Gradle，如何使用Kotlin库发布jdk8变体

Question

长话短说:我想为我的一个仅限kotlin的库发布一个jdk8向后兼容的变体。

这是一个长期想要的功能，我试图解决，因为相当长一段时间，但从来没有得到正确的。然而，经过多次尝试和帮助Gradle Slack，我认为我很接近，但我仍然有一个错误，我似乎无法摆脱。

我们的想法是用jdk11编译主版本(src/main和scr/jpms，后者包含简单的module-info.class)，而src/main的jdk8变体当然只用jdk8编译。

这是我当前的build.gradle.kts:

import org.jetbrains.kotlin.gradle.plugin.KotlinSourceSet
import org.jetbrains.kotlin.gradle.tasks.KotlinCompile
plugins {
kotlin("jvm") version "1.5.10"
`java-library`
`maven-publish`
}
group = "kotlin.graphics"
version = "3.3.1"
repositories {
mavenCentral()
}
dependencies {
implementation(kotlin("stdlib-jdk8"))
testImplementation("io.kotest:kotest-runner-junit5:4.4.1")
testImplementation("io.kotest:kotest-assertions-core:4.4.1")
}

val jdk8 = sourceSets.create("jdk8") {
java.srcDir("src/main/java")
kotlin.srcDir("src/main/kotlin")
}
val jdk11 = sourceSets["main"].apply {
java.srcDir("src/jpms/java")
}
java.registerFeature("jdk8") {
usingSourceSet(jdk8)
capability("group", "name", "0.1")
}
configureCompileVersion(jdk8, 8)
configureCompileVersion(jdk11, 11)
val moduleName = "$group.$name"
fun configureCompileVersion(set: SourceSet, jdkVersion: Int) {
val compiler = project.javaToolchains.compilerFor {
languageVersion.set(JavaLanguageVersion.of(jdkVersion))
}.get()
val target = if (jdkVersion == 8) "1.8" else jdkVersion.toString()
tasks {
named<KotlinCompile>(set.compileKotlinTaskName) {
kotlinOptions {
jvmTarget = target
jdkHome = compiler.metadata.installationPath.asFile.absolutePath
}
source = sourceSets.main.get().kotlin
}
named<JavaCompile>(set.compileJavaTaskName) {
targetCompatibility = target
sourceCompatibility = target
modularity.inferModulePath.set(jdkVersion >= 9)
javaCompiler.set(compiler)
source = sourceSets.main.get().allJava + set.allJava
if (jdkVersion >= 9)
options.compilerArgs = listOf("--patch-module", "$moduleName=${set.output.asPath}")
}
}
}
val SourceSet.compileKotlinTaskName: String
get() = getCompileTaskName("kotlin")
val SourceSet.kotlin: SourceDirectorySet
get() = withConvention(KotlinSourceSet::class) { kotlin }
publishing {
publications {
create<MavenPublication>("maven") {
groupId = "org.gradle.sample"
artifactId = "library"
version = "1.1"
from(components["java"])
}
}
repositories.maven {
name = "prova"
url = uri("repo")
}
}

如果我运行:assemble，生成的工件将使用jdk11正确编译。在那之前一切都如我所料。但是如果我尝试发布，我得到的却是:

任务:compileJdk8Kotlin FAILED5个可执行的任务:1个已执行，4个最新e:模块java。在模块图

中找不到基

由于某些原因，看起来Gradle试图使用jpms编译jdk8变体，尽管它应该被自动禁用。我尝试手动设置它的开启和关闭:

modularity.inferModulePath.set(jdkVersion >= 9)

但它也不工作。

项目在这里

安装7.1.1 Gradle

Answer 1

我想我明白了

// these two are simple helpers
val SourceSet.compileKotlinTaskName: String
get() = getCompileTaskName("kotlin")
val SourceSet.kotlin: SourceDirectorySet
get() = project.extensions.getByType<KotlinJvmProjectExtension>().sourceSets.getByName(name).kotlin
// pick the `main` sourceSet and use it for jdk11
val jdk11 = sourceSets.main.get()
// now we clone `main` into `jdk8`, with the only difference being the exclusion 
// of `module-info.class`. We need to call `::create` to avoid getting the 
// reference to the same sourceSet.
val jdk8 = sourceSets.create("jdk8") {
// this is superfluous, adding not-existing folders is harmless, but it's 
// rather confusing when you need to debug two sourceSet java/kotlin
java.setSrcDirs(emptySet<File>())
kotlin.setSrcDirs(emptySet<File>())
// assign the very same source directories
java.setSrcDirs(jdk11.java.srcDirs)
kotlin.setSrcDirs(jdk11.kotlin.srcDirs)
// exclude the file from both, since kotlin includes always the java sources
java.setExcludes(listOf("module-info.java"))
kotlin.setExcludes(listOf("module-info.java"))
}
// this will create the `jdk8` variant using the given sourceSet at the given
// capabilities
java.registerFeature("jdk8") {
usingSourceSet(jdk8)
// I experienced `version` to be `null` if it's declared in the 
// build.gradle.kts, then I moved it into `settings.gradle.kts to fix this
capability(group.toString(), name, version.toString())
}
// set everything for each variant, jdk11 is the default/main one
configureCompileVersion(jdk8, 8)
configureCompileVersion(jdk11, 11)
val moduleName = "$group.$name"
fun configureCompileVersion(set: SourceSet, jdkVersion: Int) {
tasks {
val target = if (jdkVersion == 8) "1.8" else jdkVersion.toString()
// we do need the task name because we have compileKotlin and
// jdk8CompileKotlin and we want to set stuff accordingly
named<KotlinCompile>(set.compileKotlinTaskName) {
targetCompatibility = target
sourceCompatibility = target
kotlinOptions {
// jdkHome is deprecated in 1.5.30
jvmTarget = target
// this is outside the variant scope
freeCompilerArgs += listOf("-Xinline-classes", "-Xopt-in=kotlin.RequiresOptIn")
}
source = sourceSets.main.get().kotlin
}
named<JavaCompile>(set.compileJavaTaskName) {
targetCompatibility = target
sourceCompatibility = target
// this is supposed to be set automatically, well with a jdk8 variant
// you need to set it up explicitly
modularity.inferModulePath.set(jdkVersion >= 9)
javaCompiler.set(project.javaToolchains.compilerFor {
languageVersion.set(JavaLanguageVersion.of(jdkVersion))
}.get())
source = set.allJava
if (jdkVersion >= 9)
options.compilerArgs = listOf("--patch-module", "$moduleName=${set.output.asPath}")
}
withType<Test> { useJUnitPlatform() }
}
}
// We also want to automatically set all the jdk11 dependencies to jdk8 as well
configurations {
named("jdk8Implementation") {
extendsFrom(implementation.get())
}
}