Has anyone been able to use `run {}` (`JavaExec` plug-in) in Gradle but in Kotlin? It can’t work out...

# build-tools

[cedric]

Has anyone been able to use run {} (JavaExec plug-in) in Gradle but in Kotlin? It can’t work out of the box since run is part of the standard library, but even importing it and renaming it to _run still won’t let me use Gradle’s run symbol…

[serebit]

tasks.withType<JavaExec> {  }

[cedric]

@serebit I tried that already but no luck:

tasks.withType<JavaExec> {
    main = "com.beust.perry.MainKt"
    args("server", "config.yml")
}

$ ./gradlew run
* What went wrong:
Execution failed for task ':run'.
> No main class specified and classpath is not an executable jar.

[serebit]

Configure using application { }

[cedric]

@serebit That did it, thanks. Final snippet:

application {
    mainClassName = "com.beust.perry.MainKt"
}

tasks.withType<JavaExec> {
    args("server", "config.yml")
}

Why does JavaExec have a main attribute then if it’s ignored? Gradle baffles me.

[gildor]

It's not the same as Groovy snippet. withType configure all JavaExec tasks, groovy above configures only run task

[cedric]

That was my understanding too, but I assume it works here because there's only one task of this type(?)

[cedric]

In converting my .gradle to .gradle.kts, I've found that sometimes foo{ } works out of the box and other times, I have to do with(foo) { }. Again, pretty baffled.

[gildor]

Yes, correct, only one task by default

[gildor]

Direct translation would be:

tasks.named<JavaExec>("run") {}

[gildor]

but also type safe accessor is generated by Gradle

[gildor]

but in this particular case there is a problem, that run task name conflicts with Kotlin run extension

There is a task about this somewhere on kotlin issue tracker

[gildor]

So you have to somehow force usage of accessor:

(tasks.run) { }

or

tasks.run.invoke { }

[gildor]

looks strange, but at least type safe

[gildor]

I have to do with(foo) { }

In which cases do you have this?