chore: Remove the old Latest Event API

[Hywan]

This set of patches remove the old latest event API, since the new one is now available and working.

Finally, this set of patches also remove the new_ prefix from the new latest event API.

🎉

---

• Address [meta] Latest Event API, the missing one #4112
• Address The roomlist order jumps around (spasms) fairly wildly when syncing. element-hq/element-x-ios#4814

[codecov]

Codecov Report

❌ Patch coverage is 96.55172% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 88.50%. Comparing base (bfd8cfa) to head (3121f27).
⚠️ Report is 11 commits behind head on main.
✅ All tests successful. No failed tests found.

Files with missing lines	Patch %	Lines
crates/matrix-sdk-base/src/room/room_info.rs	83.33%	0 Missing and 1 partial ⚠️

Additional details and impacted files

@@            Coverage Diff             @@
##             main    #5624      +/-   ##
==========================================
- Coverage   88.57%   88.50%   -0.07%     
==========================================
  Files         363      362       -1     
  Lines      104838   103281    -1557     
  Branches   104838   103281    -1557     
==========================================
- Hits        92856    91407    -1449     
+ Misses       7625     7533      -92     
+ Partials     4357     4341      -16     

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[codspeed-hq]

CodSpeed Performance Report

Merging #5624 will not alter performance

_{Comparing Hywan:chore-remove-old-latest-event-api (3121f27) with main (bfd8cfa)}

Summary

✅ 50 untouched

[poljar]

This depends on #5617, right?

[Hywan]

There are orthogonal. #5617 is adding a new feature to the new Latest Event API, while this set of patches removes the old API.

The last patch of this set introduce a renaming by removing the new_ prefix. It can conflict with #5617, but it's not a big deal.

[poljar]

I think this looks fine, though it should only be merged after #5617 is merged, otherwise we're regressing in functionality.

This is also missing a changelog entry.

[Hywan]

#5617 can be merged after this PR, it won't add any regression. Right now, with the old Latest Event API was not supporting local events, so it was impossible to sort by them.

However, #3872 must be addressed so that re-decryption happens in the Event Cache. The old Latest Event API has its own re-decryption mechanism. Knowing that the new Latest Event API relies on the Event Cache, as long as the Event Cache doesn't support redecryption, we will have a regression.

So:

• Event cache: Move decryption retry in there #3872 must be addressed before merging this PR,
• feat(ui): Add the new latest_event room list sorter, and update the recency sorter #5617 can be merged at anytime.

[poljar]

#5617 can be merged after this PR, it won't add any regression. Right now, with the old Latest Event API was not supporting local events, so it was impossible to sort by them.

Ah, because #5587 added the new way to do latest events, and #5617 will only do the sorting based on the latest event.

Right, sorry for being confused.

[Hywan]

Rebased on top of main. Ready to be reviewed!

[poljar]

Nice, though I think we don't want to just drop the old values because a field got renamed.

Also, I think that this warrants a changelog entry.

[poljar]

Won't this cause some values to be lost? Don't you need a serde alias for this rename to be a no-op?

[Hywan]

Is it annoying? This feature hasn't been part of the stable version of most clients. At worse, we are just losing a “cached” data, which is easily computed. My question is: do we need to maintain compatibility in this case?

[poljar]

Didn't the EX clients switch to this API? Won't they lose the latest event in that case?

If not, feel free to leave the alias out.

[Hywan]

We agreed in our internal chat room that it's fine to drop. Only “nightly” or “beta” versions of Element X are using it, and no other clients seem to have switched to it so far. Moreover, Element X is using the LatestEventValue only recently in the UI: prior to that, it was only used by the Room List to sort items, but it was “invisible” to the app.

[Hywan]

I've resolved the merge conflict. All good now.

[poljar]

Very nice -3k. Thanks.