JRubyExec should support "watch" configuration

[rtyler]

I don't think we can do this today with TaskInputs, but the option of watch on JRubyExec would be a great way to provide file or directory task inputs for a JRubyExec task.

For rspec, it might look something like this:

task spec(type: JRubyExec) {
  description 'Execute RSpec against spec/**/*.rb'
  script 'rspec'
  watch 'spec/'
}

And the user would be able to use ./gradlew -t spec to take advantage of Gradle's continuous building functionality.

[ysb33r]

It should be possible as long as rspec is annotated @InputFile. Currently we do some other manipulations as the script file could actually be contained in the GEM and that is why it is not annotated as such.

[rtyler]

@ysb33r the script is already annotated as an @InputFile, but that is not what will be changing during the development of tests. In a Rails application for example, file changes would be happening in app/ and spec/ directories, and when those directories have file changes, I would want the task to re-execute.

I believe it's just a question of plugging the right inputs into the underlying gradle task inputs subsystem

[ysb33r]

@rtyler that is not a really a feature of the JRubyExec. It is very contextual to someone wanting to run Rails from a JRubyExec task. The simplest for someone would be to do inputs.dirs 'app', 'spec' in their build script.

However if the layout is very common, then we could add a helper method that automatically adds those directories to the inputs of the JRubyExec task i.e. 'dependsOnRails()`

[rtyler]

@ysb33r I was describing the Rails scenario as an example. What I'm proposing is basically inputs.dir syntax sugar in the phrasing (watch) that is familiar to most Ruby developers.

[ysb33r]

@rtyler Got ya. Makes sense now.