E2EE should recover rapidly from HS outages

[ara4n]

Your use case

If Bob's HS is down, Alice won't be able to set up Olm sessions to Bob. As a result, her messages to Bob will unavoidably be undecryptable.

Alice's HS could track when Bob's server returns however, and send a push notif to Alice's client when that happens (assuming Alice's client supports push) to encourage Alice to flush her olm/megolm queue and so share the missing key to Bob.

At a minimum Alice's client should track the pending olm sessions that she needs to setup, and keep retrying with a sensible retry schedule in the bg.

Have you considered any alternatives?

No response

Additional context

No response

[kegsay]

MSC4081 proposes a way to fix this.

[richvdh]

closing in favour of #2154

[richvdh]

Duplicate of #2154