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kotlinlang

when updating Kotlin to 2.2.0, I'm getting <https://github.com/typesafegithub/github-workflows-kt/actions/runs/15907910145/job/44867649881?pr=1996|this> when building `buildSrc`:
```e: file:///home/runner/.gradle/caches/modules-2/files-2.1/org.jetbrains.kotlin/kotlin-reflect/2.2.0/4258f471b10f4fce1b1c000b59495b7413e1af9a/kotlin-reflect-2.2.0.jar!/META-INF/descriptors.jvm.kotlin_module Module was compiled with an incompatible version of Kotlin. The binary version of its metadata is 2.2.0, expected version is 2.0.0.```
Do I think correctly that we need to wait for Gradle supporting metadata of at least 2.1.0?

either you need to use "org.jetbrains.kotlin.jvm" plugin version `2.2.0` in `buildSrc` or wait for Gradle 9.0

but then I'm getting
```WARNING: Unsupported Kotlin plugin version.
The `embedded-kotlin` and `kotlin-dsl` plugins rely on features of Kotlin `2.0.21` that might work differently than in the requested version `2.2.0`.```
Does it mean that as long as I don't use any features that changed their behavior across these versions, things will work fine?

What you have there in `buildSrc` is as follows:
1. You use `kotlin("jvm") version embeddedKotlinVersion`
2. `dependencies { implementation(platform("org.jetbrains.kotlin:kotlin-bom:2.2.0"))`
It means the compiler is the one embedded in Gradle while you supply it with a much newer libraries. That is not guaranteed to work as Kotlin does not guarantee forward compatibility.

I’m afraid there are no good solutions there.

a) You could stick with kotlin-serialization that is compatible with the minimal Gradle version you want to support. Then your plugin will
b) You could shade kotlin-* libraries so your Gradle plugin uses its own variation of kotlin-* which does not interfere with the ones Gradle provides.

Frankly shading does not sound great. Having a limit on kotlin-serialization version might be ok.

<https://kotlinlang.org/docs/kotlin-evolution-principles.html>

&gt; Forward compatibility is *not guaranteed*. For example, the 2.0.x compiler is not guaranteed to read binaries produced by the 2.1.x compiler
&gt;  Preferably (but we *can’t guarantee* it), the binary format is mostly forwards compatible with the next language release

thanks! I actually moved to `kotlin("jvm") version "2.2.0"` (<https://github.com/typesafegithub/github-workflows-kt/blob/2cfe6e53f727d7de3934043719b0e55b423fe63e/buildSrc/build.gradle.kts#L5|ref>), I guess it's good enough for now