How can I publish a javadoc.jar file with my Kotlin multiplatform project?

Note: I have posted this question at Stack Overflow already, but I want to increase my chances of getting a reply for this niche topic by posting here. If you want credit, please reply over there.

Related topics/issues:
- How to configure Dokka for kotlin-multiplatform
- Dokka Javadoc plugin currently does not support generating documentation for multiplatform project

I am trying to publish my Kotlin multiplatform library to Maven Central via Sonatype. This repository requires me to include a javadoc.jar file with my artifacts. Unfortunately, the IntelliJ IDEA project wizard and the Kotlin multiplatform docs do not help me do that. When running the Gradle task dokkaJavadoc (for the official Kotlin documentation tool Dokka), I get the error “Dokka Javadoc plugin currently does not support generating documentation for multiplatform project.”

I actually do not need genuine JavaDocs for publishing - an empty javadoc.jar or one with other docs generated by Dokka would suffice. Since I have been a longtime Maven user and these are my first steps with Gradle, I have no idea how to do that.

build.gradle.kts:

plugins {
    kotlin("multiplatform") version "1.4.31"
    id("org.jlleitschuh.gradle.ktlint") version "10.0.0"
    id("io.gitlab.arturbosch.detekt") version "1.15.0"
    id("org.jetbrains.dokka") version "1.4.20"
    id("maven-publish")
    signing
}

group = "com.marcoeckstein"
version = "0.0.3-SNAPSHOT"

publishing {
    publications {
        create<MavenPublication>("maven") {
            pom {
                val projectGitUrl = "https://github.com/marco-eckstein/kotlin-lib"
                name.set(rootProject.name)
                description.set(
                    "A general-purpose multiplatform library. " +
                        "Implemented in Kotlin, usable also from Java, JavaScript and more."
                )
                url.set(projectGitUrl)
                inceptionYear.set("2021")
                licenses {
                    license {
                        name.set("MIT")
                        url.set("https://opensource.org/licenses/MIT")
                    }
                }
                developers {
                    developer {
                        id.set("marcoeckstein.com")
                        name.set("Marco Eckstein")
                        email.set("marco.eckstein@gmx.de")
                        url.set("https://www.marcoeckstein.com")
                    }
                }
                issueManagement {
                    system.set("GitHub")
                    url.set("$projectGitUrl/issues")
                }
                scm {
                    connection.set("scm:git:$projectGitUrl")
                    developerConnection.set("scm:git:$projectGitUrl")
                    url.set(projectGitUrl)
                }
            }
        }
    }
    repositories {
        maven {
            name = "sonatypeStaging"
            url = uri("https://oss.sonatype.org/service/local/staging/deploy/maven2")
            credentials(PasswordCredentials::class)
        }
    }
}

signing {
    useGpgCmd()
    sign(publishing.publications["maven"])
}

repositories {
    mavenCentral()
    jcenter()
}

kotlin {
    targets.all {
        compilations.all {
            kotlinOptions {
                allWarningsAsErrors = true
            }
        }
    }
    jvm {
        compilations.all {
            kotlinOptions.jvmTarget = "11"
        }
        testRuns["test"].executionTask.configure {
            useJUnitPlatform()
        }
    }
    js(BOTH) {
        browser {
            testTask {
                useKarma {
                    useChromeHeadless()
                    webpackConfig.cssSupport.enabled = true
                }
            }
        }
    }
    val hostOs = System.getProperty("os.name")
    val isMingwX64 = hostOs.startsWith("Windows")
    val nativeTarget = when {
        hostOs == "Mac OS X" -> macosX64("native")
        hostOs == "Linux" -> linuxX64("native")
        isMingwX64 -> mingwX64("native")
        else -> throw GradleException("Host OS is not supported in Kotlin/Native.")
    }

    sourceSets {
        val commonMain by getting
        val commonTest by getting {
            dependencies {
                implementation(kotlin("test-common"))
                implementation(kotlin("test-annotations-common"))
                implementation("io.kotest:kotest-assertions-core:4.4.1")
            }
        }
        val jvmMain by getting
        val jvmTest by getting {
            dependencies {
                implementation(kotlin("test-junit5"))
                implementation("org.junit.jupiter:junit-jupiter-api:5.6.0")
                runtimeOnly("org.junit.jupiter:junit-jupiter-engine:5.6.0")
            }
        }
        val jsMain by getting
        val jsTest by getting {
            dependencies {
                implementation(kotlin("test-js"))
            }
        }
        val nativeMain by getting
        val nativeTest by getting
    }
}

configure<org.jlleitschuh.gradle.ktlint.KtlintExtension> {
    enableExperimentalRules.set(true)
    verbose.set(true)
    // ktlint.disabled_rules:
    // filename:
    // Caught more precisely (with desired exceptions) with detekt.
    // import-ordering:
    // ktlint's order is not supported (yet) by IntelliJ.
    // See:
    // - https://github.com/pinterest/ktlint/issues/527
    // - https://youtrack.jetbrains.com/issue/KT-10974
    // no-wildcard-imports:
    // Not desired. We want them for Java statics and Enum members.
    // experimental:annotation:
    // Not desired.
    // experimental:multiline-if-else:
    // Not desired.
    disabledRules.set(
        setOf(
            "filename",
            "import-ordering",
            "no-wildcard-imports",
            "experimental:annotation",
            "experimental:multiline-if-else"
        )
    )
    additionalEditorconfigFile.set(file("$projectDir/.editorconfig"))
}

detekt {
    input = files("$projectDir/src/")
    config = files("$projectDir/detekt-config.yml")
    buildUponDefaultConfig = true
}

tasks {
    withType<io.gitlab.arturbosch.detekt.Detekt> {
        // Target version of the generated JVM bytecode. It is used for type resolution.
        jvmTarget = "11"
    }
}

might something as simple as:

java {
    withJavadocJar()
}

suffice?

