join_constraints

# File activerecord/lib/active_record/associations/join_dependency.rb, line 77
      def join_constraints(joins_to_add, alias_tracker)
        @alias_tracker = alias_tracker

        construct_tables!(join_root)
        joins = make_join_constraints(join_root, join_type)

        joins.concat joins_to_add.flat_map { |oj|
          construct_tables!(oj.join_root)
          if join_root.match? oj.join_root
            walk(join_root, oj.join_root, oj.join_type)
          else
            make_join_constraints(oj.join_root, oj.join_type)
          end
        }
      end