This is great, thanks for working on this!
What happens for people who already have more than one session and we upgrade them? Can we take the last session? I heard that for those with multiple sessions the first sessions might have been broken, so we don't want them end up in a place where there would be one that worked but it's outside of reach.

Good point, I'm not sure what the best solution is here. When encountering multiple sessions, we could:

1. Log them all out. User would see a blank session picker screen with just the login button
2. Use the last one (not sure it's possible to know which is the last one)
3. Use whichever session is first in the array of sessions

4. Log them all out but the most recent one.

What about this?

Sadly, it doesn't seem to be possible to know which session is the most recent. So I'll go with option 1.?

Don't they have ids? I'd go with the last in the list and log all the others out.

The id is a random alphanumeric string, it's not incremental.

I'd go with the last in the list and log all the others out.

Alright, going with this one.

The screen recording doesn't shown it, but only one of the sessions was kept, the other one was logged out.

Maybe it's my local setup but when I try to build this I get:

yarn run v1.22.21
$ tsc && yarn run init && vite build --config frontend/vite-app.ts --emptyOutDir && yarn run build:logout && yarn run build:iframe && yarn run build:block
frontend/iframe/viewmodels/RootViewModel.ts:219:44 - error TS2339: Property 'resolveRoomAlias' does not exist on type 'HomeServerApi'.

219         let response = await homeserverApi.resolveRoomAlias(roomIdOrAlias).response();
                                               ~~~~~~~~~~~~~~~~

frontend/iframe/views/SessionView.ts:17:39 - error TS2307: Cannot find module 'hydrogen-web/src/platform/web/ui/session/room/WorldReadableRoomView' or its corresponding type declarations.

17 import { WorldReadableRoomView } from "hydrogen-web/src/platform/web/ui/session/room/WorldReadableRoomView";
                                         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


Found 2 errors in 2 files.

Errors  Files
     1  frontend/iframe/viewmodels/RootViewModel.ts:219
     1  frontend/iframe/views/SessionView.ts:17
error Command failed with exit code 2.

Mmm, that's weird. The build succeeded so must be something about your local setup indeed.

You could try:

rm -rf node_modules vendor
make

Hopefully that will fix it

Still the same problem. I just wanted to help and test but I suppose I need to leave it to others.

It's weird, it should just work, not sure what could be the culprit.

I noticed some other places where the session picker is shown (before a session exists), working on fixing those here too.

AFAICT, the session picker is now never shown. I added another screen recording that shows the login/logout flow.

I force-pushed to remove a useless wip commit that only changed whitespace.

Thanks for testing @ashfame! Merging.