        def _update_row(attribute_names, attempted_action = "update")
          return super unless locking_enabled?
          return super if attempted_action == "touch" && _skip_locking_column_on_touch?

          begin
            locking_column = self.class.locking_column
            lock_attribute_was = @attributes[locking_column]

            update_constraints = _query_constraints_hash

            attribute_names = attribute_names.dup if attribute_names.frozen?
            attribute_names << locking_column

            if self[locking_column].nil?
              raise(<<-MSG.squish)
                For optimistic locking, locking_column ('#{locking_column}') can't be nil.
                Are you missing a default value or validation on '#{locking_column}'?
              MSG
            end

            self[locking_column] += 1

            affected_rows = self.class._update_record(
              attributes_with_values(attribute_names),
              update_constraints
            )

            if affected_rows != 1
              raise ActiveRecord::StaleObjectError.new(self, attempted_action)
            end

            affected_rows

          # If something went wrong, revert the locking_column value.
          rescue Exception
            @attributes[locking_column] = lock_attribute_was
            raise
          end
        end
…
        def _query_constraints_hash
          return super unless locking_enabled?

          locking_column = self.class.locking_column
          super.merge(locking_column => _lock_value_for_database(locking_column))
        end

Échauffement