How can I specify Kotlin compiler options for compileCommonMainKotlinMetadata task (klib generation)? I need to supress warnings about expect/actual usage. I'm setting flag -Xexpect-actual-classes to metadata target like this:

mpp.targets.getByName("metadata").compilations.forEach {
  it.compilerOptions.options.freeCompilerArgs.add("-Xexpect-actual-classes")
}

but still see warnings

Alternative could be:

tasks.named<org.jetbrains.kotlin.gradle.tasks.KotlinCompilationTask<*>>("compileCommonMainKotlinMetadata") {
    compilerOptions.freeCompilerArgs.add("...")
}

@tapchicoma thanks! Alternative is working. But why it is not applying using requested variant?

Try to avoid terminal operators such as

forEach

when iterating over Gradle-specific collections such as compilations. Instead, use

configureEach

or

all

For example like this:

kotlin {
    metadata {
        compilations.configureEach {
            compilerOptions.options.freeCompilerArgs.add("-Xexpect-actual-classes")
        }
    }
}

@Anton Lakotka [JB] Thanks! Now working both variants.