How to import KotlinMultiplatformExtension inside buildSrc module?

Question

I am developing a kotlin multiplatform project, which has a bunch of modules.

I have written an extension function which is meant to be used inside each module. The extension function extends functionality of KotlinMultiplatformExtension class. Now that code is repeated inside each module's build.gradle.kts file. So i thought it would be great to move that code to buildSrc moudle and reuse everywhere.

The problem is that inside buildSrc module KotlinMultiplatformExtension is not resolved.

My buildSrc/build.gradle.kts:

plugins {
    `kotlin-dsl`
}
repositories {
    jcenter()
}

If i right click KotlinMultiplatformExtension inside someModule/build.gradle.kts

it takes me to:

So I guessed that adding a dependency inside buildSrc/build.gradle.kts should help:

dependencies {
    implementation("org.jetbrains.kotlin:kotlin-gradle-plugin:1.4.10")
}

But adding that results with an error:

* Exception is:
java.lang.NoClassDefFoundError: com/android/build/gradle/BaseExtension
    at org.jetbrains.kotlin.gradle.plugin.AbstractAndroidProjectHandler.configureTarget(KotlinPlugin.kt:765)
    at org.jetbrains.kotlin.gradle.plugin.KotlinAndroidPlugin$Companion.applyToTarget(KotlinPlugin.kt:727)
    at org.jetbrains.kotlin.gradle.plugin.KotlinAndroidPlugin.apply(KotlinPlugin.kt:689)
    at org.jetbrains.kotlin.gradle.plugin.KotlinAndroidPlugin.apply(KotlinPlugin.kt:678)
    at org.jetbrains.kotlin.gradle.plugin.KotlinBasePluginWrapper.apply(KotlinPluginWrapper.kt:102)

Any ideas how to make KotlinMultiplatformExtension available inside buildSrc?

Answer 1

Turns out that changing

implementation("org.jetbrains.kotlin:kotlin-gradle-plugin:1.4.10")

into

compileOnly("org.jetbrains.kotlin:kotlin-gradle-plugin:1.4.10")

resolves problem with the exception (java.lang.NoClassDefFoundError: com/android/build/gradle/BaseExtension)

and makes KotlinMultiplatformExtension available inside the buildSrc's source files.

solution found here: https://github.com/gradle/gradle/issues/9209