NotSerializableException: kotlin.UNINITIALIZED_VALUE after setting minifyEnabled true

Question

After setting minifyEnabled true in app build.gradle script I starded to receive this exception:

Caused by: java.lang.RuntimeException: Parcelable encountered IOException writing serializable object (name = some.package.SomeClass)
    at android.os.Parcel.writeSerializable(Parcel.java:1767)
    …
Caused by: java.io.NotSerializableException: kotlin.UNINITIALIZED_VALUE

Crash occurred when I try to pass class SomeClass : Parcelable to another activity.

I tried to whitelist all app classes with -keep class some.package.**.* { *; } but without succeed.

Answer 1

I stumbled upon the same issue, and the current answer is wrong: adding @delegate:Transient on the lazy will nullify the backing field on deserialization.

Since the issue is only occuring when minifyEnabled = true, that's a Proguard/R8 issue. I solved it by adding the following lines to my proguard-rules.pro:

-keep class * implements kotlin.Lazy {
    *;
}