does this work? I've never seen it before now

class MyPlugin : Plugin<Any> {
    override fun apply(target: Any) {
        when (target) {
            is Settings -> applyToSettings(target)
            is Project -> applyToProject(target)
            else ->
                throw IllegalArgumentException(
                    "MyPlugin can only be applied to Settings or Project, not ${target::class.simpleName}"
                )
        }
    }

we have a java version of that for the CCUD https://github.com/gradle/common-custom-user-data-gradle-plugin/blob/main/src/main/java/com/gradle/CommonCustomUserDataGradlePlugin.java#L28

nice!

instead of

Any

you could consider

PluginAware

, which

Project

,

Settings

and

Gradle

(for init plugins) all implement https://docs.gradle.org/current/javadoc/org/gradle/api/plugins/PluginAware.html

Yep. Another example: https://github.com/gradlex-org/jvm-dependency-conflict-resolution/blob/main/src/ma[…]cy/conflict/detection/JvmDependencyConflictDetectionPlugin.java