Unable to use Interface with CakePHP Dependency Injection - "Argument must be of type AuthorizationServiceInterface, string given"

Question

I want to create a service class in my app that has the AuthorizationService as a dependency so it can access the user’s identity. I have this constructor:

public function __construct(
    private readonly AuthorizationServiceInterface $authorization,
    private readonly OrganizationsTable $organizationsTable,
    private readonly array $config = []
) { ... }

I have an AuthorizationServiceProvider that I’ve registered in Application::services() but it actually does two jobs:

1. extends ServiceProvider and implements services()
2. implements AuthorizationServiceProviderInterface and implements getAuthorizationService()

(Technically the book says to attach the latter interface to your Application class but I broke it out into a separate class and I instantiate that class and pass it to the AuthorizationMiddleware. This part works fine.)

For my services method in this class I have:

public function services(ContainerInterface $container): void
{
    $container->add(AuthorizationServiceInterface::class, function () use ($container) {
        $request = $container->get(ServerRequestInterface::class);
        return $this->getAuthorizationService($request);
    });
}

So basically I’m trying to register the AuthorizationServiceInterface in the container then provide a concrete implementation by calling my getAuthorizationService() method in this same class.

Crucially, in this class I also have:

protected $provides = [
    AuthorizationServiceInterface::class,
];

However, I’m getting this error:

“App\\Service\\Crud\\Organization\\OrganizationSearcher::__construct(): Argument #1 ($authorization) must be of type Authorization\\AuthorizationServiceInterface, string given” 

In the past this has always indicated (to me) that I’m missing that class FQCN in the $provides class property. But as you can see, it is there.

What am I doing wrong?

1. Tried ensuring the AuthorizationServiceInterface was present in the $provides class property
2. Tried clearing the cache with bin/cake cache clear_all
3. Tried reordering the Service Providers in Application::services() to see if that had any effect

Ultimately, I expect the service container to be able to resolve an AuthorizationServiceInterface by using my getAuthorizationService() method and pass it to my service class that needs it.