construct_join_attributes

# File activerecord/lib/active_record/associations/through_association_scope.rb, line 100
      def construct_join_attributes(associate)
        # TODO: revisit this to allow it for deletion, supposing dependent option is supported
        raise ActiveRecord::HasManyThroughCantAssociateThroughHasOneOrManyReflection.new(@owner, @reflection) if [:has_one, :has_many].include?(@reflection.source_reflection.macro)

        join_attributes = construct_owner_attributes(@reflection.through_reflection).merge(@reflection.source_reflection.primary_key_name => associate.id)

        if @reflection.options[:source_type]
          join_attributes.merge!(@reflection.source_reflection.options[:foreign_type] => associate.class.base_class.name.to_s)
        end

        if @reflection.through_reflection.options[:conditions].is_a?(Hash)
          join_attributes.merge!(@reflection.through_reflection.options[:conditions])
        end

        join_attributes
      end