framework/data/ActiveDataProvider.php
public function setSort($value)
    {
        parent::setSort($value);
        if (($sort = $this->getSort()) !== false && $this->query instanceof ActiveQueryInterface) {
            /* @var $modelClass Model */
            $modelClass = $this->query->modelClass;
            $model = $modelClass::instance();
            if (empty($sort->attributes)) {
                foreach ($model->attributes() as $attribute) {
                    $sort->attributes[$attribute] = [
                        'asc' => [$attribute => SORT_ASC],
                        'desc' => [$attribute => SORT_DESC],
                        'label' => $model->getAttributeLabel($attribute),
                    ];
                }
            } else {
                foreach ($sort->attributes as $attribute => $config) {
                    if (!isset($config['label'])) {
                        $sort->attributes[$attribute]['label'] = $model->getAttributeLabel($attribute);
                    }
                }
            }
        }
    }
public function setSort($value)
    {
        parent::setSort($value);
        if (($sort = $this->getSort()) !== false && $this->query instanceof ActiveQueryInterface) {
            /* @var $modelClass Model */
            $modelClass = $this->query->modelClass;
            $model = $modelClass::instance();
            if (empty($sort->attributes)) {
                foreach ($model->attributes() as $attribute) {
                    $sort->attributes[$attribute] = [
                        'asc' => [$attribute => SORT_ASC],
                        'desc' => [$attribute => SORT_DESC],
                        'label' => $model->getAttributeLabel($attribute),
                    ];
                }
            } else {
                foreach ($sort->attributes as $attribute => $config) {
                    if (!isset($config['label'])) {
                        $sort->attributes[$attribute]['label'] = $model->getAttributeLabel($attribute);
                    }
                }
            }
        }
    }
{@inheritdoc}