Duplicate ressources in ManyToMany relations

[guilhemVB]

Hi,

I've a problem with serialization groups and ManyToMany relations in sub ressoucres.
I've a Entity "Order" with one attribute CustomerBy (ManyToOne to entity "Customer") and one attribute CustomerFor (ManyToOne to entity "Customer" too).
Customer have an attribute addresses (ManyToMany to entity Address)

When Order have the same Customer in "CustomerBy " and "CustomerFor", all the addresses are duplicated:

Order:

<?php

namespace App\Entity;

use ApiPlatform\Core\Annotation\ApiResource;
use Doctrine\ORM\Mapping as ORM;
use Symfony\Component\Serializer\Annotation\Groups;
use Symfony\Component\Validator\Constraints as Assert; 

/**
 * @ApiResource(
 *     attributes={"normalization_context"={"groups"={"order_read", "customer_read", "address_read"}}}
 * )
 * @ORM\Entity
 * @ORM\Table(name="`order`")
 */
class Order
{

    /**
     * @var integer
     *
     * @ORM\Id
     * @ORM\Column(type="integer")
     * @ORM\GeneratedValue(strategy="AUTO")
     * @Groups({"order_read"})
     */
    private $id;
    
    /**
     * @ORM\ManyToOne(targetEntity="Customer")
     * @ORM\JoinColumn(nullable=false)
     * @Groups({"order_read"})
     */
    public $customerBy;
    
    /**
     * @ORM\ManyToOne(targetEntity="Customer")
     * @ORM\JoinColumn(nullable=false)
     * @Assert\NotNull()
     * @Groups({"order_read"})
     */
    public $customerFor;

    public function getId()
    {
        return $this->id;
    }
}

Customer:

<?php

namespace App\Entity;

use ApiPlatform\Core\Annotation\ApiResource;
use Doctrine\Common\Collections\ArrayCollection;
use Doctrine\ORM\Mapping as ORM;
use Symfony\Component\Serializer\Annotation\Groups;

/**
 * @ApiResource(
 *     attributes={"normalization_context"={"groups"={"customer_read"}}}
 * )
 * @ORM\Entity
 */
class Customer
{

    /**
     * @var integer
     *
     * @ORM\Id
     * @ORM\Column(type="integer")
     * @ORM\GeneratedValue(strategy="AUTO")
     * @Groups({"customer_read"})
     */
    private $id;

    /**
     * @ORM\Column(type="string")
     * @Groups({"customer_read"})
     */
    public $name;
    
    /**
     * @ORM\ManyToMany(targetEntity="Address")
     * @ORM\JoinColumn(nullable=false)
     * @Groups({"customer_read"})
     */
    public $addresses;

    public function __construct()
    {
        $this->addresses = new ArrayCollection();
    }

    public function getId()
    {
        return $this->id;
    }
}

Address:

<?php

namespace App\Entity;

use ApiPlatform\Core\Annotation\ApiResource;
use Doctrine\ORM\Mapping as ORM;
use Symfony\Component\Serializer\Annotation\Groups;

/**
 * @ApiResource(
 *     attributes={"normalization_context"={"groups"={"address_read"}}}
 * )
 * @ORM\Entity
 */
class Address
{

    /**
     * @var integer
     *
     * @ORM\Id
     * @ORM\Column(type="integer")
     * @ORM\GeneratedValue(strategy="AUTO")
     * @Groups({"address_read"})
     */
    private $id;
    
    /**
     * @ORM\Column(type="string")
     * @Groups({"address_read"})
     */
    public $name;


    public function getId()
    {
        return $this->id;
    }
}

When I send a GET request to /api/orders/1 I've the following result:

{
  "id": 1,
  "customerBy": {
    "id": 1,
    "name": "Customer 1",
    "addresses": [
      {
        "id": 1,
        "name": "Address 1"
      },
      {
        "id": 1,
        "name": "Address 1"
      },
      {
        "id": 2,
        "name": "Address 2"
      },
      {
        "id": 2,
        "name": "Address 2"
      }
    ]
  },
  "customerFor": {
    "id": 1,
    "name": "Customer 1",
    "addresses": [
      {
        "id": 1,
        "name": "Address 1"
      },
      {
        "id": 1,
        "name": "Address 1"
      },
      {
        "id": 2,
        "name": "Address 2"
      },
      {
        "id": 2,
        "name": "Address 2"
      }
    ]
  }
}

You can see that all "addresses" are duplicated :/

Did I miss something or is it a bug ?

My Api-platform version:

"name": "api-platform/core",
"version": "v2.3.0"

Thanks

[ilicmsreten]

@guilhemVB I open PR in api-platform/core

[soyuka]

todo before closing: Add a behat test in api-platform/core for this particular behavior

[ilicmsreten]

@soyuka I open PR

[errogaht]

Hi guys! I got the same issue, do you have an idea how we can fix it?

[soyuka]

solution is to simply disable the eager loading feature or build your own query. I'm really not sure how we could fix this otherwise...

For the #799 example:

/**
 * @ApiResource(
 *     attributes={"normalization_context"={"groups"={"order_read", "customer_read", "address_read"}}, "force_eager"=false}
 * )
 * @ORM\Entity
 * @ORM\Table(name="`order`")
 */
class Order
{
}

[errogaht]

@soyuka, if I'll set "force_eager"=false is there could be some side-effects? eg. filters will not work correctly or pagination or something else?

[soyuka]

Everything will work, this just skips the magic in building queries based on what you want to retrieve. Basically EagerLoading in api platform builds the sql query with JOINs where it can. By disabling it you'll keep the default doctrine behavior which, in this case, is more appropriate (lazy loading).

[errogaht]

@soyuka , thanks, I'll disable force_eager system-wide in api-platform configuration. should be fine I believe.

[soyuka]

You can also disable it per-operation or per-resource wise see https://api-platform.com/docs/core/performance/#force-eager