Code Changes

		// If the topic no longer exist, we will update the topic watch table.
		// To not let it error out on users watching both topics, we just return on an error...
		$db->sql_return_on_error(true);
		$db->sql_query('UPDATE ' . TOPICS_WATCH_TABLE . ' SET topic_id = ' . (int) $to_topic_id . ' WHERE ' . $db->sql_in_set('topic_id', $topic_ids));
		$db->sql_return_on_error(false);

		if (!function_exists('phpbb_update_rows_avoiding_duplicates_notify_status'))
		{
			include($phpbb_root_path . 'includes/functions_database_helper.' . $phpEx);
		}

		$db->sql_query('DELETE FROM ' . TOPICS_WATCH_TABLE . ' WHERE ' . $db->sql_in_set('topic_id', $topic_ids));

		// Update the topic watch table.
		phpbb_update_rows_avoiding_duplicates_notify_status($db, TOPICS_WATCH_TABLE, 'topic_id', $topic_ids, $to_topic_id);

		// Update the bookmarks table.
		phpbb_update_rows_avoiding_duplicates($db, BOOKMARKS_TABLE, 'topic_id', $topic_ids, $to_topic_id);