Faker unique() causes an error

[Fukao0129]

Laravel Version

11.26.0

PHP Version

8.3.14

Database Driver & Version

8.0.36 - MySQL Community Server - GPL

Description

The seeder fails when fake()->unique() is used in a factory.

Error message:
Maximum retries of 10000 reached without finding a unique value

I'm creating 50 records:
factory()->count(50)->create()

And generating unique numbers between 1 and 50:
fake()->unique()->numberBetween(1, 50)

So unique numbers cannot be exhausted.

According to this issue, I can use fake()->unique(true).
This will eliminate errors, but it will cause data to become non-unique and duplicates to be generated.

Steps To Reproduce

1. Create a migration
2. Create a seeder

namespace Database\Seeders;

use Illuminate\Database\Seeder;
use App\Models\Example;

class ExampleTableSeeder extends Seeder
{
    public function run()
    {
        Example::factory()->count(50)->create();
    }
}

3. Create a factory

namespace Database\Factories;

use Illuminate\Database\Eloquent\Factories\Factory;

class ExampleFactory extends Factory
{
    public function definition(): array
    {
        return [
            'please_be_unique' => fake()->unique()->numberBetween(1, 50),
        ];
    }
}

4. Do migrate:fresh --seed

[timacdonald]

It is possible to generate 10,000 random numbers between 1 and 50 and not successfully generate all unique numbers from 1-50.

It could, for example, never randomly generate the number 42. Even after 10,000 attempts.

You may need to keep a static variable of values and pop them off randomly instead.

[Fukao0129]

@timacdonald
I'm very grateful for your quick reply!
I'm sorry if there are any elementary misunderstandings about unique() method.

I'm creating 50 records:
factory()->count(50)->create()

And unique() is used for the same column in each factory.
In this case, each of the 50 values in that column will be unique.
Is it right so far?

I believe that 50 executions of fake()->unique()->numberBetween(1, 50) will create 50 records, and the numbers from 1 to 50 will each be entered into 50 records in random order.

Is this the wrong way to use it?