construct

# File activerecord/lib/active_record/associations/join_dependency.rb, line 242
        def construct(ar_parent, parent, row, seen, model_cache, strict_loading_value)
          return if ar_parent.nil?

          parent.children.each do |node|
            if node.reflection.collection?
              other = ar_parent.association(node.reflection.name)
              other.loaded!
            elsif ar_parent.association_cached?(node.reflection.name)
              model = ar_parent.association(node.reflection.name).target
              construct(model, node, row, seen, model_cache, strict_loading_value)
              next
            end

            if node.primary_key
              keys = Array(node.primary_key).map { |column| aliases.column_alias(node, column) }
              ids = keys.map { |key| row[key] }
            else
              keys = Array(node.reflection.join_primary_key).map { |column| aliases.column_alias(node, column.to_s) }
              ids = keys.map { nil } # Avoid id-based model caching.
            end

            if keys.any? { |key| row[key].nil? }
              nil_association = ar_parent.association(node.reflection.name)
              nil_association.loaded!
              next
            end

            ids.each do |id|
              unless model = seen[ar_parent][node][id]
                model = construct_model(ar_parent, node, row, model_cache, id, strict_loading_value)
                seen[ar_parent][node][id] = model if id
              end
            end

            construct(model, node, row, seen, model_cache, strict_loading_value)
          end
        end