    # File lib/chef/node.rb, line 441
        def expand!(data_source = 'server')
          expansion = run_list.expand(chef_environment, data_source)
          raise Chef::Exceptions::MissingRole if expansion.errors?

          self.tags # make sure they're defined

          @automatic_attrs[:recipes] = expansion.recipes
          @automatic_attrs[:roles] = expansion.roles

          expansion
        end