Add a concept of "root" package/s

[mdedetrich]

This issue is about creating the concept of a "root" package. The definition of a root package is one where all other packages are nested under it? As an example in Pekko we would have org.apache.pekko as a "root" package since all scala code placed under org.apache.root.

Such a concept is useful primarily for reducing code boilerplate, i.e. this pattern is already being used in Pekko (see https://github.com/apache/incubator-pekko/blob/1612950702d4dc8107f336442c7617cc67e22eda/remote/src/main/scala/org/apache/pekko/remote/FailureDetectorRegistry.scala as an example) because otherwise would literally have cases where when referring to a type/class/import etc etc if we used the fully qualified name, that byitself would just take up half the screen.

The premise of the issue is to create a concept of root packages, i.e. in your .scalafix.conf you would have something like this

root-packages = [
  "org.apache.pekko",
  "org.apache.kafka"
]

And then other rules/rewrites would use that if relevant/necessary. So far the main rule that I can think of where this is relevant is OrganizeImports and there is already a ticket on this at liancheng/scalafix-organize-imports#312 but there may be some cases which I am missing.

[bjaglin]

Thanks for the detailled report(s) @mdedetrich!

Since .scalafix.conf is parsed as HOCON (through metaconfig), any block that is meant to be repeated can be declared in an arbitrary key and referenced wherever needed, as showcased here.

As a result, I will close this as it seems good enough to handle your (speculated) use-case, without the need to introduce a new paradigm for configuring rules. Let's focus on the OrganizeImports use case.