Function doRectify

common/models/change.js:223–265

(checkpoint, rev)

    }

    function doRectify(checkpoint, rev) {
      if (rev) {
        if (currentRev === rev) {
          change.debug('ASSERTION FAILED: Change currentRev==rev ' +
            'should have been already handled');
          return cb(null, change);
        } else {
          change.rev = rev;
          change.debug('updated revision (was ' + currentRev + ')');
          if (change.checkpoint !== checkpoint) {
            // previous revision is updated only across checkpoints
            change.prev = currentRev;
            change.debug('updated prev');
          }
        }
      } else {
        change.rev = null;
        change.debug('updated revision (was ' + currentRev + ')');
        if (change.checkpoint !== checkpoint) {
          // previous revision is updated only across checkpoints
          if (currentRev) {
            change.prev = currentRev;
          } else if (!change.prev) {
            change.debug('ERROR - could not determine prev');
            change.prev = Change.UNKNOWN;
          }
          change.debug('updated prev');
        }
      }

      if (change.checkpoint != checkpoint) {
        debug('update checkpoint to', checkpoint);
        change.checkpoint = checkpoint;
      }

      if (change.prev === Change.UNKNOWN) {
        // this occurs when a record of a change doesn't exist
        // and its current revision is null (not found)
        change.remove(cb);
      } else {
        change.save(cb);
      }
    }
  };

  /**