Nullable Parameter in Fragment.arg(...) causes IllegalStateException #414
Description
When using nullable fragment args, the following works:
@ProvidesFragment(AppScope::class)
class SomeFragment @FragmentInject constructor() : Fragment() {
val viewModel: SomeViewModel by tangleViewModel()
@FragmentFactory
interface Factory {
fun create(
@TangleParam(name = "NullableArg")
nullable: SomeSerializable?
): SomeFragment
}
}
class SomeViewModel @VMInject constructor(
@TangleParam(name = "NullableArg")
nullable: SomeSerializable?
) : ViewModel() {
init {
nullable?.let { Log.d("app", "$nullable") }
}
}but if you add
val nullable by arg<SomeSerializable?>("NullableArg")you get a subclass type error (SomeSerializable? is not a subclass of Any)
and if you add
val nullable: SomeSerailizable? by arg("NullableArg")you get no type errors, but at runtime, the app crashes with
java.lang.IllegalStateException: Bundle does not contain key: NullableArg
due to nullability being used as a sentinel for illegal construction in Fragment.arg
This can be worked around by having a non-nullable data class to wrap the optional parameter, but this feels inelegant when you only need one nullable arg. Is it possible to relax the constraints so that they match those of the ViewModel?