Need help implementing createOrFirst logic in Laravel Query Builder to prevent race conditions

[mohammadrasoulasghari]

I’m working on a PR that requires implementing functionality similar to Eloquent’s createOrFirst() method, but using Laravel’s Query Builder instead.

In my PR, Mr Otwell commented: “It’s a bit more atomic to follow createOrFirst logic so there isn’t a race condition.”

After investigating, I couldn’t find any built-in Query Builder method that provides the same atomic operation as Eloquent’s createOrFirst(). While Eloquent has this functionality built-in to handle unique constraints safely, I’m not sure if there’s an equivalent in Query Builder or if I need to implement this logic myself.

My question is:
Is there any built-in infrastructure in Query Builder for handling unique constraints similar to Eloquent’s createOrFirst() method? Or do I need to implement this functionality myself? If I need to implement it, what’s the best approach to ensure atomicity and prevent race conditions?

Here’s the PR I’m working on: [Link to PR

I would be grateful if anyone could guide me on how to implement it.🙏]

[macropay-solutions]

Update

    /**
     * Attempt to create the record. If a unique constraint violation occurs, attempt to find the matching record.
     *
     * @param  array  $attributes
     * @param  array  $values
     * @return \Illuminate\Database\Eloquent\Model|static
     */
    public function createOrFirst(array $attributes = [], array $values = [])
    {
        try {
            return $this->withSavepointIfNeeded(fn () => $this->create(array_merge($attributes, $values)));
        } catch (UniqueConstraintViolationException $e) {
            return $this->useWritePdo()->where($attributes)->first() ?? throw $e;
        }
    }

The logic is not in Eloquent or query builder but:

See \Illuminate\Database\MySqlConnection::isUniqueConstraintError

    protected function isUniqueConstraintError(Exception $exception)
    {
        return boolval(preg_match('#Integrity constraint violation: 1062#i', $exception->getMessage()));
    }

and \Illuminate\Database\Connection::runQueryCallback

We implemented the duplicate check like this:

https://github.com/macropay-solutions/laravel-crud-wizard-free/blob/8dae9487df5f123f74e79c71267c61acfa9e4089/src/Helpers/GeneralHelper.php#L24