New in Symfony 6.2: Improved Enum Support

Enums as Service Parameters

Contributed by
Aleksey Polyvanyi
in #48045.

In addition to holding service objects, the container also holds configuration, called service parameters. They support all kinds of PHP types (integers, booleans, arrays, strings, constants, etc.) In Symfony 6.2, when using PHP to configure services, you can include Enum values in these parameters:

// config/services.php
namespace Symfony\Component\DependencyInjection\Loader\Configurator;

use App\Entity\BlogPost;

return static function (ContainerConfigurator $container) {
    $container->parameters()
        // ...

        ->set('app.some_parameter', SomeEnum::Foo)
        ->set('app.another_parameter', [SomeEnum::Foo, SomeEnum::Bar]);
};

Enums in YAML Files

Contributed by
Nicolas Grekas
in #46771.

The previous feature only works when defining services in PHP. That's why in Symfony 6.2 we've also added support to reference PHP Enums in YAML files using the special prefix !php/enum.

The previous example looks as follows when using YAML:

# config/services.yaml
parameters:
    # ...
    app.some_parameter:    !php/enum SomeEnum::Foo
    app.another_parameter: [!php/enum SomeEnum::Foo, !php/enum SomeEnum::Bar]

Enums in Environment Variables

Contributed by
Jack Worman
in #46564.

The environment variable processors provided by Symfony transform the env var values (which can only be strings) into other kinds of values needed by your application (booleans, PHP constants, JSON documents, etc.)

In Symfony 6.2 we're adding a new env(enum:...) processor to turn env vars into PHP BackedEnum types. Imagine that you have this enum defined in your project:

# src/Enum/AppEnvironment.php
enum AppEnvironment: string {
   case Dev = 'dev';
   case Prod = 'prod';
   case Stage = 'stage';
   case Test = 'test';
}

In your YAML, XML or PHP configuration, you can now use something like this:

# config/services.yaml
parameters:
    app.some_parameter: '%env(enum:App\Enum\AppEnvironment:APP_ENV)%'

The value stored in the APP_ENV env var would be a string like 'Dev' but the application will use the AppEnvironment::Dev enum value.