[RFC] Support decorators

[BoShurik]

It would be great to have something like this:

return [
    ApiInterface::class => Reference::to(Api::class),
    CacheApi::class => Reference::decorate(ApiInterface::class, $priority = 0),
    // To log only real api calls
    'app.api.logged.calls' => Reference::decorate(ApiInterface::class, $priority = 10, [
        'context' => 'calls',
    ], LogApi::class), 
    // To log application api access
    'app.api.logged.access' => Reference::decorate(ApiInterface::class, $priority = -10, [
        'context' => 'access',
    ], LogApi::class), 
];

class CacheApi implements ApiInterface
{
    public function __construct(ApiInterface $decorated, CacheItemPoolInterface $cache)
    {
        //
    }
}

class LogApi implements ApiInterface
{
    public function __construct(ApiInterface $decorated, LoggerInterface $logger, string $context)
    {
        //
    }
}

$api = $container->get(ApiInterface::class); // LogApi (access) instance

Now it will be:

return [
    ApiInterface::class => function (ContainerInterface $container) {
        $logger = $container->get(LoggerInterface::class);
        $cache = $container->get(CacheItemPoolInterface::class);

        return new LogApi(
            new CacheApi(
                new LogApi(
                    $container->get(Api::class),
                    $logger,
                    'calls'
                ),
                $cache
            ),
            $logger,
            'access'
        );
    },
];

And it's impossible to register decorators by modules (e.g. debug decorators)

https://symfony.com/doc/current/service_container/service_decoration.html
https://php-di.org/doc/definition-overriding.html#decorators
https://laravel.com/docs/8.x/container#extending-bindings

[yiiliveext]

https://github.com/yiisoft/yii-debug/blob/master/src/DebugServiceProvider.php

[BoShurik]

As I understand it will be impossible with reworked service providers

[samdark]

Implemented via service providers.

[samdark]

@BoShurik please check if new service provider extensions are what you've meant.

[BoShurik]

@samdark yes it is. Thanks.
As I understand you can't decorate service in one provider extension multiple times, but it's not that important