How to get ext.* variables into plugins block in build.gradle.kts

Question

My build file looks like this:

val nexusBaseUri: String by extra
val gradle_version: String by extra
val kotlin_version: String by extra

buildscript {
    val nexusBaseUri by extra { "https://mynexusserver/nexus" }
    val gradle_version by extra { "4.1" }
    val kotlin_version by extra { "1.1.4-3" }
    val springBoot_version by extra { "2.0.0.M3" }

    repositories {
        maven { url = uri("$nexusBaseUri/repository/public") }
        jcenter()
        maven { url = uri("http://repo.spring.io/snapshot") }
        maven { url = uri("http://repo.spring.io/milestone") }
    }
    dependencies {
        classpath("org.springframework.boot:spring-boot-gradle-plugin:$springBoot_version")
        classpath("org.jetbrains.kotlin:kotlin-gradle-plugin:$kotlin_version")
        classpath("org.jetbrains.kotlin:kotlin-allopen:$kotlin_version")
    }
}

plugins {
    application
    // vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    // the following line causes a problem
    // vvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvvv
    kotlin("jvm", kotlin_version)
}

apply {
    plugin("kotlin-spring")
    plugin("org.springframework.boot")
    plugin("io.spring.dependency-management")
}

application {
    mainClassName = "eqip.fid.FdmlInterpreterDeveloperAppKt"
}

repositories {
    maven { url = uri("$nexusBaseUri/content/groups/public") }
    jcenter()
    maven { url = uri("http://repo.spring.io/snapshot") }
    maven { url = uri("http://repo.spring.io/milestone") }
}

dependencies {
    compile(kotlin("stdlib"))
    compile("org.springframework.boot:spring-boot-starter-web")
}

tasks {
    "wrapper"(Wrapper::class) {
        gradleVersion = gradle_version
    }
}

The error I get in IntelliJ IDEA is

'val kotlin_version: String' can't be called in this context by implicit receiver. Use the explicit one if necessary

How do I fix this?

Answer 1

You can define a version inside plugins and then make this version accessible outside of the block, e.g. in the dependencies section.

plugins {
    kotlin("jvm").version("1.1.61")
}

//This is necessary to make the version accessible in other places
val kotlinVersion: String? by extra {
    buildscript.configurations["classpath"]
            .resolvedConfiguration.firstLevelModuleDependencies
            .find { it.moduleName == "kotlin-gradle-plugin" }?.moduleVersion
}

dependencies {
    compile(kotlin("stdlib", kotlinVersion))
}

for version 1.2+, you will have to replace with kotlin-gradle-plugin org.jetbrains.kotlin.jvm.gradle.plugin