Good morning! I wanted to try out K2, but I cannot...

# k2-adopters

[Michael Böiers]

Good morning! I wanted to try out K2, but I cannot activate it in my project. When I add the code snippet from the instructions to the build.gradle.kts, I get Incorrect language version. Expected one of: '1.0', '1.1', '1.2', '1.3', '1.4', '1.5', '1.6', '1.7', '1.8', '1.9' (with plugin 1.8.20).

Any ideas?

kotlin {
    sourceSets.all {
        languageSettings {
            languageVersion = "2.0"
        }
    }
}

[semoro]

Please make sure you're using Kotlin 1.8.20 Gradle plugin

[Michael Böiers]

image.png

[Michael Böiers]

Ah, hold on …

[Michael Böiers]

Now it works! Turns out that unless I specifically say

plugins {
  id("org.jetbrains.kotlin.jvm") version "1.8.20"
}

It doesn’t work. Which opens the question: When I just say

plugins {
  id("org.jetbrains.kotlin.jvm")
}

Which version does it use?

[semoro]

Highly likely you have some other kotlin plugin block somewhere in your gradle configuration
Search for "org.jetbrains.kotlin.jvm" across the sources of your gradle files

[Michael Böiers]

You are correct. I started this project through an nx template, and it had a variable kotlinJvmVersion defined as 1.8.0. That tricked me into thinking it was a JVM language version, which of course would also not be exactly right. Maybe it’s because I have to work with Java 1.8 in client projects a lot …

[semoro]

Ah! It happens sometimes, especially when working with templates
Great to know that you found it 🙂