Symfony version(s) affected

6.2.x

Description

Using the MessageSubscriberInterface it was possible to declare multiple handlers pointing to different methods of a class, without the implementation of those methods being directly defined in that class — e.g.:

class FooHandler 
    extends AbstractHandler // <- contains implementations
    implements MessageSubscriberInterface
{
    public function getHandledMessages(): iterable
    {
        yield SomeMessage::class => ['method' => 'someMethodFromAbstractParent'];
        yield SomeOtherMessage::class => ['method' => 'someOtherMethodFromAbstractParent'];
    }
}

Unless I'm missing something obvious this is no longer possible, as #[AsMessageHandler] would have to be repeatable on the class itself to replicate this functionality, but the attribute lacks the IS_REPEATABLE flag.

Possible Solution

Add the \Attribute::IS_REPEATABLE flag to the existing flags on the attribute, supporting the following syntax:

#[AsMessageHandler(
    handles: SomeMessage::class,
    method: 'someMethodFromAbstractParent',
    priority: 10,
)]
#[AsMessageHandler(
    handles: SomeOtherMessage::class,
    method: 'someOtherMethodFromAbstractParent',
    priority: 10,
)]
class FooHandler 
    extends AbstractHandler // <- contains implementations
{
}

This seems to resolve the issue, and I'm happy to submit a PR if it would be accepted.