- name: fail if role is not defined
  fail:
    msg: this_role variable is not defined or is not an object
  when: this_role is not mapping


- name: include role
  include_role:
    name: "{{ this_role.role }}"
    public: "{{ this_role.public | d(false) }}"
    tasks_from: "{{ this_role.tasks_from | d(omit) }}"
  vars:
    function: "{{ this_role.function | d(None) }}"