class ChefCLI::Command::Diff

def parse_server_comparison(args)
  comparison_string = args.last
  if comparison_string.include?("...")
    old_pgroup, new_pgroup, *extra = comparison_string.split("...")
    @old_base, @new_base = [old_pgroup, new_pgroup].map do |g|
      Policyfile::ComparisonBase::PolicyGroup.new(g, policy_name, http_client)
    end
    unless extra.empty?
      ui.err("Unable to parse policy group comparison `#{comparison_string}`. Only 2 references can be specified.")
      return false
    end
  else
    @old_base = Policyfile::ComparisonBase::PolicyGroup.new(comparison_string, policy_name, http_client)
    @new_base = Policyfile::ComparisonBase::Local.new(policyfile_lock_relpath)
  end
  true
end