Trying to access array offset on value of type null (8)

                inner join tfart_article_tag at 
                on a.mId = at.mId
                where a.mStat = @int
                and at.cId = @int
                order by a.mReadC desc";
            $params = [1, $tag["cId"]];
        }
        $articles = $ds->fetchMany3($sql, $params, 0, 10);
        if($articles === null) $articles = [];
        return $articles;
    }

tfphp\tfdumpError() in /var/www/html/web-inf/model/articleFront.inc.php line 160
tfproject\model\articleFront::getBlogHotArticles() in /var/www/html/web-inf/controller/tag.inc.php line 24
tfproject\controller\tag::onLoad() in /var/www/tfphp/dist/system/tfpage.inc.php line 22
tfphp\system\tfpage::load() in /var/www/tfphp/dist/tfphp.inc.php line 221
tfphp\tfphp::start() in /var/www/tfphp/dist/tfphp.inc.php line 225
tfphp\tfphp::run() in /var/www/html/index.php line 31
tfproject\index::run() in /var/www/html/index.php line 34