I've found the following configuration in the documentation:

dependencies {
    add("kspCommonMainMetadata", project(":test-processor"))
    add("kspJvm", project(":test-processor"))
    add("kspJvmTest", project(":test-processor"))
}

But how should I configure KSP to process classes in

src/commonTest/kotlin

?

kspCommonTestMetadata

does not seem to exist...

Hey Norbi, is it really working for you? You get your common code processed and the generated code is placed correctly? If so, would you mind to share your setup? Thanks

@Pavel Lahoda This works for me currently for my actual project setup:

dependencies {
    add("kspCommonMainMetadata", project(":test-processor"))
}

tasks.withType<KotlinCompile<*>>().all {
    if (name != "kspCommonMainKotlinMetadata") {
        dependsOn("kspCommonMainKotlinMetadata")
    }
}

kotlin.sourceSets.commonMain {
    kotlin.srcDir("build/generated/ksp/metadata/commonMain/kotlin")
}

This is exactly the nugget of information I needed to get my multi platform KSP experiment going.

I got it running as well. Found a problem, that there are actually two variants of KotlinCompile, org.jetbrains.kotlin.gradle.tasks.KotlinCompile and org.jetbrains.kotlin.gradle.dsl.KotlinCompile. The former is the correct one to use - at least that was the source of problems for me.