# File lib/chef/run_list/run_list_expansion.rb, line 58
      def initialize(environment, run_list_items, source=nil)
        @environment = environment
        @missing_roles_with_including_role = Array.new

        @run_list_items = run_list_items.dup
        @source = source

        @default_attrs = Mash.new
        @override_attrs = Mash.new

        @recipes = Chef::RunList::VersionedRecipeList.new

        @applied_roles = {}
        @run_list_trace = Hash.new {|h, key| h[key] = [] }
      end