Hey guys. I’m trying to migrate my project from Gradle to kotlin-dsl. One issue I’m struggling with ...

# gradle

[mgrzechocinski]

Hey guys. I’m trying to migrate my project from Gradle to kotlin-dsl. One issue I’m struggling with is the usage of Gradle’s apply from: directive.

Simplifying, when my build.gradle.kts file looks like this:

plugins {
   id("kotlin-android-extensions")
}

androidExtensions {
  isExperimental = true
}

it’s works fine. However, when I try to extract plugin definition to a separated file and apply it from my `build.gradle.kts`:

apply{
  from("$rootDir/kotlin_shared.gradle.kts") //contains plugins { id("kotlin-android-extensions") }
}

androidExtensions {
  isExperimental = true
}

it fails on "Unresolved reference: androidExtensions". In Groovy version I had apply from: directive on top of my build.gradle file and it worked pretty well. Seems like kotlin’s apply { from () } doesn’t work like Gradle’s apply from: version, or am I missing sth?

[ribesg]

The second block of code you're showing no longer uses the plugins block, and you should use it for it to work better

[mkobit]

yup, the top level accessors (androidExtensions in this case) are only generated when they are applied in the plugins {} block

gradle does like a 2 phase compilation, and since the apply(from = "...") is executed and not handled in the same way, gradle doesnt know about it

so you either use plugins {} block to get accessors or need to know the type and do something like configure<org.android.AndroidExtension> {}

you can use the ./gradlew kotlinDslAccessorsReport to see what is generated by the kotlin-dal

[mgrzechocinski]

fine, I get it. Then why something like this doesn’t work either: https://github.com/mgrzechocinski/kstarter/pull/5/files

[mgrzechocinski]

what I want to achieve is to have a “common” .kts file which I can include in my Android Gradle modules

[mgrzechocinski]

in the pull request above, I get:

Script compilation errors:

  Line 7: androidExtensions {
          ^ Unresolved reference: androidExtensions

  Line 8:     isExperimental = true
              ^ Unresolved reference: isExperimental

2 errors

[mkobit]

static accessors for script plugins are not yet implemented:
https://github.com/gradle/kotlin-dsl/issues/427 / https://github.com/gradle/kotlin-dsl/issues/432

[mkobit]

for the common KTS using apply(from = "...") there is ... something (cant find it ATM) for how you can do it using buildSrc

[mkobit]

precompiled script plugins or something like that?

[mgrzechocinski]

I’m just wondering what’s the best way of sharing some common configuration code between different gradle modules. Currently, I have around 20 of them and they all need to access certain piece of shared configuration

[mkobit]

yeah i hear ya
the most common way ive seen it is using buildSrc
for example, https://github.com/gradle/kotlin-dsl/blob/master/buildSrc/build.gradle.kts#L21
and using https://github.com/gradle/kotlin-dsl/tree/master/buildSrc/src/main/kotlin/plugins

then the plugin ids can be consumed from the main build in a multi-project build

[mgrzechocinski]

yup, I already use buildSrc for my dependencies catalog which I refer to from different modules

[mgrzechocinski]

I guess my problem is Android specific as well. I have many modules which needs to access some shared piece of information like allowed build types. I can’t imagine duplicating this code across all modules. I’ll try to find some examples of open source Android multi-module projects which have migrated to kotlin-dsl

[mgrzechocinski]

thanks for help!

[gildor]

Use buildSrc for that, you can share any piece of config there as plugin or extension function

[gildor]

and check official migration guide, which also recommends to use buildSrc
https://guides.gradle.org/migrating-build-logic-from-groovy-to-kotlin/

[gildor]

In your example with androidExtensions you have a few ways to do that.
I would just applied this config every time when android-extensions plugin applied. You can easily do that in root build.gradle using plugins.withId("kotlin-android-extensions") { /* your config */ } function

[gildor]

The only problem that you don’t have type safe configuration for this, but you can use configure<YourPluginExtension> function instead

[gildor]

As I understand in your case you need this in your root project:

allprojects {
  plugins.withId("kotlin-android-extensions") {
      configure<AndroidExtensionsExtension> {
          isExperimental = true
      }
  }
}

[mgrzechocinski]

cool, thanks!

[Javier]

@gildor I am having problem with this too

[gildor]

What kind problem?

[Javier]

when I try to apply from a file

[Javier]

for example to add dependencies

[Javier]

I got this error:

[Javier]

implementation(Dependencies.kotlin)
^ Unresolved reference: implementation

[gildor]

not sure that it’s related to this thread.

[gildor]

tho quite similar reason

[Javier]

yep, I think it is the same problem really, when you use apply from + buildSrc

[gildor]

Most probably you have this problem because you use allprojects/subprojects block on a project that doesn’t apply plugin with this configuration (java/kotlin/android)

[Javier]

I am gonna try

[gildor]

so or you have to apply plugin (it’s possible in buildSrc only with precompiled script plugins) or just use dynamic syntax:

"implementation"(Dependencies.kotlin)

[gildor]

you have static accessors for configurations (and other plugin things like tasks, extensions) only if apply plugin using plugins block which available only in build.gradle.kts or in precompiled script plugins

[Javier]

if I change implementation for "implementation" the old error dissapear but I got

Configuration with name 'implementation' not found.

[gildor]

so, plugin where you apply this dependency doesn’t have implementation configuraion

[Javier]

so I need to add the plugin there?

[gildor]

see, implementation is a configuration that provided by java plugin (also implicitly used by java), check that this project where you apply this dependency have it

[gildor]

also you said that it’s apply from and buildSrc, which not clear for me, what exactly you do

[Javier]

I am trying to port build.gradle files to kts

[Javier]

https://github.com/PhilippeBoisney/ArchApp

[Javier]

in a similar project to that project

[gildor]

yes, I understand, but where do you see this error, how buildSrc related to apply (because usually no reason to use apply with any buildSrc code)

[Javier]

maybe it is not a problem of buildSrc

[Javier]

I am trying to apply this https://github.com/PhilippeBoisney/ArchApp/blob/master/android_commons.gradle

[Javier]

in the app gradle file https://github.com/PhilippeBoisney/ArchApp/blob/master/app/build.gradle

[gildor]

this plugin applies com.android.application plugin, so it sould work (and probably works in this project)

[Javier]

I am gonna try to convert directly this project

[Javier]

@gildor I just renamed the file and I wrote it in Kotlin. It is not working.

Script compilation errors:

  Line 09: android {
           ^ Unresolved reference: android

android_commons_gradle_kts.txt

[Javier]

original file: https://github.com/PhilippeBoisney/ArchApp/blob/master/android_commons.gradle

[gildor]

Yes, because you need static accessors or use dynamic plugin application syntax

[gildor]

Please, check official guide from link above (Kotlin DSL primer and Groovy to Kotlin migration guides), it explains how to migrate such logic and provides alternative to script application (which really not good choice in case of Kotlin DSL, because completely dynamic)

[Javier]

really I got it working when I don't try to use from another files

[gildor]

Yes, that what I'm saying apply scripts is dynamic feature, you cannot use almost anything in script plugin, official guide explains this and provide solutions

[gildor]

Or just share some example, it hard to follow what are exactly doing by looking on different code that actually works

[Javier]

Check this project

[Javier]

https://github.com/PhilippeBoisney/ArchApp

[Javier]

I am trying to migrate all gradle files to kts. The snippet I shared it is the android_commons.gradle