I'm getting when applying the Kotlin Multiplatform...

# gradle

[CLOVIS]

I'm getting when applying the Kotlin Multiplatform plugin as well as the Android library plugin…

Could not create an instance of type org.jetbrains.kotlin.gradle.plugin.mpp.KotlinAndroidTarget.
> Could not generate a decorated class for type KotlinAndroidTarget.
   > com/android/build/gradle/api/BaseVariant

The error message doesn't help me at all, where should I look for to fix this?

[mbonnin]

There should be more to it like causes and so on if you run with --stacktrace

[mbonnin]

Usually it's a NoSuchMethod exception because some wrong dependency was put in your classloader

[CLOVIS]

org.gradle.api.reflect.ObjectInstantiationException: Could not create an instance of type org.jetbrains.kotlin.gradle.plugin.mpp.KotlinAndroidTarget.
Caused by: org.gradle.internal.instantiation.ClassGenerationException: Could not generate a decorated class for type KotlinAndroidTarget.
Caused by: java.lang.NoClassDefFoundError: com/android/build/gradle/api/BaseVariant
Caused by: java.lang.ClassNotFoundException: com.android.build.gradle.api.BaseVariant

[CLOVIS]

It seems you're right, how can I find out why it's behaving this way?

[mbonnin]

Mmm looks more like no AGP is loaded in your classpath

[mbonnin]

Did you apply the android plugin?

[CLOVIS]

com.android.library , yes

[mbonnin]

Interesting... Maybe it's not loaded in the same classpath as your Kotlin plugin

[mbonnin]

Make sure to put them one next to the other

[mbonnin]

If you're applying AGP in the root build.gradle.kts, put KGP next

[mbonnin]

Same if your in buildSrc, or buildscript {}

[CLOVIS]

I tried Kotlin-then-AGP, and the opposite, same thing

It's a regular project, not the root project nor buildSrc, I am referring to both plugins using a version catalog though

[mbonnin]

Note that by applying, I mean "load the jar" so

plugins {
  id("com.android.application").version(foo).apply(false)
}

is also loading the jar

[mbonnin]

Apply AGP first ?

[mbonnin]

Maybe it's a simple ordering issue

[CLOVIS]

Doesn't seem to change anything

[CLOVIS]

Ah, I added the plugin with apply(false) to the root project and now it's fine

[mbonnin]

Welcome to classloader hell

[CLOVIS]

🎉