How to remove a parent entity if a child collection is empty? - symfony

Question

I have 2 entities: Game and Product. A Game has a One to Many relationship with Product.
Game is defined as
class Game
{
/**
* #ORM\OneToMany(targetEntity=Product::class, mappedBy="game")
*/
private $products;
}
In order to delete Game when $games->getProducts() is empty, I created an onFlush listener. The issue is that the count of products is the count before the changes are actually applied. This will work fine if I remove entities one by one, but will fail if I remove 2 or more products at once as I cannot confirm that collection is empty, any idea how I could achieve this?
The Listener is defined as such:
class ChainDeletionListener {
public function onFlush(OnFlushEventArgs $event): void {
$em = $event->getEntityManager();
$uow = $em->getUnitOfWork();
foreach ($uow->getScheduledEntityDeletions() as $entity) {
// We check if the deleted entities are Product
if ($entity instanceof Product) {
/** #var Product $entity */
$game = $entity->getGame();
if (sizeof($game->getProducts()) === 1) {
// If the Product we are removing is the last one, we also remove the Game
$em->remove($game);
$uow->computeChangeSet($em->getClassMetadata(get_class($entity)), $entity);
}
}
}
}
}
Thank you for the help!

Answer 1

In your #OneToMany annotation, add "cascade" attribute:
class Game
{
/**
* #ORM\OneToMany(targetEntity=Product::class, mappedBy="game", cascade={"persist", "remove"})
*/
private $products;
}

Answer 2

The simple approach would be to actually load the game entity with its products collection and remove the products in that collection alongside.
class ChainDeletionListener {
public function onFlush(OnFlushEventArgs $event): void {
$em = $event->getEntityManager();
$uow = $em->getUnitOfWork();
foreach ($uow->getScheduledEntityDeletions() as $entity) {
// We check if the deleted entities are Product
if ($entity instanceof Product) {
/** #var Product $entity */
$game = $entity->getGame();
$game->removeProduct($entity); // <-- NEW, might have to implement
if (sizeof($game->getProducts()) === 0) { // <-- NEW changed size: 0
// If the Product we are removing is the last one, we also remove the Game
$em->remove($game);
$uow->computeChangeSet($em->getClassMetadata(get_class($entity)), $entity);
}
}
}
}
}
This assumes a fault-tolerant removal Game::removeProduct(Product) implementation. The obvious downside is the games' collections always being loaded. I don't see a safe way around that.
Alternatively, you could go post-flush and check for games with zero products.