Add service migrations (POC)

[HypeMC]

Inspired by #521 (comment)

This is a proposed implementation for registering migrations as services.

To get this working Symfony needs to be able to autoload migrations:

    "autoload": {
        "psr-4": {
            "App\\": "src/",
            "DoctrineMigrations\\": "migrations/"
        }
    },

Then, import the migrations as services:

    DoctrineMigrations\:
        resource: '../migrations/'

Of course, an alternative approach would be to move the migrations folder to src and change the namespace to App\Migrations.

Once that is done, all you need to do is override the constructor and inject the desired services.

final class Version20240121015756 extends AbstractMigration
{
    public function __construct(
        Connection              $connection,
        LoggerInterface         $logger,
        private RouterInterface $router,
    ) {
        parent::__construct($connection, $logger);
    }

    public function up(Schema $schema): void
    {
        dump($this->router);

        // ...
    }

    // ...
}

I haven't added any tests yet, as I was hoping to get some feedback on my approach first.

[connorhu]

Here you can find a similar but much simpler implementation. My solution works without extending the autoloader.
3.3.x...connorhu:DoctrineMigrationsBundle:3.3.x

[derrabus]

This PR will require to register migrations as services, right? If we go down that road, why would I need them to be service subscribers? I mean, I could just inject all dependencies directly, couldn't I?

[HypeMC]

@derrabus The reason for my approach are the standard migration arguments: Connection $connection, LoggerInterface $logger. Connection would get autowired to the connection in Doctrine bundle, not the result of doctrine.migrations.dependency_factory::getConnection(), same goes for the logger. Perhaps I could use bindings instead 🤔 . I'll give it a try.

[HypeMC]

@derrabus I've updated the implementation to use bound arguments instead of service locators.

[AlexOstrovsky]

@greg0ire any plan when this will be merged?

[greg0ire]

No

[AlexOstrovsky]

@greg0ire what is blocking this from beeing merged?

[greg0ire]

For starters:

• There are conflicts.
• The CI should be green.
• The conversation with @derrabus must be resolved.

[greg0ire]

I know it's just a POC for now, but since I'm asked what's blocking, I'd add that docs are probably necessary for this sort of thing.