lib/beaker-pe/install/feature_flags.rb
def register_flags!
      answers_with_registered_flags = answers
      answers_with_registered_flags[:feature_flags] ||= StringifyHash.new
      new_flags = answers_with_registered_flags[:feature_flags]

      FLAGS.each do |flag|
        key = canonical_key(flag)
        value = flag?(key)
        if !new_flags.include?(key) && !value.nil?
          new_flags[key] = value
        end
      end

      options.merge!(
        :answers => answers_with_registered_flags
      ) if !new_flags.empty?

      options
    end
def register_flags!
      answers_with_registered_flags = answers
      answers_with_registered_flags[:feature_flags] ||= StringifyHash.new
      new_flags = answers_with_registered_flags[:feature_flags]

      FLAGS.each do |flag|
        key = canonical_key(flag)
        value = flag?(key)
        if !new_flags.include?(key) && !value.nil?
          new_flags[key] = value
        end
      end

      options.merge!(
        :answers => answers_with_registered_flags
      ) if !new_flags.empty?

      options
    end
Updates options[:answers][:feature_flags] with any environment variables
 found based on FLAGS, but if and only if they are not already present.

 (existing :answers take precedence)