ext in buildscript can not be recognised by Gradle Kotlin DSL

Question

In these days, I am trying to write some codes to experience the Spring reactive features and kotlin extension in Spring 5, and I also prepared a gradle Kotlin DSL build.gradle

Answer 1

It is possible to use constants defined in .kt file in .gradle.kts files.

create buildSrc folder in root folder of your project

create buildSrc/build.gradle.kts file with the following content

plugins {
    `kotlin-dsl`
}

repositories {
    mavenCentral()
}

create file buildSrc/src/main/kotlin/Constants.kt with the following content

object Constants {
    const val kotlinVersion = "1.3.70"
    const val targetSdkVersion = 28
}

Synchronize. Now you may reference created constants in various .gradle.kts files like this

...
classpath(kotlin("gradle-plugin", version = Constants.kotlinVersion))
...

...
targetSdkVersion(Constants.targetSdkVersion)
...

Answer 2

With Kotlin DSL ext has been changed to extra and it can be used under buildscript.

Eg :-

buildscript {
    // Define versions in a single place
    extra.apply{
        set("minSdkVersion", 26)
        set("targetSdkVersion", 27)
    }
}

Answer 3

There is a new possibility with Kotlin we can use:

object DependencyVersions {
    const val JETTY_VERSION = "9.4.12.v20180830"
}

dependencies{
    implementation("org.eclipse.jetty:jettyserver:${DependencyVersions.JETTY_VERSION}")
}

Here, DependencyVersions is a name I chose. You can choose another name, like "MyProjectVariables". This is a way to avoid using the extra or ext properties.

Answer 4

Global properties in kotlin-gradle-dsl:
https://stackoverflow.com/a/53594357/3557894

---

Kotlin version is embedded into kotlin-gradle-dsl.
You can use dependecies with embedded version as follows:

implementation(embeddedKotlin("stdlib-jdk7"))

classpath(embeddedKotlin("gradle-plugin"))

Answer 5

What is working for me is using ext in allprojects instead of buildscript, so in your top-level build.gradle.kts

allprojects {
  ext {
    set("supportLibraryVersion", "26.0.1")
  }
}

then you can use it in build.gradle.kts files in modules like this:

val supportLibraryVersion = ext.get("supportLibraryVersion") as String