_media_brightcove_cron() publishes old node revisions, misuses db_query_range().

This cron hook has a bug causing its query to return 0 hits (no matter what) on every other call.

Code, for reference:

  // We need to collect any metadata that is missing from node fields.
  $limit = media_brightcove_variable_get('cron_limit');
  $start = media_brightcove_variable_get('cron_start');
  $end = 0;
  $nodes = array();
  $results = db_query_range("SELECT nid, vid, field_name, delta, uri FROM {media_brightcove_fields} WHERE data_collected = 0 ORDER BY vid, field_name, delta", $start, $limit);

  // First collect any missing metadata.
  while ($result = db_fetch_object($results)) {
    $data = media_brightcove_data($result->uri, TRUE);

    // If we now have data, then load the node and add it.
    if (!empty($data)) {
      if (!isset($nodes[$result->nid])) {
        $nodes[$result->nid] = array();
      }
      // Load this revision if we haven't already.
      $nodes[$result->nid][$result->vid] = isset($nodes[$result->nid][$result->vid]) ? $nodes[$result->nid][$result->vid] : node_load($result->nid, $result->vid);
      if (isset($nodes[$result->nid][$result->vid]->{$result->field_name}[$result->delta]['value'])) {
        // Set the data for this field. Note this is only applicable to emvideo.
        $nodes[$result->nid][$result->vid]->{$result->field_name}[$result->delta]['data'] = $data;
        $nodes[$result->nid][$result->vid]->{$result->field_name}[$result->delta]['duration'] = media_brightcove_duration($result->uri);
        $nodes[$result->nid][$result->vid]->{$result->field_name}[$result->delta]['status'] = media_brightcove_video_available($result->uri);
        $nodes[$result->nid][$result->vid]->{$result->field_name}[$result->delta]['version'] = MEDIA_BRIGHTCOVE_DATA_VERSION;
      }
    }
  }

  // Now go through each revision and save it.
  foreach ($nodes as $revisions) {
    foreach ($revisions as $node) {
      // Save the newly collected data into the revision.
      node_save($node);
      // Store the current progress.
      $end = $node->vid;
      media_brightcove_variable_set('cron_start', $end);
    }
  }

  // Ensure we set back to 0 after reaching the end of it all.
  media_brightcove_variable_set('cron_start', $end);

The last line stores a node vid in the "cron_start" variable at the end; the next time through the function, this vid gets passed as the $from parameter to db_query_range(). That's not how $from works. Maybe this last line was supposed to save a 0; the comment seems to imply that.

Forgetting this bug, why is cron_start needed at all? Every time you update a node, its "data_collected" field will get set to 1 (during node_save()), so it won't get selected again during the next cron hook (right?). So this function should never need to pass non-zero as $from to db_query_range()....