Idea: avoid double declare link and type of relation if used via()

#14238
What about AR function?
yii\db\BaseActiveRecord

    /**
     * Get a relation from the another class relation definition
     * @param ActiveRecord|array|callable|string $target the model class who have relation
     * @param string $relationName relation name in target (case sensitive, without 'get')
     * @return ActiveQuery
     */
    public function hasRelation($target, $relationName){
        $target instanceof ActiveRecord || $target = Yii::createObject($target);
        /** @var ActiveQuery $relationQuery */
        $relationQuery = $target->getRelation($relationName);
        $relationQuery->primaryModel = $this;
        return $relationQuery;
    }

class Order extends ActiveRecord
{
    public function getItems(){
        return $this->hasRelation(OrderItem::className(), 'item')->via('orderItems');
    }
    public function getOrderItems()
    {
        return $this->hasMany(OrderItem::className(), ['order_id' => 'id']);
    }
}

It's avoid double declare link and type of relation (multiple)

Start by reading yii\db\BaseActiveRecord and the relation path involving hasRelation() and via(). Compare the Order and OrderItem example to the current relation declarations, then define how duplicate link and relation-type declarations should be avoided before identifying suitable tests or acceptance criteria.