t3chguy]

@omame the issue says "Unable to join" - but @timokoesters is talking about history backfill. Which happened? Were you able to join or not?

[omame]

I did.

[t3chguy]

@omame please update the issue title to match the problem you are experiencing.

[omame]

I think we can close this. It happened 2 months ago today and I never experienced the issue again ever since. This because I never joined another room federated with Conduit.

So the problem, as @timokoesters pointed out, it's in the way Element and Conduit talk to each other.

As for my problem, I consider it to be expected behaviour based on the above. Thus, I'm closing this but feel free to reference it in a more generic issue to address the problem.

[t3chguy]

it's in the way Element and Conduit talk to each other.

Element wasn't talking to Conduit, the federation happens between servers.