Publish Kotlin MPP metadata with Gradle Kotlin DSL - maven

Question

I have created a Kotlin MPP to share Json utilities between JVM and JS. All the code lies in the common source set and I have configured the necessary targets with their respective dependencies. Without further configuration I'm able to use the utilities from both JVM and JS but not from the common source set of another MPP, which has to do with the way Gradle handles metadata.
I already found the solution (taken from https://medium.com/xorum-io/crafting-and-publishing-kotlin-multiplatform-library-to-bintray-cbc00a4f770)
afterEvaluate {
project.publishing.publications.all {
groupId = group
if (it.name.contains('metadata')) {
artifactId = "$libraryName"
} else {
artifactId = "$libraryName-$name"
}
}
}
and I also got it to work with the Gradle Kotlin DSL:
afterEvaluate {
publishing.publications.all {
this as MavenPublication
artifactId = project.name + "-$name".takeUnless { "metadata" in name }.orEmpty()
}
}
However, this doesn't feel quite right yet.
There is no such code snippet in the official documentation.
The documentation advertises that a single dependency from the common source set should suffice to automatically resolve target specific dependencies: https://kotlinlang.org/docs/reference/building-mpp-with-gradle.html#metadata-publishing. I had to add the dependency for each target, respectively, for it to work.
this as MavenPublication is necessary because Publication has no field artifactId.
I use project.name instead of libraryName.
Is this even remotely the right way to do things or am I missing some other option which would make the whole process trivial?
Right now I'm using Kotlin 1.3.72 and Gradle 5.2.1 with enableFeaturePreview("GRADLE_METADATA") in settings.gradle.kts. I also tried it with Gradle 6.5.1 (latest) but it behaves exactly the same.
For now I'm glad that it's working at all but I suspect there is a cleaner way to do this. I'd really appreciate if someone with a bit more Gradle expertise could clear things up for me or point me into the right direction.
Edit:
gradle.build.kts for completeness. Although there isn't much going on here.
group = "org.example"
version = "1.0-SNAPSHOT"
plugins {
kotlin("multiplatform") version "1.3.72"
`maven-publish`
}
repositories {
mavenCentral()
}
kotlin {
jvm()
sourceSets {
val commonMain by getting {
dependencies {
implementation(kotlin("stdlib-common"))
}
}
val jvmMain by getting {
dependencies {
implementation(kotlin("stdlib"))
}
}
}
}

Answer 1

There wasn't really a problem after all. The solution is to simply add enableFeaturePreview("GRADLE_METADATA") to the consuming project too.
According to https://kotlinlang.org/docs/reference/building-mpp-with-gradle.html#metadata-publishing this shouldn't be necessary:
In earlier Gradle versions starting from 5.3, the module metadata is
used during dependency resolution, but publications don't include any
module metadata by default. To enable module metadata publishing, add
enableFeaturePreview("GRADLE_METADATA") to the root project's
settings.gradle file.
Weirdly it only works when both publishing project and consuming project have metadata enabled, even when both use the latest Gradle version.

Answer 2

enableFeaturePreview("GRADLE_METADATA") is enabled by default in latest gradle.
According to this you need to substitute "kotlinMultiplatform" by "" an empty string.
I finally managed to accomplish publishing to bintray with maven-publish plugin only, without outdated bintray library.
Here is my full maven.publish.gradle.kts:
import java.io.FileInputStream
import java.util.*
import org.gradle.api.publish.PublishingExtension
apply(plugin = "maven-publish")
val fis = FileInputStream("local.properties")
val properties = Properties().apply {
load(fis)
}
val bintrayUser = properties.getProperty("bintray.user")
val bintrayApiKey = properties.getProperty("bintray.apikey")
val bintrayPassword = properties.getProperty("bintray.gpg.password")
val libraryVersion: String by project
val publishedGroupId: String by project
val artifact: String by project
val bintrayRepo: String by project
val libraryName: String by project
val bintrayName: String by project
val libraryDescription: String by project
val siteUrl: String by project
val gitUrl: String by project
val licenseName: String by project
val licenseUrl: String by project
val developerOrg: String by project
val developerName: String by project
val developerEmail: String by project
val developerId: String by project
project.group = publishedGroupId
project.version = libraryVersion
afterEvaluate {
configure<PublishingExtension> {
publications.all {
val mavenPublication = this as? MavenPublication
mavenPublication?.artifactId =
"${project.name}${"-$name".takeUnless { "kotlinMultiplatform" in name }.orEmpty()}"
}
}
}
configure<PublishingExtension> {
publications {
withType<MavenPublication> {
groupId = publishedGroupId
artifactId = artifact
version = libraryVersion
pom {
name.set(libraryName)
description.set(libraryDescription)
url.set(siteUrl)
licenses {
license {
name.set(licenseName)
url.set(licenseUrl)
}
}
developers {
developer {
id.set(developerId)
name.set(developerName)
email.set(developerEmail)
}
}
organization {
name.set(developerOrg)
}
scm {
connection.set(gitUrl)
developerConnection.set(gitUrl)
url.set(siteUrl)
}
}
}
}
repositories {
maven("https://api.bintray.com/maven/${developerOrg}/${bintrayRepo}/${artifact}/;publish=1") {
credentials {
username = bintrayUser
password = bintrayApiKey
}
}
}
}
And build.gradle.kts:
plugins {
id("kotlin-multiplatform")
}
kotlin {
sourceSets {
jvm()
js() {
browser()
nodejs()
}
linuxX64()
linuxArm64()
mingwX64()
macosX64()
iosArm64()
iosX64()
val commonMain by getting {
dependencies {
}
}
val commonTest by getting {
dependencies {
implementation(kotlin("test-common"))
implementation(kotlin("test-annotations-common"))
}
}
val jsMain by getting {
dependencies {
}
}
val jsTest by getting {
dependencies {
implementation(kotlin("test-js"))
}
}
val jvmMain by getting {
dependencies {
}
}
val jvmTest by getting {
dependencies {
implementation(kotlin("test"))
implementation(kotlin("test-junit"))
}
}
val nativeMain by creating {
dependsOn(commonMain)
dependencies {
}
}
val linuxX64Main by getting {
dependsOn(nativeMain)
}
val linuxArm64Main by getting {
dependsOn(nativeMain)
}
val mingwX64Main by getting {
dependsOn(nativeMain)
}
val macosX64Main by getting {
dependsOn(nativeMain)
}
val iosArm64Main by getting {
dependsOn(nativeMain)
}
val iosX64Main by getting {
dependsOn(nativeMain)
}
}
}
apply(from = "maven.publish.gradle.kts")
Please note, there are bintray.user and bintray.apikey properties in local.properties file.
Also gradle.properties contains rest listed properties above:
libraryVersion = 0.5.22
libraryName = MultiplatformCommon
libraryDescription = Kotlin multiplatform extensions
publishedGroupId = com.olekdia
artifact = multiplatform-common
bintrayRepo = olekdia
bintrayName = multiplatform-common
siteUrl = https://gitlab.com/olekdia/common/libraries/multiplatform-common
gitUrl = https://gitlab.com/olekdia/common/libraries/multiplatform-common.git
.........
kotlin.mpp.enableGranularSourceSetsMetadata = true
systemProp.org.gradle.internal.publish.checksums.insecure = true
If you haven't created organisation in bintray you need to change in this url:
https://api.bintray.com/maven/${developerOrg}/${bintrayRepo}/${artifact}/;publish=1
developerOrg by bintrayUser, where the last one is your user name at bintray.com