[BUG] hasMany and hasOne relation not working with ObjectId

[florianJacques]

Hello
The _id autocast is a problem on HasOne and HasMany relations, as it prevents comparisons with ObjectId

public function getIdAttribute($value = null)
{
    // If we don't have a value for 'id', we will use the MongoDB '_id' value.
    // This allows us to work with models in a more sql-like way.
    if (! $value && array_key_exists('_id', $this->attributes)) {
        $value = $this->attributes['_id'];
    }

    // Convert ObjectID to string.
    if ($value instanceof ObjectID) {
        return (string) $value;
    }

    if ($value instanceof Binary) {
        return (string) $value->getData();
    }

    return $value;
}

Indeed, this relationship always returns me null

public function accessToken(): HasOne
{
    return $this->hasOne(AccessToken::class, 'userId', '_id');
}

But if I remove the line

// Convert ObjectID to string.
if ($value instanceof ObjectID) {
    return (string) $value;
}

The relation working

[florianJacques]

I propose this solution to get around the problem without breaking the existing system.
What do you think?

protected bool $castKey = true;

public function getIdAttribute($value = null): mixed
{
    return $this->castKey ? parent::getIdAttribute($value) : $value;
}

public function accessTokens(): HasMany
  {
      $this->castKey = false;
      $hasMany =  $this->hasMany(AccessToken::class, 'userId', '_id');
      $this->castKey = true;

      return $hasMany;
  }

Unfortunately does not work with method....

I don't know why you put a default attribute mutator on the id, I wonder if it shouldn't be removed.

[masterbater]

#2753 (comment)

I have a simple replication for this issue

[tarranjones]

The only way I've found to stop _id from auto casting is to capture it before mutateAttribute strips the leading underscore.
By the time getIdAttribute is called we do not know which property was called id or _id.

The following patch will return a string for $mode->id and a ObjectID for $model->_id.
This fixes the hasOne hasMany issues without needing to specify additional parameters.

is_string($model->id); // true
$model->_id instanceof ObjectId; // true

<?php

declare(strict_types=1);

namespace App\MongoDB\Eloquent;

use MongoDB\BSON\ObjectId;
use MongoDB\Laravel\Eloquent\Model;

/**
 * Trait IdAttributePatch
 * @link https://github.com/mongodb/laravel-mongodb/issues/2753
 * @link https://github.com/mongodb/laravel-mongodb/issues/2788
 * @mixin Model
 * @property ObjectId $_id
 * @property string $id
 */
trait IdAttributePatch
{
    /**
     * Determine if a get mutator exists for an attribute.
     *
     * @param  string  $key
     * @return bool
     */
    public function hasGetMutator($key): bool
    {
        return $key === '_id' || parent::hasGetMutator($key);
    }

    /**
     * Get the value of an attribute using its mutator.
     *
     * @param  string  $key
     * @param  mixed  $value
     * @return mixed
     */
    protected function mutateAttribute($key, $value): mixed
    {
        if ($key === '_id') {
            // replicate getIdAttribute but without the (string) casting
            return $value ?: ($this->attributes['_id'] ?? $value);
        }
        return parent::mutateAttribute($key, $value);
    }

    public function getQueueableId(): string
    {
        return (string) parent::getKey();
    }
}
`