Fix age field check in event echo processing

[stas-demydiuk]

Address an edge case when the server does not return the age field for some reason (as it seems like it is optional according to spec) to avoid NaN value in the event's localTimestamp field

Fixes element-hq/element-web#25875

Signed-off-by: Stanislav Demydiuk s.demydiuk@gmail.com

Checklist

• Tests written for new code (and old code if feasible)
• Linter and other CI checks pass
• Sign-off given on the changes (see CONTRIBUTING.md)

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Here's what your changelog entry will look like:

🐛 Bug Fixes

• Fix age field check in event echo processing (#3635). Fixes Threads on Conduit are not updating element-hq/element-web#25875. Contributed by @stas-demydiuk.

[germain-gg]

Looks sane to me, thank you for taking care of this!

Would you be able to reference the piece of the spec in the pull request that mentions it is optional and add a test to validate the behaviour you're covering now?

[isosphere]

Looks sane to me, thank you for taking care of this!

Would you be able to reference the piece of the spec in the pull request that mentions it is optional and add a test to validate the behaviour you're covering now?

If you check https://spec.matrix.org/v1.11/client-server-api/#room-event-format

Scroll down a little to ClientEvent, it says of the entire unsigned field:

Contains optional extra information about the event.

Everything that is unsigned is optional.

[richvdh]

Related: element-hq/synapse#8429

[dbkr]

Looks like the author hasn't come back on this one, although given it's a simple enough change we think it's valuable enough to merge. A regression test would have been great, but that's on us for not asking before.