I'm looking at the new `compose stability analyze ...

# compose

[ursus]

I'm looking at the new compose stability analyze IDE plugin (https://github.com/skydoves/compose-stability-analyzer/)
and I have a question about this callsite.

on one hand it says ActiveTariff and List<Dashboard.DataUsageTile> which are both sealed classes - they cannot be determined at compile time - but CAN at runtime, right? (also, why? all the children are right there in the same module & they're data classes, I figured the compile time analysis works on AST or something like that; not speculative execution)

on the other hand the whole RegularBody is not skippable due to the 2 being unstable - why? I though they can be be stable but deferred to runtime, no? and if proven such, then the RegularBody should be skippable, no?

[shikasd]

Yeah, the plugin is just wrong here

[ursus]

How so? I thought it only surfaces the compose compiler outputs

[ursus]

or is that just bad wording?

[shikasd]

No, it copied the logic for analysis. It is /quite/ hard to use compiler outputs for this kind of real-time analysis

[ursus]

dammit thats even worse than not knowing :d

[shikasd]

The runtime stability means that these classes are from a different module, and it is stable, but we cannot prove that it won't be unstable as the module evolves (e.g. if it is a library that you upgrade). The runtime stable values just check a stable flag on the class instead of explicitly being resolved to stable.

If you are using version of Kotlin that is new enough (after 2.0, I believe), you have strong skipping enabled, and then your function is /always/ skippable. Compose just compares unstable values by reference instead of equals in that case, which is fine in 90% of cases.

[ursus]

> The runtime stability means that these classes are from a different module, and it is stable, but we cannot prove that it won't be unstable
does that mean even a data class, but from a different module will only be compared by === ?

[ursus]

or a sealed class from the same module, also only ref check? (even if the concrete child type is a data class?)


(yes im on new stuff so strong skipping is on)

[Konstantin Tskhovrebov]

I'd recommend using the official compose compiler debug report https://developer.android.com/develop/ui/compose/performance/stability/diagnose