Staging does not clear out previous files

[huntc]

Stage should ensure that the files in the staging folder are part of the current build only, and not left over from previous builds. Perhaps sbt's sync functionality should be utilised when copying files to this folder.

Related to playframework/playframework#2418

[benmccann]

Just FYI, it takes almost no time to blast away the directory and recreate it, so if that's easier it should be a sufficient solution.

[huntc]

Sure, but with sbt's sync functionality and a very large project, it may make a difference. The sync functionality is also quite easy to use.

[benmccann]

Cool. As long as it's easy :-)

[huntc]

Some similar code:

  private def syncMappings(cacheDir: File, mappings: Seq[PathMapping], target: File): File = {
    val cache = cacheDir / "sync-mappings"
    val copies = mappings map {
      case (file, path) => file -> (target / path)
    }
    Sync(cache)(copies)
    target
  }

[muuki88]

@aparkinson do you have some time for this? I will be bit busy the next week(s) :(