Fails the build if any subprojects of `:libs` have dependencies in `:libs`
except for `:libs:elasticsearch-core`.
Since we now have three places where we resolve project substitutions
I've added `dependencyToProject` to `project.ext` in all projects. It
resolves both `project` style dependencies and "external" style (like
"org.elasticsearch:elasticsearch-core:${version}") dependencies to
`Project`s using the `projectSubstitutions`. I use this new function all
three places where resovle project substitutions.
Finally this pulls `apply plugin: 'elasticsearch.build'` out of
`libs/*/build.gradle` and into a subprojects clause in
`libs/build.gradle`. I do this entirely so that I can call
`tasks.precommit.dependsOn checkDependencies` without waiting for the
subprojects to be evaluated or worrying about whether or not they have
`precommit` set up in a normal way.
This commit adds the infrastructure to plugin building and loading to
allow one plugin to extend another. That is, one plugin may extend
another by the "parent" plugin allowing itself to be extended through
java SPI. When all plugins extending a plugin are finished loading, the
"parent" plugin has a callback (through the ExtensiblePlugin interface)
allowing it to reload SPI.
This commit also adds an example plugin which uses as-yet implemented
extensibility (adding to the painless whitelist).
Alpar Torok
Nik Everett
Ryan Ernst