Preloading HasMany and BelongsTo Associations Causes Infinite Loop Due to Circular Reference

Instead of leading to circular reference or infinite loop, it is recommended to use explicit specification when eager loading necessary relationships, no matter how deep the relationship is. For instance, it may be necessary to remove certain elements. As an alternative solution, when searching for a property, it is best to avoid eager loading all associated images as each image will also eager load the property it belongs to, leading to a repeated process of eager loading all images.


Solution 1:

One way to accomplish this task is by utilizing the

without()

approach, which can be implemented through the use of the following function: https://laravel.com/api/5.8/Illuminate/Database/Eloquent/Builder.html#method_without.

The utilization of

without()

on either end of a connection proved to be effective.

class Property extends EloquentModel {
    protected $with = ['images'];
    public function images()
    {
        return $this->hasMany(Image::class)->without('property');
    }
}

class Image extends EloquentModel {
    protected $with = ['property'];
    public function property()
    {
        return $this->belongsTo(Property::class)->without('images');
    }
    public function getAlt()
    {
        return $this->property->title;
    }
}

UPDATE:

Despite the fact that

without()

can help prevent infinite loops, my extensive knowledge of Laravel has shown me that it is not advisable to include

$with

in the model because it results in loaded relationships that can cause circular references and infinite loops.

It’s better to utilize

with()

for indicating the required eager loading relationships, no matter how deep they are (even if it’s a relationship of a relationship).

For example:

$user = User::with('images' => function ($query) {
            $query->with('property' => function ($query) {
                $query->with('deeperifneeded' => function ($query) {
                    //...
                });
            });
        ]);

It may be necessary to eliminate

without()

.



Solution 2:


While searching for a property, the property itself loads all of its images, and each image in turn loads the property it belongs to. As a result, if you try to find a particular property, it will continue to load all of its images, leading to a cycle of eager loading.

To solve this issue, I suggest avoiding eager loading within the models and instead, perform eager loading at the time of calling the models.

so using the following:

$prop = Property::with('images')->find(203);

Eliminating the aforementioned line from the Property model.

protected $with = ['images'];

And this line in the Image model:

protected $with = ['property'];

I hope this solution works for you.

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