Add Maven Descriptor Gradle Plugin

When Maven builds a jar, by default the Maven Archiver includes the Maven descriptor information. This is the pom.xml file at META-INF/maven/${groupId}/${artifactId}/pom.xml and the pom.properties file at META-INF/maven/${groupId}/${artifactId}/pom.properties.

These resources are useful to have in jars when they are standing alone and disconnected from a repository.

Gradle's Jar task type does not include Maven descriptor information in built jars. So this plugin was created to add the Maven descriptor information to built jars.

Configuring the plugin

The simplest way to use the plugin is to apply to your project.

plugins {
  id "dev.hargrave.addmavendescriptor" version "1.1.0"
}

The addmavendescriptor plugin will apply the maven-publish plugin if it is not already applied. The maven-publish plugin is used as the Maven descriptor information source. A MavenPublication must be configured to define the Maven descriptor information which includes the groupId and artifactId.

publishing {
  publications {
    maven(MavenPublication) {
      pom {
        // Configure pom elements
      }
    }
  }
}

If no MavenPublication is defined, then the addmavendescriptor plugin does nothing. So it is safe to apply to a project which does not define a MavenPublication.

When only a single MavenPublication is defined, the addmavendescriptor plugin will automatically use it to obtain the Maven descriptor information and the pom file generator task defined by the maven-publish plugin when the MavenPublication is defined. The addmavendescriptor plugin will define a pom properties file generator task for the MavenPublication and also configure all the Jar tasks to include the generated pom file and the generated pom properties file.

If multiple MavenPublications are defined, then you will need to tell the addmavendescriptor plugin which one to use for the Maven descriptor information. This can be done at the project level and/or at the Jar task level. The addmavendescriptor plugin adds an addMavenDescriptor extension to the project and to each Jar task. So you can configure the name of the MavenPublication to use:

addMavenDescriptor {
  publicationName = "maven"
}

The configuration at the project level is used by all the Jar tasks unless you set the publicationName in the Jar task.

tasks.named("jar") {
  addMavenDescriptor {
    publicationName = "maven"
  }
}

Finally, if you have a Jar task, or project, in which you don't want Maven descriptor, you can set publicationName to null to disable adding the maven descriptor.

tasks.named("jar") {
  addMavenDescriptor {
    publicationName = null
  }
}

Gradle Version

This plugin requires at least Gradle 6.1 for Java 8 to Java 15, at least Gradle 7.0 for Java 16, at least Gradle 7.3 for Java 17, at least Gradle 7.5 for Java 18, at least Gradle 7.6 for Java 19, and at least Gradle 8.1 for Java 20.