instantiate

# File activerecord/lib/active_record/associations/join_dependency.rb, line 93
      def instantiate(result_set, &block)
        primary_key = aliases.column_alias(join_root, join_root.primary_key)

        seen = Hash.new { |i, object_id|
          i[object_id] = Hash.new { |j, child_class|
            j[child_class] = {}
          }
        }

        model_cache = Hash.new { |h, klass| h[klass] = {} }
        parents = model_cache[join_root]
        column_aliases = aliases.column_aliases join_root

        message_bus = ActiveSupport::Notifications.instrumenter

        payload = {
          record_count: result_set.length,
          class_name: join_root.base_klass.name
        }

        message_bus.instrument("instantiation.active_record", payload) do
          result_set.each { |row_hash|
            parent_key = primary_key ? row_hash[primary_key] : row_hash
            parent = parents[parent_key] ||= join_root.instantiate(row_hash, column_aliases, &block)
            construct(parent, join_root, row_hash, seen, model_cache)
          }
        end

        parents.values
      end