Hello, why it isn't possible to use the multiplat...

# multiplatform

[Azur Haljeta]

Hello,

why it isn't possible to use the multiplatform plugin with apply (plugin = ...) but it is within the plugins { } block?

[Azur Haljeta]

more details here:

https://stackoverflow.com/questions/64684565/apply-kotlin-multiplatform-plugin-via-gradle-legacy-plugin-application

[Javier]

Why is it more flexible?

[Azur Haljeta]

because you can do something like

if (something){
	apply (...)
}

[Azur Haljeta]

this is useful when you would like to link a KMM project directly into android studio, and both reference the kotlin plugin, so you must write a logic where you apply that plugin only if it isn't already applied

[Azur Haljeta]

like here: https://discuss.gradle.org/t/error-plugin-already-on-the-classpath-must-not-include-a-version/31814/3

[Azur Haljeta]

and that's why it is flexible


you can't do that when using plugins via plugins {}

at least I'm not aware of

[gildor]

This is not something multiplatform plugin related, please, check Kotlin DSL documentation
Plugins dsl is the only way to generate type safe accessors for plugins. It also recommended way to apply plugins in general, buildscript is legacy mechanism

https://docs.gradle.org/current/userguide/kotlin_dsl.html#type-safe-accessors

[louiscad]

You can use apply false in the plugins DSL and call apply conditionally if you really need it that way.

[Azur Haljeta]

what's wrong with this script, such a simple example doesn't work

[Azur Haljeta]

is this also related to the Kotlin DSL

[louiscad]

Well, look at the official examples in the docs, where they also apply the right android plugin

[gildor]

I think error message is pretty explanatory

[louiscad]

Yep, there's a link to the doc in that error message @Azur Haljeta

[gildor]

Mpp plugin complaining that you didn't configure target platform

[louiscad]

@gildor If you look at the applied plugins, you can see the culprit I think 😉

[Javier]

@Azur Haljeta you need you add the android library plugin too and setup the android config like a normal library outside of kotlin, and add android() and its sourcesets inside kotlin

[Azur Haljeta]

ok ok thanks, the error message is somewhat misleading but still reasonable

[Azur Haljeta]

but how about this?

what's wrong with this one

[Azur Haljeta]

I'm intentionally pasting whole screenshots so that the script as well as the error logs are shown in a coherent form

[louiscad]

We already told you why this one doesn't work, plus I think it's not at the right place

[louiscad]

You can use the KMM plugin to make a "playground" project and see how the working config from the template is done. See the getting started docs here: https://kotlinlang.org/docs/mobile/getting-started.html

[Azur Haljeta]

@louiscad I've already done that and all is fine, but I need to tweak the configuration since it's a multi-module project and not beginner stuff.

Because of that, I need to demystify how the plugin works and why it doesn't work in Kotlin DSL with the apply notation.

I already have read most of the docs and that's why I'm asking the community since my issue is specific, and I don't think that routing back to the very beginner guides will help.

[louiscad]

apply alone will NEVER work with Kotlin DSL, it only works with dynamic Groovy

[Javier]

I have a multimodule project with dozens of multiplatform modules and I only use plugins block 🤷‍♂️

[louiscad]

Same

[Azur Haljeta]

apply alone will NEVER work with Kotlin DSL, it only works with dynamic Groovy

That's what I was missing the whole time. Thank you all!

[Javier]

I think the problem you have is a design error in your build logic and you are trying to solve it in the wrong way but I am not a Gradle expert

[louiscad]

@Azur Haljeta I think you're confusing the root "project" with the sub-projects/modules. In your last screenshot, you were adding config in the root project that should target subprojects

[louiscad]

Most plugins are not designed to be applied to the root project and propagate to child modules. At least, that's the case for the Kotlin multiplatform and Android plugins.

[Azur Haljeta]

the screenshots are just tiny hello-world projects for gradle, not related to anything specific

what I really need to do is decouple the KMM project (which includes an android app module) into two projects for two repositories, one being pure KMM and the other one is an android app which links to the KMM via settings.gradle

and that setup works when using groovy gradle but not for kotlin DSL

[louiscad]

I'm not sure I follow everything, but I can tell you that Kotlin can work like Groovy if you also use the plugins DSL + apply false in it.
Example:

plugins {
    kotlin("multiplatform") apply false // Applied conditionally later
}

[Azur Haljeta]

that's very useful, thanks @louiscad