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.
* Splits nio project into two for eclipse build only
https://github.com/elastic/elasticsearch/pull/27801 introduced a new gradle project `:libs:elasticsearch-nio` which creates cyclical project dependencies when importingthe projects into Eclipse.
This change applies the same trick as we have for the core project where, and building for Eclipse, splits the `:libs:elasticsearch-nio` project into `:libs:elasticsearch-nio` which points to `src/main` and `:libs:elasticsearch-nio-tests` which points to `src/test`. This prevents cyclical project dependencies in Eclipse arising from the fact that eclipse does not separate compile/runtime dependencies from test dependencies.
* Removes integTest bits since there are none
This is related to #27802. This commit adds a jar called
elasticsearch-nio that contains the base nio classes that will be used
for the tcp nio transport and eventually the http nio transport.
The jar does not depend on elasticsearch:core, so all references to core
have been removed.