Return value of tfproject\model\front_article::getArticleDetail() must be of the type array, null returned (0)

            }
            $articleInfo["mDatetime"] = preg_replace("/\:\d+$/", "", $articleInfo["mDatetime"]);
            $articleInfo["content"] = $mFile->decodeURIsInString(strval($articleInfo["content"]));
            $articleInfo["tags"] = $tArticleTag->getADataAll($articleInfo);
        }
        return $articleInfo;
    }
    public function getArticleDetailRelationArticles(int $articleId): array{
        $tArticle = $this->getO2O("article");
        $myTFDO = $tArticle->getTFDO();
        // get tag IDs

tfproject\model\front_article::getArticleDetail() in /var/www/html/web-inf/controller/homeDetail.inc.php line 31
tfproject\controller\homeDetail::onLoad() in /var/www/tfphp/system/tfpage.inc.php line 22
tfphp\system\tfpage::load() in /var/www/tfphp/tfphp.inc.php line 232
tfphp\tfphp::start() in /var/www/tfphp/tfphp.inc.php line 236
tfphp\tfphp::run() in /var/www/html/index.php line 24
tfproject\index::run() in /var/www/html/index.php line 27