Compilation error with R8 8.5.xx and compose type safe navigation

[Beb3r]

When using compose navigation type safe and switching to R8 tool version 8.5.xx (8.5.10/8.5.27/8.5.35) compilation fails

Please ensure that class is marked as '@serializable' and that the serialization compiler plugin is applied.
at kotlinx.serialization.SerializationException.(SerializationException.java:49)
at kotlinx.serialization.internal.Platform_commonKt.serializerNotRegistered(Platform_common.kt:91)
at kotlinx.serialization.SerializersKt__SerializersKt.serializer(SerializersKt__Serializers.kt:278)
at kotlinx.serialization.SerializersKt.serializer(Serializers.kt:1)
at androidx.navigation.NavDestinationBuilder.(NavDestinationBuilder.kt:91)
at androidx.navigation.compose.ComposeNavigatorDestinationBuilder.(ComposeNavigatorDestinationBuilder.kt:95)

When falling back to R8 8.3.xx (8.3.37/8.3.36), compilation doesn't fail.

Environment

• Kotlin version: 2.0.0
• Kotlinx serialization: 1.6.3
• Gradle version: 8.7
• Gradle plugin version: 8.6.1
• Navigation: 2.8.0

Is there some new proguard rules to add ?

[sandwwraith]

This looks like R8 issue. Have you tried reporting this to Google's issue tracker?

[Beb3r]

Good point!
Just did
https://issuetracker.google.com/issues/371227633

[Beb3r]

Adding the @keep annotation on routes fixed the issue
(Navigation safe type relies on serialization, but since they're not referenced at runtime, R8 strips them away)

[sandwwraith]

Can it be the same issue as #2861 ? Do you use @Serializable object or only @Serializable class?