Sylius/adr/2024_10_03_services_naming_convention.md

Services naming convention

• Status: Accepted
• Date: 2024-02-24

Context and Problem Statement

Services in Sylius are named in different ways, depending on the time of their creation, and other services' names. Also, some services named with using the dot notation are harder to be used with autowire feature.

Decision Drivers

• Make naming services predictable
• Provide a consistent way of naming services
• Support the autowire feature

Considered Options

Stay with the dot notation

This variant is the most common way of naming services in Sylius from the beginning. It was the only considered option in Symfony-based projects before the autowire feature was introduced.

• Good, because it is a common way of naming services in Symfony
• Bad, because you have to use #[Autowire] attribute to inject services

Use the FQCN as a service name

This variant of naming appeared along with introducing the autowire feature in Symfony. It makes using services easier, but at the same time introduces a little bit magic to the code.

• Good, because it supports the autowire feature
• Bad, because it requires a lot of work from the developers already using the dot notation
• Bad, because it is not recommended by Symfony

Combine the dot notation with the FQCN (when it makes sense)

This variant is a combination of the previous two options, but it considers declaring the FQCN alias only when it makes sense.

• Good, because it is a recommended way by Symfony Best Practices for Reusable Bundles
• Good, because we use the dot notation for many services, so we do not have to rename them
• Good, because services already named with the FQCN will still work
• Bad, because it requires more work and increases the number of service definitions

Decision Outcome

Chosen option: "Combine the dot notation with the FQCN (when it makes sense)"

Despite the fact that it requires more work, it is the best option to provide a consistent way of naming services and support the autowire feature. Also, thanks to this approach, we stay consistent with the Symfony best practices.

Some services that are not meant to be used with the autowire feature should only be named with the dot notation:

• form types/extensions
• message handlers
• validators
• etc.

Example

The simplest case is when we have 1:1 relation between the interface and the implementation:

<services>
    <service id="sylius_admin.resolver.some" class="Sylius\Bundle\AdminBundle\Resolver\SomeResolver" />
    <service id="Sylius\Bundle\AdminBundle\Resolver\ResolverInterface" alias="sylius_admin.resolver.some" />
</services>

If there are multiple services implementing the same interface:

<services>
    <service id="sylius_admin.resolver.some" class="Sylius\Bundle\AdminBundle\Resolver\SomeResolver" />
    <service id="sylius_admin.resolver.another" class="Sylius\Bundle\AdminBundle\Resolver\AnotherResolver" />
    <service id="Sylius\Bundle\AdminBundle\Resolver\ResolverInterface" alias="sylius_admin.resolver.some" /> <!-- default when the parameter name is different from belows -->
    <service id="Sylius\Bundle\AdminBundle\Resolver\ResolverInterface $someResolver" alias="sylius_admin.resolver.some" /> <!-- added just in case the default one changes -->
    <service id="Sylius\Bundle\AdminBundle\Resolver\ResolverInterface $anotherResolver" alias="sylius_admin.resolver.another" />
</services>

References

• Best Practices for Reusable Bundles