I have in my convention plugin for KotlinNative ad...

# compose-ios

[Joel Denke]

I have in my convention plugin for KotlinNative added freeCompiler argguments like this, see 🧵 for code.
But in my iosMain code + on clean builds I still get warnings:
This declaration needs opt-in. Its usage must be marked with '@kotlinx.cinterop.ExperimentalForeignApi' or '@OptIn(kotlinx.cinterop.ExperimentalForeignApi::class)'

How do I remove these things? Sometimes work adding them into all sourceSets, but then it complains the optins cannot be resolved in some modules not using it instead ...

[Joel Denke]

Configuration for KotlinNativeTarget.kt

Configuration for KotlinNativeTarget.kt

[Chanjung Kim]

That should fix the warning you encountered, are you putting that part before using the kotlin { iosArm64() } block?

[Joel Denke]

After having this:

fun Project.configureKotlinMultiplatform() {
    kotlinMultiplatform {
        applyDefaultHierarchyTemplate()

        androidTarget()

        iosX64()
        iosArm64()
        iosSimulatorArm64()

        targets.withType<KotlinNativeTarget>().configureEach {
            compilations.configureEach {
                compilerOptions.configure {
                    freeCompilerArgs.addAll(
                        "-opt-in=kotlinx.cinterop.ExperimentalForeignApi",
                        "-opt-in=kotlinx.cinterop.BetaInteropApi"
                    )
                }
            }
        }

        targets.configureEach {
            sourceSets.all {
                languageSettings.optIn("kotlin.ExperimentalUnsignedTypes")
            }
            configureFreeCompilerArgsArguments(
                "-Xexpect-actual-classes"
            )
        }

        configureKotlin()
    }
}

Its in a convention plugin if impacting anything.

[Joel Denke]

I can compile, but my code in iosMain always red highlighted and clean compile gives warnings all the time, very annoying as the code is correct and this setup as well as I know of. Not sure if a bug in which order using plugin aware Gradle things? Maybe need to add this earlier somehow?

[Chanjung Kim]

-opt-in should work, but if the compiler still emits the warning, try optIn.addAll instead of freeCompilerArgs.addAll. Mine is like the following:

kotlin {
  iosX64()
  iosArm64()
  iosSimulatorArm64()
}

// In a plugin:
targets.forEach { target ->
  if (target is KotlinNativeTarget) {
    target.compilations.getByName("main") { compilation ->
      compilation.compilerOptions.configure {
        optIn.add("kotlinx.cinterop.ExperimentalForeignApi")
      }
    }
  }
}

[Joel Denke]

@Chanjung Kim Thanks! 🙂 Whats the reason behind using target.compilations.getByName("main")? Why not like compilations.configureEach {?

[Joel Denke]

Also can add it works for all other targets not being iOS 😛 So its only KotlinNativeTarget problematic.

[Chanjung Kim]

> Whats the reason behind using target.compilations.getByName("main")?
Other compilations are something like test, so in my case configuring the main compilation was sufficient. I don't think compilation.configureAll would make a difference. The above code works for targets like linuxX64 or mingwX64, because they are also instances of KotlinNativeTarget. I just omitted them for brevity. You can actually do like the following as well:

arrayOf(
  iosX64(),
  iosArm64(),
  iosSimulatorArm64(),
  mingwX64(),
  linuxX64(),
).forEach { target ->
  target.compilations.configureAll { ... }
}

[Joel Denke]

Ah I see 🙂 I will test this and see if it works for my case, I tried before find something similar but had some issues 🙂
I would think maybe it dependant of order of convention plugins vs Jetbrains plugins as well.

[Joel Denke]

Btw in same topic, do you know whats difference using this vs:

targets.configureEach {
            sourceSets.all {
                languageSettings.optIn("kotlin.ExperimentalUnsignedTypes")
            }

[Joel Denke]

@Chanjung Kim Sorry to say your config didnt help, same issue. Any ideas? 😄

[Chanjung Kim]

How about using Project.afterEvaluate? Try setting that optIn in the gradle script directly, not in your plugin.

[Chanjung Kim]

A compilation depends on multiple source sets, and AFAIK, setting optIn in a sourceSet affects that sourceSet only, while setting optIn in a compilation affects all the source sets.

[Joel Denke]

I will not do that, will break Gradle cache and things, not recommended. I dont understand why it works on all other Kotlin multiplatform tarhets, but not KotlinnativeTarget :S

[Chanjung Kim]

ExperimentalForeignApi is available only on native targets.

[Joel Denke]

Yes, I mean why does it work using other opt ins for Android target, with same compiler setup, but not for iOS.

[Chanjung Kim]

You can inspect the actual arguments passed to konanc by passing --scan argument to gradlew. You can check whether -opt-in is actually passed or not to the compiler.

[Joel Denke]

How do I pass --scan to KMP run configs Jetbrains plugin setup itself? 😛 Especially for iOS I dont understand how to.

[Chanjung Kim]

Just run something like ./gradlew :linkDebugFrameworkIosArm64 --scan in the terminal

[Chanjung Kim]

I had the same issue, and maybe this is because you were using metadata (I assume, I don't know the exact name) sourceSets like nativeMain, which is different from real native sourceSets like iosArm64Main.

kotlin.sourceSets.configureEach {
  languageSettings.optIn("kotlinx.cinterop.ExperimentalForeignApi")
}

solved the problem.