Extending Gradle DSL (RepositoryHandler)

I want to create a function in the Gradle DSL, specifically in org.gradle.api.artifacts.dsl.RepositoryHandler. I’m writing the plugin in Kotlin and releasing it to the gradle plugin portal.

fun RepositoryHandler.something(something: String) {
  maven { repo ->
    repo.name = something
    repo.url = URI.create("https://something.test/$something")
    repo.credentials { creds ->
      creds.username = System.getenv("SOMETHING_USERNAME")
      creds.password = System.getenv("SOMETHING_PASSWORD")

This works for build.gradle.kts files, but not with Groovy. Is there a better to way to create it? If so, please guide me the right way! <3

This is used in build.gradle(.kts)? files:

repositories {

Hmm, let me think whether I will answer something different than in Slack, …, …, …, no, I think I just post a link to our conversation. :stuck_out_tongue: