Call to a member function getArticleComments() on null
1. in /var/www/example.com/basic/controllers/SiteController.php at line 143


    public function actionView($id)
    {
        $article = Article::findOne($id);
        $popular = Article::getPopular();
        $recent = Article::getRecent();
        $categories = Category::getAll();
        $comments = $article->getArticleComments();   -- line 143
        $commentForm = new CommentForm();
        $article->viewedCounter();

        return $this->render('single',[
            'article'=>$article,
            'popular'=>$popular,
            'recent'=>$recent,
            'categories'=>$categories,
            'comments'=>$comments,
     //
Трассировка стека:

Error: Call to a member function getArticleComments() on null in /var/www/example.com/basic/controllers/SiteController.php:143
Stack trace:
#0 [internal function]: app\controllers\SiteController->actionView('845')
#1 /var/www/example.com/basic/vendor/yiisoft/yii2/base/InlineAction.php(57): call_user_func_array(Array, Array)
#2 /var/www/example.com/basic/vendor/yiisoft/yii2/base/Controller.php(157): yii\base\InlineAction->runWithParams(Array)
#3 /var/www/example.com/basic/vendor/yiisoft/yii2/base/Module.php(528): yii\base\Controller->runAction('view', Array)
#4 /var/www/example.com/basic/vendor/yiisoft/yii2/web/Application.php(103): yii\base\Module->runAction('site/view', Array)
#5 /var/www/example.com/basic/vendor/yiisoft/yii2/base/Application.php(386): yii\web\Application->handleRequest(Object(yii\web\Request))
#6 /var/www/example.com/basic/web/index.php(12): yii\base\Application->run()
#7 {main}