Unify plugin-publish plugin with java-gradle-plugin

[oehme]

From the Design Spec:

Context

Publishing Gradle plugins currently requires different plugins depending on whether one wants to publish to the Plugin Portal or a custom, e.g. company-internal, repository. For the former purpose, there’s the Plugin Publishing Plugin (com.gradle.plugin-publish); for the latter, there’s the Gradle Plugin Development Plugin (java-gradle-plugin).

When a project wants to publish Gradle plugins to both the Plugin Portal and a custom Maven repository or simply use the Gradle Plugin Development Plugin to generate the plugin descriptors, its build script currently requires some duplication:

• the plugin IDs have to be duplicated in the plugins blocks of gradlePlugin and pluginBundle
• the maven coordinates have to customized twice (in mavenCoordinates of pluginBundle and in the pluginMaven publication).

Moreover, the Plugin Publishing Plugin generates a separate POM file and does not take into account any customizations made to the POM of the main publication added by the Gradle Plugin Development Plugin.

Goal

Simplify publishing to the Plugin Portal and a custom repository to avoid duplication and enable reuse of POM customization.

[marcphilipp]

I wrote a design spec and updated the issue description with its main points. Comments on the design spec are welcome!

[marcphilipp]

plugin-publish 0.10.0 has been released, the changes to the java-gradle-plugin plugin will be in 4.10.

[jmini]

If anyone is interested, @marcphilipp wrote this little example to demonstrate how to use this feature with the Groovy DSL:
https://github.com/marcphilipp/gradle-sandbox/blob/85e934d13b413df2fccd752591f631128e7e7734/plugin-maven-publish/build.gradle#L23-L44