Adding new entity Sylius - sylius

Question

I created new entity in App\Entity\, and have this error:
Compile Error: Declaration of App\Entity\OrderItem::getVariant(): ?App\Entity\ProductVariantInterface must be compatible with Sylius\Component\Core\Model\OrderItem::getVariant(): ?Sylius\Component\Core\Model\ProductVariantInterface
This is my OrderItem.php:
<?php
namespace App\Entity;
use App\Entity\Constants\DeliveryLocationConstants;
use Sylius\Component\Core\Model\OrderItem as BaseOrderItem;
use Doctrine\ORM\Mapping as ORM;
use App\Entity\OrderItemInterface as BaseOrderItemInterface;
/**
* #ORM\Entity()
* #ORM\Table(name="sylius_order_item")
*
* Class OrderItem
* #package App\Entity
*/
class OrderItem extends BaseOrderItem implements BaseOrderItemInterface
{
/** #var ProductVariantInterface */
protected $variant;
/** #var string */
protected $productName;
/** #var string */
protected $variantName;
/** #var string */
protected $optiune;
/**
* {#inheritdoc}
*/
public function getVariant(): ?ProductVariantInterface
{
return $this->variant;
}
/**
* {#inheritdoc}
*/
public function setVariant(?ProductVariantInterface $variant): void
{
$this->variant = $variant;
}
public function getProduct(): ?ProductInterface
{
return $this->variant->getProduct();
}
/**
* {#inheritdoc}
*/
public function getProductName(): ?string
{
return $this->productName ?: $this->variant->getProduct()->getName();
}
/**
* {#inheritdoc}
*/
public function getOptiune(): ?string
{
return $this->optiune;
}
/**
* {#inheritdoc}
*/
public function setOptiune(?string $optiune): void
{
$this->optiune = $optiune;
}
/**
* {#inheritdoc}
*/
public function setProductName(?string $productName): void
{
$this->productName = $productName;
}
/**
* {#inheritdoc}
*/
public function getVariantName(): ?string
{
return $this->variantName ?: $this->variant->getName();
}
/**
* {#inheritdoc}
*/
public function setVariantName(?string $variantName): void
{
$this->variantName = $variantName;
}
/**
* {#inheritdoc}
*/
public function equals(BaseOrderItemInterface $item): bool
{
return parent::equals($item) || ($item instanceof static && $item->getVariant() === $this->variant);
}
/**
* Returns sum of neutral and non neutral tax adjustments on order item and total tax of units.
*
* {#inheritdoc}
*/
public function getTaxTotal(): int
{
$taxTotal = 0;
foreach ($this->getAdjustments(AdjustmentInterface::TAX_ADJUSTMENT) as $taxAdjustment) {
$taxTotal += $taxAdjustment->getAmount();
}
foreach ($this->units as $unit) {
$taxTotal += $unit->getTaxTotal();
}
return $taxTotal;
}
/**
* Returns single unit price lowered by order unit promotions (each unit must have the same unit promotion discount)
*
* {#inheritdoc}
*/
public function getDiscountedUnitPrice(): int
{
if ($this->units->isEmpty()) {
return $this->unitPrice;
}
return
$this->unitPrice +
$this->units->first()->getAdjustmentsTotal(AdjustmentInterface::ORDER_UNIT_PROMOTION_ADJUSTMENT)
;
}
/**
* {#inheritdoc}
*/
public function getSubtotal(): int
{
return $this->getDiscountedUnitPrice() * $this->quantity;
}
}

Answer 1

Error message is pretty clear. You must to redefine getVariant() method like this:
public function getVariant(): ?\Sylius\Component\Core\Model\ProductVariantInterface
{
return $this->variant;
}
because in PHP parent class BaseOrderItem persist you to return Core\Model\ProductVariantInterface in this method