Doctrine OneToMany relation does not fetch related entities - symfony

Question

I am stuck at this case, I reproduced it in an example from symfony documentation, here it how it looks:
FIXTURES
/**
* #ORM\Entity
*/
class Category
{
/**
* #ORM\Id
* #ORM\Column(type="integer")
* #ORM\GeneratedValue
*/
private $id;
/**
* #ORM\OneToMany(targetEntity="Product", mappedBy="category", fetch="EAGER")
*/
private $products;
public function __construct()
{
$this->products = new ArrayCollection();
}
public function products(): Collection
{
return $this->products;
}
public function id()
{
return $this->id;
}
}
and related Product class
/**
* #ORM\Entity
*/
class Product
{
/**
* #ORM\Id
* #ORM\Column(type="integer")
* #ORM\GeneratedValue
*/
protected $id;
/**
* #ORM\ManyToOne(targetEntity="Category", inversedBy="products")
* #ORM\JoinColumn(name="category_id", referencedColumnName="id")
*/
private $category;
public function __construct($category)
{
$this->category = $category;
}
public function id()
{
return $this->id;
}
public function category()
{
return $this->category;
}
}
TEST
Now I have this snippet of test code where I want to fetch Category and be able to get its Products:
$cat = new Category();
$prod = new Product($cat);
$this->entityManager->persist($prod);
$this->entityManager->persist($cat);
$this->entityManager->flush();
$crepo = $this->getEntityManager()->getRepository(Category::class);
$c = $crepo->findAll()[0];
var_dump(get_class($c->products()), $c->products()->count())
What I am getting is products of class PersistentCollection which is expected, but the count is 0 while there should be 1 product.
I can see that in the database I have proper category and product records with proper foreign key set.
WORKAROUND
I am debugging PersistentCollection for products and can see that its flag is set to initialized = true. With this I am able to force this to work by calling
$c->products()->setInitialized(false);
$c->products()->initialize();
But afaik this is not how it should work, should it ?

Answer 1

I managed to found an answer. It basically works but not when run in the same process. If I split the script in two - first one persists, second retrieves the data then the products collection will contain products related to category.
This is because when it is done in single process doctrine does not know that the category in question has products, and since it retrieves the same object it just saved and that was created few lines above, the entity manager won't populate the collection using database but will use the one from the category object. And the category object does not have products in products collection, since there is no call like $this->products()->add($category) neither in Product constructor or anywhere else. Only forcing to reinitialize the collection works since then it really retrieves products from database