If remote user leaves room, changes device and rejoins we see update in /keys/changes is flaky

[richvdh]

https://github.com/matrix-org/synapse/pull/10745/checks?check_run_id=3524341005

[DMRobertson]

Wasn't able to reproduce this locally. I think the example in question got stuck waiting for matrix_leave_room_synced but I can't see any clues there.

It would be really helpful if we could match up request ids from sytest logs to synapse logs!

For completeness, I was trying to reproduce with this:

while docker run --rm -v /home/dmr/workspace/synapse:/src:ro -v /home/dmr/workspace/sytest/:/sytest -v /tmp/logs:/logs -e POSTGRES=1 -e WORKERS=1 -e MULTI_POSTGRES=1 matrixdotorg/sytest-synapse:testing --torture-replication 50 -s tests/41end-to-end-keys/06-device-lists.pl; do :; done

[clokep]

Also https://github.com/matrix-org/synapse/runs/3897959755

[DMRobertson]

And https://github.com/matrix-org/synapse/runs/3963086280?check_suite_focus=true

[richvdh]

and https://github.com/matrix-org/synapse/runs/4106909748?check_suite_focus=true

[DMRobertson]

and https://github.com/matrix-org/synapse/runs/4431172752?check_suite_focus=true

[richvdh]

and https://github.com/matrix-org/synapse/runs/4621032498?check_suite_focus=true

[DMRobertson]

and https://github.com/matrix-org/synapse/runs/4719905893?check_suite_focus=true

[DMRobertson]

https://github.com/matrix-org/sytest/runs/6111956286?check_suite_focus=true

[richvdh]

https://github.com/matrix-org/synapse/runs/6588295124?check_suite_focus=true