New in Symfony 6.2: Improved Enum Support


Symfony introduced PHP enums support in Symfony 5.4, which was released on
November 2021. In Symfony 6.2 we continued adding Enums supports in different
parts of the code.

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 Development = 'dev';
case Production = 'prod';
case Staging = 'stage';
case Testing = '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::Development enum value.

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