gradle nativeBinaries fails to satisfy dependencies - kotlin

Question

So, I wanted to generate native Kotlin binary for my app. I've came up with this build.gradle.kts:
plugins {
application
kotlin("multiplatform") version "1.3.70"
}
version = "1.0.2"
group = "org.gradle.sample"
repositories {
mavenCentral()
}
kotlin {
linuxX64("native") {
binaries {
executable()
}
}
}
dependencies {
implementation(kotlin("stdlib"))
implementation("io.javalin:javalin:3.8.0")
}
The code itself is simple:
package org.gradle.sample
import io.javalin.Javalin
fun main() {
val app = Javalin.create().start(7000)
app.get("/") { ctx -> ctx.result("Hello World") }
}
Problem here is that it fails when compiling, like if the dependencies were not satisfied:
> Task :compileKotlinNative FAILED
Caching disabled for task ':compileKotlinNative' because:
Build cache is disabled
Task ':compileKotlinNative' is not up-to-date because:
Task has failed previously.
file or directory '/home/keddad/Documents/samplekotlinapi/src/commonMain/kotlin', not found
file or directory '/home/keddad/Documents/samplekotlinapi/src/commonMain/kotlin', not found
Run tool: konanc with args: -g -ea -target linux_x64 -p library -o /home/keddad/Documents/samplekotlinapi/build/classes/kotlin/native/main/basic-api.klib -Xmulti-platform -no-endorsed-libs /home/keddad/Documents/samplekotlinapi/src/nativeMain/kotlin/org/gradle/sample/Main.kt
e: /home/keddad/Documents/samplekotlinapi/src/nativeMain/kotlin/org/gradle/sample/Main.kt: (3, 8): Unresolved reference: io
e: /home/keddad/Documents/samplekotlinapi/src/nativeMain/kotlin/org/gradle/sample/Main.kt: (6, 15): Unresolved reference: Javalin
e: /home/keddad/Documents/samplekotlinapi/src/nativeMain/kotlin/org/gradle/sample/Main.kt: (7, 20): Cannot infer a type for this parameter. Please specify it explicitly.
:compileKotlinNative (Thread[Execution worker for ':',5,main]) completed. Took 0.201 secs.
FAILURE: Build failed with an exception.
Same thing worked when compiling for JVM, but for Native it breaks. What am I doing wrong?

Answer 1

Unfortunately, you will not be able to compile this code at the moment. It seems like the Javalin framework is not targeting Kotlin/Native, it publishes only for Kotlin/JVM. The only libraries published with K/N in mind will be available to use.
In fact, the problem is that Kotlin flavors are not equivalent internally. They can share pure Kotlin code via common... source sets, but one cannot take a Kotlin/JVM project and just change the target. Kotlin/Native differs from the Kotlin/JVM, both of them are not the same as the Kotlin/JS. To make them work together, an approach named Kotlin/Multiplatform is recommended, see this article.
If you are interested in adapting this code to become multiplatform, consider looking at the Ktor. It provides support of the Kotlin/Native, and you'll be able to partially share code between platforms.