Yeah I was facing this issue few days ago for kotlingram and in the end I literally put the same Dokka HTML in each publication and it works!

Have a look here how I’ve done it!

2 Likes

No. I get the error “SourceSet with name ‘main’ not found.”

Thanks a lot! I noticed I had another issue related to publishing, but given your code I could resolve all publishing-related issues:

plugins {
    kotlin("multiplatform") version "1.4.31"
    id("org.jlleitschuh.gradle.ktlint") version "10.0.0"
    id("io.gitlab.arturbosch.detekt") version "1.15.0"
    id("org.jetbrains.dokka") version "1.4.20"
    id("maven-publish")
    signing
}

group = "com.marcoeckstein"
version = "0.0.3"

val dokkaHtml by tasks.getting(org.jetbrains.dokka.gradle.DokkaTask::class)

val javadocJar: TaskProvider<Jar> by tasks.registering(Jar::class) {
    dependsOn(dokkaHtml)
    archiveClassifier.set("javadoc")
    from(dokkaHtml.outputDirectory)
}

publishing {
    publications.withType<MavenPublication> {
        artifact(javadocJar)
        pom {
            val projectGitUrl = "https://github.com/marco-eckstein/kotlin-lib"
            name.set(rootProject.name)
            description.set(
                "A general-purpose multiplatform library. " +
                    "Implemented in Kotlin, usable also from Java, JavaScript and more."
            )
            url.set(projectGitUrl)
            inceptionYear.set("2021")
            licenses {
                license {
                    name.set("MIT")
                    url.set("https://opensource.org/licenses/MIT")
                }
            }
            developers {
                developer {
                    id.set("marcoeckstein.com")
                    name.set("Marco Eckstein")
                    email.set("marco.eckstein@gmx.de")
                    url.set("https://www.marcoeckstein.com")
                }
            }
            issueManagement {
                system.set("GitHub")
                url.set("$projectGitUrl/issues")
            }
            scm {
                connection.set("scm:git:$projectGitUrl")
                developerConnection.set("scm:git:$projectGitUrl")
                url.set(projectGitUrl)
            }
        }
        the<SigningExtension>().sign(this)
    }
    repositories {
        maven {
            name = "sonatypeStaging"
            url = uri("https://oss.sonatype.org/service/local/staging/deploy/maven2")
            credentials(PasswordCredentials::class)
        }
    }
}

signing {
    useGpgCmd()
}

repositories {
    mavenCentral()
    jcenter()
}

kotlin {
    targets.all {
        compilations.all {
            kotlinOptions {
                allWarningsAsErrors = true
            }
        }
    }
    jvm {
        compilations.all {
            kotlinOptions.jvmTarget = "11"
        }
        testRuns["test"].executionTask.configure {
            useJUnitPlatform()
        }
    }
    js(BOTH) {
        browser {
            testTask {
                useKarma {
                    useChromeHeadless()
                    webpackConfig.cssSupport.enabled = true
                }
            }
        }
    }
    val hostOs = System.getProperty("os.name")
    val isMingwX64 = hostOs.startsWith("Windows")
    val nativeTarget = when {
        hostOs == "Mac OS X" -> macosX64("native")
        hostOs == "Linux" -> linuxX64("native")
        isMingwX64 -> mingwX64("native")
        else -> throw GradleException("Host OS is not supported in Kotlin/Native.")
    }

    sourceSets {
        val commonMain by getting
        val commonTest by getting {
            dependencies {
                implementation(kotlin("test-common"))
                implementation(kotlin("test-annotations-common"))
                implementation("io.kotest:kotest-assertions-core:4.4.1")
            }
        }
        val jvmMain by getting
        val jvmTest by getting {
            dependencies {
                implementation(kotlin("test-junit5"))
                implementation("org.junit.jupiter:junit-jupiter-api:5.6.0")
                runtimeOnly("org.junit.jupiter:junit-jupiter-engine:5.6.0")
            }
        }
        val jsMain by getting
        val jsTest by getting {
            dependencies {
                implementation(kotlin("test-js"))
            }
        }
        val nativeMain by getting
        val nativeTest by getting
    }
}

configure<org.jlleitschuh.gradle.ktlint.KtlintExtension> {
    enableExperimentalRules.set(true)
    verbose.set(true)
    // ktlint.disabled_rules:
    // filename:
    // Caught more precisely (with desired exceptions) with detekt.
    // import-ordering:
    // ktlint's order is not supported (yet) by IntelliJ.
    // See:
    // - https://github.com/pinterest/ktlint/issues/527
    // - https://youtrack.jetbrains.com/issue/KT-10974
    // no-wildcard-imports:
    // Not desired. We want them for Java statics and Enum members.
    // experimental:annotation:
    // Not desired.
    // experimental:multiline-if-else:
    // Not desired.
    disabledRules.set(
        setOf(
            "filename",
            "import-ordering",
            "no-wildcard-imports",
            "experimental:annotation",
            "experimental:multiline-if-else"
        )
    )
    additionalEditorconfigFile.set(file("$projectDir/.editorconfig"))
}

detekt {
    input = files("$projectDir/src/")
    config = files("$projectDir/detekt-config.yml")
    buildUponDefaultConfig = true
}

tasks {
    withType<io.gitlab.arturbosch.detekt.Detekt> {
        // Target version of the generated JVM bytecode. It is used for type resolution.
        jvmTarget = "11"
    }
}
1 Like