Specify kotlin version in buildSrc kotlin convention plugin - kotlin

Question

I am developing a Kotlin project with multiple subprojects as explained here
Building Kotlin Applications with libraries Sample (gradle.org)
Is it correct to specify the kotlin version as as shown below?
file: buildSrc/build.gradle.kts
dependencies {
implementation("org.jetbrains.kotlin:kotlin-gradle-plugin:<kotlin-version>")
}
Also, is it possible to move this kotlin version to a central location for declaring project-wide dependency version (for example gradle.properties or buildSrc/**/Dependencies.kt or versions catalog)? None of the approaches mentioned seems to be supported in buildSrc/build.gradle.kts.

Answer 1

There are many approaches to specify the kotlin version (or versions of any dependency) at a centralized location in a Gradle Multimodule Project.
gradle.properties
buildSrc/**/Dependency.kt
versions catalog
However, if you are defining a Kotlin Convention Plugin in buildSrc, the kotlin version is not available in buildSrc/build.gradle.kts using any of the methods mentioned above so as to pick the right kotlin-gradle-plugin.
For a workaround solution, use the following.
# file:<root>/gradle.properties
kotlinVersion=1.5.31
// file:<root>/buildSrc/build.gradle.kts
import java.io.*
import java.util.*
// read gradle.properties programmatically
val props = Properties()
FileInputStream(file("../gradle.properties")).use {
props.load(it)
}
plugins {
`kotlin-dsl`
}
repositories {
gradlePluginPortal()
}
dependencies {
val kotlinVersion = props.getProperty("kotlinVersion")
implementation("org.jetbrains.kotlin:kotlin-gradle-plugin:${kotlinVersion}")
}
In all other <root>/**/<subproject>/build.gradle.kts files access the kotlinVersion like
val kotlinVersion = project.properties["kotlinVersion"]
In settings.gradle.kts, access the kotlinVersion like
val kotlinVersion:String by settings
If anyone from the Gradle team reading this, please provide an API to access gradle.properties consistently across any of the build script files.

Answer 2

in app gradle
implementation "org.jetbrains.kotlin:kotlin-stdlib:$kotlin_version"
and project gradle
ext.kotlin_version = "1.6.0"

Answer 3

I have solved this issue by specifying kotlinVersion in gradle.properties file as below.
kotlinVersion=1.6.10
Keep gradle.properties file at outermost project level.
You can access kotlinVersion in any submodules and project as
//top level declaration
val kotlinVersion by extra(project.property("kotlinVersion"))
//usage in dependency block
"org.jetbrains.kotlin:kotlin-reflect:${kotlinVersion}"
To verify whether you are able to read it, you can specify following
println(project.property("kotlinVersion"))
This should print kotlin version as
> Configure project :
1.6.10
build.gradle.kts file
val kotlinVersion by extra(project.property("kotlinVersion"))
println("${kotlinVersion}")
group = "com.company"
version = "0.0.1-SNAPSHOT"
java.sourceCompatibility = JavaVersion.VERSION_17
repositories {
mavenCentral()
mavenLocal()
maven { url = uri("https://repo.spring.io/milestone") }
maven { url = uri("https://repo.spring.io/snapshot") }
gradlePluginPortal()
}
dependencies {
implementation("org.jetbrains.kotlin:kotlin-reflect:${kotlinVersion}")
implementation("org.jetbrains.kotlin:kotlin-stdlib-jdk8:${kotlinVersion}")
}
gradle.properties file
kotlin.code.style=official
#kotlin.parallel.tasks.in.project=true
#kapt.incremental.apt=true
org.gradle.parallel=true
org.gradle.caching=false
org.gradle.daemon=true
org.gradle.jvmargs=-Dfile.encoding=UTF-8
kotlinVersion=1.6.10
Ref:
project_properties
extra_properties