A modern programming language that makes developers happier.

kotlinlang

Hey, I’m trying to use *arrow optics* on Kotlin Multiplatform
I have a Multiplatform module with JVM only, I’ve added the Ksp plugin and
```kspCommonMainMetadata(libs.arrow.optics.ksp)
add("kspJvm", libs.arrow.optics.ksp)```
then I’ve added
```kotlin{ 
  sourceSets.all {
    kotlin.srcDir("build/generated/ksp/${this.name}/kotlin")
  }
}```
and I see the code generated under
• generated/ksp/jvm/jvmMain/kotlin
• generated/ksp/metadata/commonMain/kotlin
But the generated code is not resolved
I believe I’m missing something in the setup (?)

Running a `./gradlew build` I see
&gt; &gt; Task :stopwatch:players:data:kspCommonMainKotlinMetadata FAILED
&gt; e: [ksp] java.lang.NullPointerException: null cannot be cast to non-null type java.util.ArrayList&lt;com.google.devtools.ksp.symbol.KSType&gt;{ kotlin.collections.TypeAliasesKt.ArrayList&lt;com.google.devtools.ksp.symbol.KSType&gt; }
&gt;         at arrow.optics.plugin.internals.ProcessorKt.targetsFromOpticsAnnotation(processor.kt:51)

Hey <@UFH9XK3UJ>, this is a problem related KSP.

I’m not 100% sure what the best solution is for this issue. Is all your code inside `commonMain`? or do you have code inside `jvmMain` also?

Can you combine `kspCommonMainMetadata` with `add("kspJvm"` ? :thinking_face:

There seems to be a bug ticket related to regression from 1.6.x to 1.7.x, <https://github.com/google/ksp/issues/1125>

Thank you, Simon, all my code is in `commonMain` .
What do you mean with
&gt; Can you combine `kspCommonMainMetadata` with `add("kspJvm"` ? :thinking_face:
I thought that was the way to go, is the first time I’m trying KSP to be honest and I’ve read that `ksp()` is not suggested and will be removed

Ref: <https://kotlinlang.org/docs/ksp-multiplatform.html>

Yes, I think `ksp` specific commands are being removed. I am not sure what `kspCommonMainMetadata` does under the hood but it might be conflicting with `add("`.

Actually, on second look. You say that the generated code is not recognised but is being generated so that is not the problem.

I believe this is not correct.
```kotlin{ 
  sourceSets.all {   
kotlin.srcDir("build/generated/ksp/${this.name}/kotlin")
  }
}```
But not entirely sure how to link it for Kotlin MPP code. :thinking_face:

Maybe:

```kotlin{ 
  sourceSets.all {  
kotlin.srcDir("build/generated/ksp/jvm/jvmMain/kotlin")
     kotlin.srcDir("build/generated/ksp/metadata/commonMain/kotlin")
  }
}```

`kspCommonMainMetadata` is the “typed” alternative to `add("kspCommonMainMetadata",` 
I will try your suggestion in a sec, thank you

So I see that with both of them, I have a conflict, so I added only the JVM and seems to be fine on common code
```kotlin{ 
  sourceSets.all { 
    kotlin.srcDir("build/generated/ksp/jvm/jvmMain/kotlin")
  }
}```
About the code to be generated, it was my mistake, Arrows does generates under JVM only, the code under metadata was from Koin

But wait, with your suggestion seems like they’re generated! Probably my setup was causing the crash at build-time!