babashka.bash

vagrant@local /vagrant $ babashka vm
 -> vm
  -> docker
  `- is met?
    0
vagrant@local /vagrant $ echo $?
1

docker.sh

docker() {
  is_met() {
    which docker 2>/dev/null
  }

  meet() {
    pkg_name=app-emulation/docker
    sudo emerge $pkg_name --autounmask-write
    sudo etc-update --automode -3
    sudo emerge $pkg_name
  }

  process
}

vm.sh

vm() {
  requires docker
}

Yeah, definitely bug.

It's a good bug :) It even led me to write my provisioner like this, for added clarity:

(cd /vagrant && babashka vm; [[ $? = 1 ]])