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Two-phase commit

This case explores a race condition where a Product is being renamed, but between the check for the name and the persist another Product with the same name is inserted. In such case we want to rollback the renaming.

use Formal\ORM\Id;
use Innmind\Specification\{
    Comparator\Property,
    Sign,
};

$repository = $orm->repository(Product::class);
$hasNewName = Property::of(
    'name',
    Sign::equality,
    'New name',
);
$productWithOldName = $orm->transactional(
    static fn() => $repository
        ->get(Id::of(Product::class, 'some-uuid'))
        ->filter(static fn() => $repository->none($hasNewName))
        ->flatMap(
            static fn($product) => $repository
                ->put($product->rename('New name'))
                ->map(static fn() => $product)
                ->maybe(),
        )
        ->either(),
)->match(
    static fn($product) => $product,
    static fn() => throw new \Exception('Product does not exist, could not be persisted or name already used'),
);

if ($repository->size($hasNewName) === 1) {
    // no other product has been inserted with the same name
    return;
}

$orm->transactional(
    static fn() => $repository
        ->put($productWithOldName)
        ->either(),
);

final readonly class Product
{
    /**
     * @param Id<self> $id
     */
    public function __construct(
        private Id $id,
        private string $name,
    ) {
    }

    public function rename(string $name): self
    {
        return new self($this->id, $name);
    }
}

Because aggregates are immutable, rollbacking one to an old state is as simple as persisting the original object fetched from the storage.