I have a multi-module android project (with different module types: libraries, apps, and plain java). In the root gradle script, I have included the android application and android library plugins in my classpath (with an "apply:false" suffix) as I need them (e.g. they are used by ktlint and other plugins). Now, I have an app module that needs Kotlin 2.1.0, while the rest of the project needs and uses Kotlin 1.9.20. If I apply the Kotlin plugin 2.1.0 in the module's build script (in its plugins block), I get an error that the plugin cannot be resolved because it's already on the classpath with a different version (1.9.20):

Error resolving plugin [id: '.jetbrains.kotlin.android', version: '2.1.0']

> The request for this plugin could not be satisfied because the plugin is already on the classpath with a different version (1.9.20).

Is there a way to get this working (without detaching the module from the project/repository)?

I have this settings.gradle.kts in my project's root:

pluginManagement {
    repositories {
        mavenLocal()
        google()
        mavenCentral()
        gradlePluginPortal()
    }
}

dependencyResolutionManagement {
    repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
    repositories {
    mavenLocal()
    google()
    mavenCentral()
}
}

rootProject.name = "my-project"

include(":sdk")
include(":api")
include(":apps:test")
include(":shared")
// rest of the modules and script

And this build.gradle.kts (in root):

import .jlleitschuh.gradle.ktlint.KtlintExtension
import .jlleitschuh.gradle.ktlint.reporter.ReporterType

plugins {
    alias(libs.plugins.kotlin.android) apply false
    alias(libs.plugins.kotlin.jvm) apply false
    alias(libs.plugins.kotlin.serialization) apply false
    alias(libs.plugins.kotlin.parcelize) apply false
    alias(libs.plugins.android.library) apply false
    alias(libs.plugins.android.application) apply false
    alias(libs.plugins.android.dynamic.feature) apply false
    alias(libs.plugins.test.android.junit5) apply false
    alias(libs.plugins.apiChecker) apply false
    alias(libs.plugins.detekt)
    alias(libs.plugins.ktlint)
    alias(libs.plugins.jacoco)
}

apply(from = "jacoco.gradle.kts")

jacoco {
    toolVersion = libs.versions.jacoco.get()
}

detekt {
   // detekt config
}

Here is the app module's build script:

plugins {
    alias(libs.plugins.android.application)
    alias(libs.plugins.kotlin.android.v2)
    alias(libs.plugins.kotlin.serialization)
    alias(libs.plugins.kotlin.parcelize)
}

Relevant part of my version catalog:

kotlin = "1.9.20"
kotlin-v2 = "2.1.0"

[plugins]
kotlin-android = { id = ".jetbrains.kotlin.android", version.ref = "kotlin" }
kotlin-android = { id = ".jetbrains.kotlin.android", version.ref = "kotlin-v2" }

I have a multi-module android project (with different module types: libraries, apps, and plain java). In the root gradle script, I have included the android application and android library plugins in my classpath (with an "apply:false" suffix) as I need them (e.g. they are used by ktlint and other plugins). Now, I have an app module that needs Kotlin 2.1.0, while the rest of the project needs and uses Kotlin 1.9.20. If I apply the Kotlin plugin 2.1.0 in the module's build script (in its plugins block), I get an error that the plugin cannot be resolved because it's already on the classpath with a different version (1.9.20):

Error resolving plugin [id: '.jetbrains.kotlin.android', version: '2.1.0']

> The request for this plugin could not be satisfied because the plugin is already on the classpath with a different version (1.9.20).

Is there a way to get this working (without detaching the module from the project/repository)?

I have this settings.gradle.kts in my project's root:

pluginManagement {
    repositories {
        mavenLocal()
        google()
        mavenCentral()
        gradlePluginPortal()
    }
}

dependencyResolutionManagement {
    repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
    repositories {
    mavenLocal()
    google()
    mavenCentral()
}
}

rootProject.name = "my-project"

include(":sdk")
include(":api")
include(":apps:test")
include(":shared")
// rest of the modules and script

And this build.gradle.kts (in root):

import .jlleitschuh.gradle.ktlint.KtlintExtension
import .jlleitschuh.gradle.ktlint.reporter.ReporterType

plugins {
    alias(libs.plugins.kotlin.android) apply false
    alias(libs.plugins.kotlin.jvm) apply false
    alias(libs.plugins.kotlin.serialization) apply false
    alias(libs.plugins.kotlin.parcelize) apply false
    alias(libs.plugins.android.library) apply false
    alias(libs.plugins.android.application) apply false
    alias(libs.plugins.android.dynamic.feature) apply false
    alias(libs.plugins.test.android.junit5) apply false
    alias(libs.plugins.apiChecker) apply false
    alias(libs.plugins.detekt)
    alias(libs.plugins.ktlint)
    alias(libs.plugins.jacoco)
}

apply(from = "jacoco.gradle.kts")

jacoco {
    toolVersion = libs.versions.jacoco.get()
}

detekt {
   // detekt config
}

Here is the app module's build script:

plugins {
    alias(libs.plugins.android.application)
    alias(libs.plugins.kotlin.android.v2)
    alias(libs.plugins.kotlin.serialization)
    alias(libs.plugins.kotlin.parcelize)
}

Relevant part of my version catalog:

kotlin = "1.9.20"
kotlin-v2 = "2.1.0"

[plugins]
kotlin-android = { id = ".jetbrains.kotlin.android", version.ref = "kotlin" }
kotlin-android = { id = ".jetbrains.kotlin.android", version.ref = "kotlin-v2" }

• android
• kotlin
• gradle

1 Answer 1

When you apply false the Kotlin plugin for a given version in the root build.gradle.kts, you are adding the code for that version to the classpath of all the builds.

If you want to use different Kotlin plugin versions in different subprojects then you cannot use this approach as it would clash with the different Kotlin plugin version you are using. Therefore you must not apply false the Kotlin plugin in the root build.gradle.kts.

Instead, you can apply the Kotlin for the specific version needed in each subproject. I recommend doing this via convention plugins that will help you keep as much configuration in a central location as possible.