eloquent - Laravel Eager loading of a relationship bettween two models causes a relationship between other models return wrong results

Question

I have two Eloquent models named Question and Answer with one to many relationship between them (one question has many answers). The hasMany relationship in Question.php is called answers.

I also have a User and a Company model with a many to many relationship between them which uses a pivot model, defined this way:

User.php

public function companies()
{
    return $this->belongsToMany(Company::class)
        ->using(CompanyUser::class);
}

Company.php

public function users()
{
    return $this->belongsToMany(User::class)
        ->using(CompanyUser::class);
}

When I retreive a question and lazy load its answers:

Question::find(58)->answers;

Everything is okay. The problem comes when I use eager loading:

Question::with('answers')->get();

Something strange happens. In the answers() relationship method of the Question model, I need to get the current user's first company in order to modify the relationship:

auth()->user()->companies->first();

Most of the users in my application have one company attaches to them, when using eager loading though auth()->user()->companies returns not one, but 134 companies even though in the database I have only 5 companies and the current user belongs to only one. When I dumped the contents of the auth()->user()->companies collection I saw that the first company model is exists 130 times and the other 4 companies are also included.

This happens only in the answers() method and only when using eager loading. Any ideas why?

Environment:

• Laravel version: 6.20.6
• PHP version: 8.0.1
• Apache: 2.4.26
• DB: 10.1.27-MariaDB

question from:https://stackoverflow.com/questions/65869706/laravel-eager-loading-of-a-relationship-bettween-two-models-causes-a-relationshi

Answer 1

I think you need to get more information on the problem. What I normally do is insert ddd() and check the queries tab to see what queries Laravel is using to get the data. This might shed some more light on the problem.