Java Versions plugin doesn't support KotlinCompile

[mglazer]

What happened?

I have a project which uses Kotlin. I wish to use modern JVMs and therefore employ the Java Versions plugin. However, the current implementation of the Java Versions plugin only supports:

• Groovy
• Scala
• Java

This all makes sense since these are in the public Java API. However, right now I have to add additional configuration:

kotlin {
    jvmToolchain {
        languageVersion.set(JavaLanguageVersion.of("17"))
    }
}

Per the docs: https://kotlinlang.org/docs/gradle.html#setting-jdk-version-with-the-task-dsl

to make this work.

What did you want to happen?

I'd want the Java versions plugin to configure my Kotlin compiler. I did a bit of sleuthing, and it does seem like this is fairly non-trivial to do if you don't want to bring in the entire Kotlin dependency to get access to the UsesKotlinJavaToolchain spec:

https://github.com/JetBrains/kotlin/blob/cca2680c7f1c3e690a9f4a56f13449f20ebfaa6d/libraries/tools/kotlin-gradle-plugin-api/src/common/kotlin/org/jetbrains/kotlin/gradle/tasks/UsesKotlinJavaToolchain.kt

Otherwise I probably would have committed a fix, which would have involved taking what is probably an undesirable dependency on Kotlin in this plugin.