Using Kotlin reflection sealedSubClasses property in Android release build

Question

When I am trying to use the sealedSubClasses attribute of a reified class in Kotlin, it only works in my debug and not in my release build. I guess this is a problem with ProGuard, but I don't know how to fix this. I already tried keeping all classes in the module where the sealed class is, but I am having no luck with this. The sealedSubClasses property always returns an empty list.

Answer 1

Found two ways to fix this issue:

1. Add rule to your proguard-rules.pro file:

    -keep class com.example.ClassName { *; }
    -keep class com.example.ClassName$* { *; }

2. Use @Keep annotation:

    @Keep
    sealed class ClassName{
        @Keep
        object A : ClassName()
        @Keep
        object B : ClassName()
    }

This one didn't work for me:

-keep class kotlin.Metadata { *; }

Also there is a bug https://issuetracker.google.com/issues/169264693 that could be the part of your problem.

Answer 2

You can try

-keep class kotlin.Metadata { *; }

to get missing attributes from your class