FAQ

Where should I start if I am completely new to this package?

Start with Quickstart. It introduces the package with one ArrayServiceProvider and one call to container() . That is the smallest setup that still reflects how the package is meant to be used in real projects.

Do I have to register every class manually?

No. You usually register only the parts that need runtime configuration or special construction logic. The final container is autowire-enabled, so classes whose constructor dependencies are already known by type can often be created automatically.

When should I use a provider instead of an existing PSR-11 container?

Use a provider when you want to declare services in package or application code. Use an existing PSR-11 container when another framework or subsystem already owns those services and you want FastForward Container to compose with it instead of replacing it.

Why do config values use config.* but provider registration uses ContainerInterface::class ?

The raw configuration object and the container view are different layers.

• In the raw config object, nested providers are stored under FastForward\Container\ContainerInterface::class .
• Once the config is wrapped by ConfigContainer , normal config values are exposed through service IDs such as config.app.name .

This is why you do not store raw values under config.* keys yourself.

Why does CallableFactory throw an exception when my closure expects a string?

CallableFactory resolves parameters by class or interface type. Builtin types such as string , int , and array are not container-resolvable in that factory, so it throws RuntimeException . If you need scalar values, use InvokableFactory , ServiceFactory , or a callable that reads those values from another typed service.

How do I expose the same service under two IDs?

Use AliasFactory when both IDs should resolve to the same object. If you already created the object yourself and want multiple IDs, you can also register the same instance through ServiceFactory in more than one place, but AliasFactory usually keeps the intent clearer.

How do I decorate a service after it is created?

Add an extension in your provider. Extensions receive the container and the previously created service instance, which lets you attach collaborators, runtime options, or cross-cutting behavior after construction.

How do collisions work when multiple providers define the same ID?

It depends on how you combine them:

• container($providerA, $providerB) : the first matching provider wins
• new AggregateServiceProvider($providerA, $providerB) : later factory keys overwrite earlier ones

This difference is intentional, so choose the model that matches your override strategy.

Can I resolve the container itself from inside a factory?

Yes. AggregateContainer registers itself under several aliases, including container , FastForward\Container\ContainerInterface , and Psr\Container\ContainerInterface .

When should I use prepend() or append() on AggregateContainer ?

Use prepend() when you want a new container to override existing registrations. Use append() when you want a fallback container that is only consulted after the current resolution chain is exhausted.

Why does AutowireContainer::has() sometimes return false even when a delegate says true ?

AutowireContainer performs a stricter check than a plain delegated has() call. It tries to resolve the service and returns false if construction throws. This avoids reporting a service as available when it is declared but not actually buildable.

What is the safest beginner-friendly default for a new project?

Start with one ArrayServiceProvider , build the container through container($provider) , register scalar configuration explicitly, and allow autowiring to fill in the rest. This approach keeps the learning curve low while still matching the package's long-term design.