KotlinSourceSet with name 'unixMain' not found.

0. 背景

build.gradle.kt

plugins {
    kotlin("multiplatform")
}
group = "tech.eritquearcus"
version = 0.0.0.0
kotlin {
    jvm {
        compilations.all {
            kotlinOptions.jvmTarget = "1.8"
        }
        withJava()
        testRuns["test"].executionTask.configure {
            useJUnitPlatform()
        }
    }
    val hostOs = System.getProperty("os.name")
    val isMingwX64 = hostOs.startsWith("Windows")
    val nativeTarget = when {
        hostOs == "Mac OS X" -> macosX64("unix")
        hostOs == "Linux" -> linuxX64("unix")
        isMingwX64 -> mingwX64("win")
        else -> throw GradleException("Host OS is not supported in Kotlin/Native.")
    }
    sourceSets {
        val commonMain by getting {
            dependencies {
  
            }
            apply(plugin = "org.jetbrains.kotlin.plugin.serialization")
        }
        val jvmMain by getting
        val unixMain by getting
        val winMain by getting
    }
}

从代码里可以看出, 我是打算在 unixMain 和 winMain 下分别放 mac/linux 平台的实现, jvmMain 下放 java 实现.
但是在我单纯在这个项目的 src 根目录下新建 unixMain 和 winMain 后, 我发现他不会自己链接这两个文件夹(像 jvmMain 和 nativeMain 一样), 然后报错:

KotlinSourceSet with name 'unixMain' not found.

* Try:
> Run with --info or --debug option to get more log output.
> Run with --scan to get full insights.

* Exception is:
org.gradle.api.UnknownDomainObjectException: KotlinSourceSet with name 'unixMain' not found.
   at org.gradle.api.internal.DefaultNamedDomainObjectCollection.createNotFoundException(DefaultNamedDomainObjectCollection.java:504)
   at org.gradle.api.internal.DefaultNamedDomainObjectCollection.getByName(DefaultNamedDomainObjectCollection.java:333)
   at org.gradle.kotlin.dsl.NamedDomainObjectCollectionDelegateProvider.provideDelegate(NamedDomainObjectCollectionExtensions.kt:384)
   at Build_gradle$1$2.execute(build.gradle.kts:53)
   at Build_gradle$1$2.execute(build.gradle.kts:1)
    ...

1. 解决方法

用

val unixMain = maybeCreate("unixMain").apply {
    this.dependsOn(commonMain)
}
val winMain = maybeCreate("winMain").apply {
    this.dependsOn(commonMain)
}

替换

val unixMain by getting
val winMain by getting