How valid is a condition on a relation in laravel?

Question

Laravel

Good afternoon,
There are 2 models - User and Contract( provider_id, customer_id, sign )

class User extends Model {
    public function isProvider()
    {
        return $this->role === 1;
    }

    public function isCustomer()
    {
        return $this->role === 2;
    }

   public function contracts()
    {
        if($this->isProvider())
            return $this->hasMany(Contract::class, 'provider_id');
        if($this->isCustomer())
            return $this->hasMany(Contract::class, 'customer_id');
    }

}

How correct is the implementation of the contracts relationship ?
Does it make sense to inherit Provider and Customer from User and write relationships in them?

Answer 1

Laravel does not care deeply, this is business logic. The problem can only be in the opposite direction if the user is tied to the contract:

// что за юзер — провайдер или потребитель?
// по какому полю строить связь?
$contract->user()->associate($user);

However, apparently, it is enough to make a similar construction with conditions on the other side. But there may be problems: they created an instance of the model, provider_idand customer_iddid not fill it in - what to check in the conditions?