Are there any public Kotlin extensions for the Gra...

# gradle

[Eric]

Are there any public Kotlin extensions for the Gradle API? I find myself writing things like this when writing a plugin:

inline fun <reified T : Any> PluginManager.apply() = apply(T::class.java)
inline fun <reified T : Plugin<*>> PluginContainer.getPlugin(): T = getPlugin(T::class.java)
inline fun <reified T : Task> TaskContainer.withType(): TaskCollection<T> = withType(T::class.java)
inline fun <reified T : Any> ExtensionContainer.findByType(): T? = findByType(T::class.java)
inline fun <reified T : Any> ExtensionContainer.configure(action: Action<T>) = configure(T::class.java, action)

Searching is difficult because because I just get hits on “how to write plugins” etc.

Then I can write more “Kotlin-esque” code like this:

plugin.pluginManager.apply<DetektPlugin>()
        plugin.extensions.configure<DetektExtension> { detekt ->
            // ...
        }
        val detekt = target.tasks.withType<Detekt>().first()

[Sam]

Have you added the kotlin-dsl plugin to your plugin project?

[Sam]

https://plugins.gradle.org/plugin/org.gradle.kotlin.kotlin-dsl

[Sam]

That should let your plugin source code access all the regular Kotlin extensions that are accessible from build.gradle.kts scripts

[Sam]

Couldn't find many docs, but here's a small mention of it: https://docs.gradle.org/7.4/userguide/kotlin_dsl.html#sec:kotlin-dsl_plugin

[Sam]

The key point to note is that the plugin adds the gradleKotlinDsl() dependency for you, which you could also do by hand if you prefer

[Eric]

I tried adding it like this:

dependencies {
   // others...
   implementation("org.gradle.kotlin:gradle-kotlin-dsl-plugins:2.2.0")
}

But I don’t see ext functions like those in the imported jar.

[Vampire]

Because that was not what Sam said

[Sam]

You should either add

dependencies {
    implementation(gradleKotlinDsl())
}

or

plugins {
    `kotlin-dsl`
}

[Sam]

There's no need to specify a version number in either case, since the version is set automatically according to the version of Gradle

[Vampire]

If you want to know the difference, the kotlin-dsl plugin does more than just adding that dependency.
kotlin-dsl applies java-gradle-plugin, kotlin-dsl.base, and kotlin-dsl.precompiled-script-plugins plugins
kotlin-dsl.base plugin applies embedded-kotlin, adds gradleKotlinDsl() to the dependencies of compileOnly and testImplementation configurations, and configures the Kotlin DSL compiler plugins for example for proper SAM conversion for Action and similar.

So if you are just after having the Gradle Kotlin DSL classes in your dependencies, you can use gradleKotlinDsl() 🙂

[Eric]

I think I want all of that, actually.

[Eric]

Ok, cool. Thanks. Able to remove my custom ext functions now. 👍

[Sam]

Sorry if my link to plugins.gradle.org was confusing, I realise now that the code examples there don't really match either of the solutions that I actually recommended

[Eric]

I seem have lost part of the std lib, though?

inline fun <reified T : Any> KClass<T>.simpleClassName() = java.simpleName.replaceFirstChar { it.lowercase() }

It can’t resolve replaceFirstChar now.

[Sam]

The kotlin-dsl plugin will make sure you're using the version of Kotlin that corresponds to the version embedded in your Gradle version. It's possible that's an older version than what you were using before.

[Sam]

I think replaceFirstChar was added in 1.5

[Eric]

yeah, and I think this is still using 1.5. Maybe IntelliJ is confused. I’ll restart it.

[eskatos]

Gradle 7.x uses Kotlin language/api targets 1.4 for backwards compatibility. We can only change that on a major version. In Gradle 8.0 we’ll move to the latest.