Rust SDK: prefer using interfaces when they exist

[bmarty]

Draft, WIP.

The idea is to use the interfaces declared in the FFI layer as much as possible.

Sometimes the object has to be cast to be able to use FFI API. Also the FFI layer does not return systematically interface but sometimes the implementation type.

Adding useAny since the interface does not extend Disposable. Ideally it could be the case, but not a blocker, since we have the handy Disposable.destroy(...) to help (could be renamed to use but I prefer to have a different name for clarity).

I think I have use all the possible interface and at all places, but I may have missed some.

This work will help to unit test our implementation, but allowing to inject our own test implementation of the interfaces.

[github-actions]

📱 Scan the QR code below to install the build (arm64 only) for this PR.

If you can't scan the QR code you can install the build via this link: https://i.diawi.com/zidDpZ

[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Comparison is base (f80ec8a) 63.40% compared to head (234dd19) 63.40%.

Additional details and impacted files

@@           Coverage Diff            @@
##           develop    #1829   +/-   ##
========================================
  Coverage    63.40%   63.40%           
========================================
  Files         1293     1293           
  Lines        33628    33628           
  Branches      6982     6982           
========================================
  Hits         21322    21322           
  Misses        9117     9117           
  Partials      3189     3189           

☔ View full report in Codecov by Sentry.
📢 Have feedback on the report? Share it here.

[sonarqubecloud]

Kudos, SonarCloud Quality Gate passed!   

0 Bugs
0 Vulnerabilities
0 Security Hotspots
0 Code Smells

No Coverage information
No Duplication information

[jmartinesp]

This work will help to unit test our implementation, but allowing to inject our own test implementation of the interfaces.

Take into account that some of the Rust binding interfaces return or use concrete FFI class implementations as parameters, not the interfaces, so even if we could create fakes of them we'd still need to create fakes of those objects. The good news is, a couple of weeks ago a PR was merged in uniffi about making the classes open so we can fake those too as long as we don't pass them to actual Rust objects. Bad news is, I think we haven't updated to a version with that change in the Rust SDK yet.

[bmarty]

Take into account that some of the Rust binding interfaces return or use concrete FFI class implementations as parameters, not the interfaces

Yes you're right, my plan is to list all those cases (some of them are TODOs in my PR) and share it with the Rust team.

For the parameter, I think the API could work with ids. For instance if the parameter is of type Room, it could be changed to RoomInterface, but it's probably better to just pass the roomId: String.

[jmartinesp]

Honestly, before changing the API I'd just wait for the result of the PR I mentioned above to reach the Rust SDK so we don't end up changing any APIs we don't really need to. Fetching stuff from the Rust SDK with ids may not be free of side-effects, since we also need to take into account their lifetime in our code and if the backing Rust object should be kept alive, or if the object auto-starts some logic by instantiating it.

[bmarty]

the PR I mentioned above

Sorry I do not see this PR, which one is it?

[jmartinesp]

It's this one. I submitted it some time ago, along with another version that used interfaces instead and the uniffi team preferred this version with open classes, as it was easier to implement and maintain.

So with this we could just create fakes by extending the classes, and we wouldn't need to change to using identifiers and fetching new instances.

[bmarty]

Will revisit this using the open modifier added to all the Uniffi classes.