Would it be possible to generate code from one source set into another via a KSP processor? Example being:

@Parcelize data class Foo(val bar: String): Parcelable

would generate something like

@EnforceImpl abstract class FooRoundTripParceling {...}

into the androidTest source set. Then I could have a different processor watching for annotations to pair the impl with a generated template. I assume generating some sort of resource file and doing a processor or gradle task that operates on the generated resources would be the only way to do something like this.

haven’t tried this idea before, let me know if you get any working solutions to this, I think your suspect is reasonable.