Gradle Kotlin DSL Replace Token - gradle

Question

In my code there is const val VERSION = $version.
I want to replace $version with real version string which is in my build.gradle.kts.
How can I do this?

Answer 1

Working example here.
One way is to use a template file (stored outside of src tree). Let's call it TemplateVersion.kt:
class Version() {
val version = "__VERSION";
}
and then in build.gradle.kts, as initial part of the compileKotlin task, we generate Version.kt from TemplateVersion.kt:
val sourceFile = File(rootDir.absolutePath + "/resources/TemplateVersion.kt")
val propFile = File(rootDir.absolutePath + "/gradle.properties")
val destFile = File(rootDir.absolutePath + "/src/main/kotlin/${targetPackage}/Version.kt")
tasks.register("generateVersion") {
inputs.file(sourceFile)
inputs.file(propFile)
outputs.file(destFile)
doFirst {
generateVersion()
}
}
tasks.named("compileKotlin") {
dependsOn("generateVersion")
}
fun generateVersion() {
val version: String by project
val rootDir: File by project
val inputStream: InputStream = sourceFile.inputStream()
destFile.printWriter().use { out ->
inputStream.bufferedReader().forEachLine { inputLine ->
val newLine = inputLine.replace("__VERSION", version)
out.println(newLine)
}
}
inputStream.close()
}
where gradle.properties is:
version=5.1.50
It is trivially easy to add more fields to Version.kt, such as a build-timestamp.
(Edit: This has been updated with a proper generateVersion task that will detect changes to gradle.properties. The compileKotlin task will invoke this task).