I'm trying to add a preprocessor task which runs w...

# gradle

[Chris B]

I'm trying to add a preprocessor task which runs whenever I compile with

task("preprocess", Exec::class) {
    group = "build"
    workingDir = File("..")
    executable = "bin/preproc"
}

tasks.named("desktopRun").dependsOn("preprocess")

but I keep getting "Task with name 'desktopRun' not found in project ':composeApp'.

[Vampire]

Some general notes:
• do not use task(...), it does not leverage task-configuation avoidance
• do not use File(...) with a relative path that resolves relative the current Gradle daemon working directory and while often this is the root project directory, this is not guaranteed and sometimes also not the case, so better use something like layout.projectDirectory.dir("..") or similar
• do not use dependsOn with a String if you can avoid it. When you create a task you get a reference to it back, use that instead if you really need dependsOn
• I wonder that tasks.named("desktopRun").dependsOn("preprocess") even compiles, tasks.named returns a TaskProvider on which you cannot call dependsOn, it should be tasks.named("desktopRun") { dependsOn(...) }, if at all
• If tasks.named("desktopRun") complains that it cannot find the task but you can execute it, then the task is not yet registered. You can instead for example do tasks.named { it == "desktopRun" }.configureEach { dependsOn(...) } which will also work for tasks registered later, but also not throw any error if no task with such a name is created at all
• Actually, any explicit dependsOn where the left-hand side is not a lifecycle task is a code smell that hints at you doing something you should not do or do wrongly, so you might re-think the approach you do. I cannot go into more detail on this one as it heavily depends on the exact situation what that task does, what it is necessary for, and so on.

[Chris B]

What should I use instead of task()?

[Vampire]

val preprocessTask = tasks.register<Exec>("preprocess") { ... } or
val preprocess by tasks.registering(Exec::class) { ... }

[Vampire]

https://docs.gradle.org/current/userguide/task_configuration_avoidance.html

[Chris B]

So preprocess is a task which needs to run before any build or compilation steps run. Only I have no idea what those steps are — I used the https://kmp.jetbrains.com/ wizard to create this multiplatform project, and it explained nothing about the configuration it created or what any of it meant. Getting the preprocessor to run before the desktopRun task is already a huge quality-of-life improvement, and I'd happily move it to where it's supposed to be if I had any idea what that was.

[Chris B]

I have no idea how to look up the dependency chain for these tasks.

[Vampire]

which needs to run before any build or compilation steps

Well, even if you get your code to work like intended, that will not the least achieve your goal.
You just configure that before desktopRun is executed preprocess needs to have been executed.
But this can well be after all compilation tasks and so on are already executed, so it does not help at all.

[Vampire]

As I said, how to do it properly I cannot say, as I don't know your build and especially not what that task is or does.
If you want that the task is executed before each and every other task possible, you can do

tasks.configureEach {
    dependsOn(preprocessTask)
}

Not that it is a good idea to do so. 😄

[Chris B]

It also doesn't work, as it creates a circular dependency on the preprocessTask

[Vampire]

Yeah, well

tasks.named { it != "preprocess" }.configureEach { dependsOn(preprocess) }

[Chris B]

That's got it.

[Chris B]

It's working now. It doesn't need to run before everything, but it's harmless if it does and it's basically instantaneous, so I'm not that bothered and without knowing the tasks which actually do the builds I can't exactly narrow it down.