Missing classes when minifying with R8

[hristogochev]

Attempting to obfuscate and shrink any app that uses the kotlinx.datetime library (which depends on this library) results in the following errors caused by the proguard rules of this library:

> Task :app:minifyReleaseWithR8 FAILED
AGPBI: {"kind":"error","text":"Missing class kotlinx.serialization.KSerializer (referenced from: kotlinx.datetime.serializers.InstantIso8601Serializer)\nMissing class kotlinx.serialization.Serializable (referenced from: kotlinx.datetime.Instant)","sources":[{}],"tool":"R8"}

To Reproduce

1. Create a new Android app.
2. Add the following dependency: implementation("org.jetbrains.kotlinx:kotlinx-datetime:0.4.0").
3. Create a new class which includes a field that is of type "Instant" and use it somewhere.
4. Attempt to obfuscate and shrink the app in release.

Environment

• Kotlin version: 1.9.0
• Library version: 1.5.0
• Kotlin platforms: Android JVM
• Gradle version: 8.1.0

[MarcelReiter]

Isn't this an issue of kotlinx.datetime rather than kotlinx.serialization?

[hristogochev]

I was wondering if I should open it there instead of here, but ultimately decided to post it here because it seems classes annotated with Serializable get obfuscated when they should not. If a team member thinks It's more appropriate for me to open it at kotlinx.datetime they can close this issue and I will open it in the appropriate repository.

[sandwwraith]

Given the line referenced from: kotlinx.datetime.serializers.InstantIso8601Serialize I guess it is kotlinx.datetime classes that got incorrectly obfuscated rather than kotlinx.serialiaztion classes. kotlinx.serialization distributes own proguard rules anyway. So I'd recommend open this issue in kotlinx.datetime

[MarcelReiter]

I created an issue for this in the kotlinx.datetime github:
Kotlin/kotlinx-datetime#297

It includes a minimal reproducible github project

[hristogochev]

Thank you!