Why in children array the parent property does not serialize? - php

Question

I have an issue with serializing data in Symfony/ApiPlatform. For example I have such entity:
<?php
namespace App\Entity;
....
....
#[ApiResource(
normalizationContext: ['groups' => ['read']]
)]
class Test
{
#[ORM\Id]
#[ORM\GeneratedValue]
#[ORM\Column]
private ?int $id = null;
#[Groups('read')]
#[ORM\ManyToOne(targetEntity: self::class, inversedBy: 'children')]
private ?self $parent = null;
#[Groups('read')]
#[ORM\OneToMany(mappedBy: 'parent', targetEntity: self::class)]
private Collection $children;
#[Groups('read')]
#[ORM\Column(length: 255)]
private ?string $title = null;
....
....
}
That is, basically this entity has the parent property and the children property. Each entity can have an ancestor and that ancestor can have another ancestor and so on (max depth=3 I think). And each entity can have children that have children as well and so on, AND each children can have an ancestor.
I created some records in db for this test
When I try to get a collection via GET endpoint I get JSON with such data:
{
....
"hydra:member": [
{
"#id": "/api/tests/1",
"#type": "Test",
"children": [
{
"#id": "/api/tests/2",
"#type": "Test",
"parent": "/api/tests/1",
"children": [
{
"#id": "/api/tests/3",
"#type": "Test",
"parent": "/api/tests/2",
"children": [],
"title": "test3"
}
],
"title": "test2"
}
],
"title": "test1"
},
{
"#id": "/api/tests/2",
"#type": "Test",
"parent": {
"#id": "/api/tests/1",
"#type": "Test",
"children": [
"/api/tests/2"
],
"title": "test1"
},
"children": [
{
"#id": "/api/tests/3",
"#type": "Test",
"parent": "/api/tests/2",
"children": [],
"title": "test3"
}
],
"title": "test2"
},
{
"#id": "/api/tests/3",
"#type": "Test",
"parent": {
"#id": "/api/tests/2",
"#type": "Test",
"parent": {
"#id": "/api/tests/1",
"#type": "Test",
"children": [
"/api/tests/2"
],
"title": "test1"
},
"children": [
"/api/tests/3"
],
"title": "test2"
},
"children": [],
"title": "test3"
}
],
....
}
As you can see each item has parent and children, it's okey. But if we'll look at children then we'll see the parent property and this property is in IRI format. This is my issue. It should be like object
I've already tried to any groups for this. Alse I've tried to add #MaxDepth to each property, for instance:
#[MaxDepth(5)]
#[Groups('read')]
#[ORM\OneToMany(mappedBy: 'parent', targetEntity: self::class)]
private Collection $children;
#[MaxDepth(5)]
#[Groups('read')]
#[ORM\Column(length: 255)]
private ?string $title = null;
And also I enabled max_depth
#[ApiResource(
normalizationContext: [
'enable_max_depth' => 'true',
'groups' => ['read']
]
)]
but It didn't work. I've tried to write custom normalizer but without success.
I expected that in each 'children' property will be 'parent' property like object instead of IRI string. How to solve it?