Related factories in a factory definition, will always be created, despite the use of for() method

[kirkbushell]

Laravel Version

PHP Version

Database Driver & Version

n/a

Description

When using model factories, whom also create related factories, if you use the for() method when creating the initial model, it will still create the related factories, meaning you end up with 1+ more relationships for that related factory, which is unintuitive. If the for() method is used OR the field is defined for that relationship, the related factory should not be created.

This ruined me for a couple of days trying to figure out why I had multiple related models being setup when I had specified the relationships that I wanted to create, manually for a given model.

Steps To Reproduce

Setup a model with a relationship. Ensure that relationship is also setup as part of the model's factory. Now, set that relationship manually using the for() method. You'll find that 2 relationships are actually created when the test is run.

[dxnter]

I wasn't able to reproduce this issue with the straightforward case. for() does correctly override the factory in definition():

// PostFactory has: 'user_id' => User::factory()

$user = User::factory()->create();
Post::factory()->for($user)->create();
User::count(); // 1

Where you do get unexpected duplicates is when the model has multiple BelongsTo relationships to the same model type:

// Post has both user_id and reviewer_id pointing to User
class PostFactory extends Factory
{
    public function definition()
    {
        return [
            'user_id' => User::factory(),
            'reviewer_id' => User::factory(),
            'title' => fake()->sentence(),
        ];
    }
}

$user = User::factory()->create();
Post::factory()->for($user)->create();
User::count(); // 2, only overrode user_id. reviewer_id's factory still ran

If this is your situation, recycle() is the fix. It makes all nested factory calls for that model type reuse the provided instance instead of creating new ones:

$user = User::factory()->create();
Post::factory()->recycle($user)->create();
User::count(); // 1