Share tasks between normal and meta-build

[denisrosca]

I have a task that reads a value from env variables looks something like this:

  def languageServerVersionOverride: T[Option[String]] = Task.Input {
    T.ctx().env.get("LS_VERSION")
  }

and I need to be able to access it in both the normal and the meta build.

Previously (with version 0.11.13) I could just define the task in a ./mill-build/utils.sc file and import it in both ./build.sc and ./mill-build/build.sc.

After moving to 0.12.7 and having to "encapsulate" the task into a module trait, that no longer works:

package build 

import mill._
import mill.Module

trait Versions extends Module {
  def languageServerVersionOverride: T[Option[String]] = Task.Input {
    T.ctx().env.get("SMITHY_LS_VERSION")
  }
}

I can import it into my meta-build just fine:

package build

import $file.versions

import mill._
import versions.Versions

object `package` extends MillBuildRootModule with Versions

but I can't for the life of me figure out how to import it into my normal build.mill.