Validation error on custom model attributes not displayed in form - yii2

Question

I have a model with the following custom attributes topic_names, topic_details (string fields). I have also a model form with the custom attributes and custom rules. When I insert wrong data in the form fields, there is a model error, but it isn't displayed.
Model code:
......
public function rules()
{
return [
...
[['topics_names','topics_details'],'string'],
[['topics_names'],'checkCorrectAndSetTopics'],
];
}
public function checkCorrectAndSetTopics(){
if($this->topics_names AND $this->topics_details){
$topicsNamesArray = explode(',',$this->topics_names);
$topicsDetailsArray = explode(';',$this->topics_details);
if(sizeof($topicsNamesArray) !== sizeof($topicsDetailsArray)){
$this->addError('topics_names', \Yii::t('app', 'The topics names and details sets have different sizes'));
return FALSE;
}
}
return TRUE;
}
The problem is when the second rules is violeted, the form doesn't show any error, but there is. I checked it debugging the code below.
Form code:
..........
<?php
ActiveForm::$autoIdPrefix = createRandomId();//Function which creates a random id
$form = ActiveForm::begin(
['enableAjaxValidation' => true, "options"=> ["class"=>"extra-form"]]);
?>
<?= $form->errorSummary($model); ?>
<?= $form->field($model, 'topics_names')->textInput()
->label(\Yii::t('app', 'Topics Names'))?>
<?= $form->field($model, 'topics_details')->textarea(['rows' => 6])
->label(\Yii::t('app', 'Topics Details'))?>
........
Controller code:
public function actionAddExtraData($id){
if(!Yii::$app->request->isAjax){
throw new ForbiddenHttpException(\Yii::t('app','Cannot access this action directly.'));
}
$event = $this->findModel($id);
$extraData = ExtraData::find()
->andWhere(['event_id'=>$id])
->one();
if(!$extraData){
$extraData = new ExtraData();
$extraData->event_id = $id;
}else{
$extraData->prePerformForm();//Insert data on custom attributes
}
if(Yii::$app->request->isPost AND Yii::$app->request->isAjax AND Yii::$app->request->post("submitting") != TRUE
AND $extraData->load(Yii::$app->request->post())){
Yii::$app->response->format = Response::FORMAT_JSON;
$validation = ActiveForm::validate($extraData);
return $validation;
}
if ($extraData->load(Yii::$app->request->post()) && $extraData->save()) {
if (Yii::$app->request->isAjax) {
Yii::$app->response->format = Response::FORMAT_JSON;
return ["success" => TRUE];
} else {
return $this->redirect(Yii::$app->request->referrer);
}
}
return $this->renderAjax('_event_extra_form',['model'=>$extraData,'event'=>$event]);
}

Answer 1

First thing, pretty sure you don't need to return true or false, you just need to add error. Second thing, in your example you name the attribute, you can actually get this when defining the function, so your function could look something like this
public function checkCorrectAndSetTopics($attribute, $model){
if($this->topics_names AND $this->topics_details){
$topicsNamesArray = explode(',',$this->topics_names);
$topicsDetailsArray = explode(';',$this->topics_details);
if(sizeof($topicsNamesArray) !== sizeof($topicsDetailsArray)){
$this->addError($attribute, \Yii::t('app', 'The topics names and details sets have different sizes'));
}
}
}