handle_dependency

# File activerecord/lib/active_record/associations/has_one_association.rb, line 7
      def handle_dependency
        case options[:dependent]
        when :restrict_with_exception
          raise ActiveRecord::DeleteRestrictionError.new(reflection.name) if load_target

        when :restrict_with_error
          if load_target
            record = owner.class.human_attribute_name(reflection.name).downcase
            message = owner.errors.generate_message(:base, :'restrict_dependent_destroy.one', record: record, raise: true) rescue nil
            if message
              ActiveSupport::Deprecation.warn(                The error key `:'restrict_dependent_destroy.one'` has been deprecated and will be removed in Rails 5.1.                Please use `:'restrict_dependent_destroy.has_one'` instead..squish)
            end
            owner.errors.add(:base, message || :'restrict_dependent_destroy.has_one', record: record)
            throw(:abort)
          end

        else
          delete
        end
      end