Set generic type

[pimjansen]

Hey,

This is my actually error and no idea how to fix this:

  31     Method Acme\Communication\Email\Infrastructure\Write\EmailRepositoryEventSauce::retrieve() should return T  
         of Acme\Communication\Email\Domain\Email but returns EventSauce\EventSourcing\AggregateRoot. 

This is the actual code:

class EmailRepositoryEventSauce implements EmailRepository
{
    public function __construct(private AggregateRootRepository $repository)
    {
    }

    public function persist(Email $email): void
    {
        $this->repository->persist($email);
    }

    public function retrieve(string $communicationId): Email
    {
        return $this->repository->retrieve(CommunicationId::fromString($communicationId));
    }
}

And as you can see here, the error makes sense however the expected Email class actually implements that Interface

final class Email implements AggregateRoot
{

[ondrejmirtes]

Please reproduce that on phpstan.org/try.

[ondrejmirtes]

are coming from a vendor package

Which is fine, you can override 3rd party PHPDocs with stub files: https://phpstan.org/user-guide/stub-files

So the error you're trying to solve:

Parameter #1 $id of class EmailWasBounced constructor expects CommunicationId, AggregateRootId given.

AggregateRootId isn't CommunicationId so this error is expected. The classes involved are already ready for generics so you just need to tell them what's going on (as the other two errors are trying to tell you): https://phpstan.org/r/4b2d0153-b349-4603-8a31-b3a1587970c3

[ondrejmirtes]

Here are some materials on generics:

• https://phpstan.org/blog/generics-in-php-using-phpdocs
• https://phpstan.org/blog/generics-by-examples
• https://phpstan.org/blog/whats-up-with-template-covariant
• https://phpstan.org/blog/guide-to-call-site-generic-variance

[pimjansen]

Im just gonna ask for one more thing since im still a bit stuck on this (generic part). How can i solve this last error?

https://phpstan.org/r/758df9d3-9e0e-4a4e-8ebd-2f4d73346d91
Method EmailRepositoryEventSauce::retrieve() should return Email but returns AggregateRoot.

I tried setting the @implements EmailRepository on it but that doesnt do the trick so im a bit lost on how to override this though

[ondrejmirtes]

That would be done by /** @param AggregateRootRepository<...> $repository */ above the constructor, but you want to return Email, but class Email isn't AggregateRoot so I'm not sure how you want to set up the types there.

[pimjansen]

That would be done by /** @param AggregateRootRepository<...> $repository */ above the constructor, but you want to return Email, but class Email isn't AggregateRoot so I'm not sure how you want to set up the types there.

Let me check! I think email is implementing AggregateRoot but i left out some stuff since it was full of implementation specifics