Symfony Automatic Service Loading fails with "Class does not exist"

Question

I am trying the new automatic service loading using Symfony's Dependency Injection component (stand-alone, not within a Symfony app), version v3.3.13.

If I manually define a service, the class is loaded correctly:

# services.yml
myasset:
    class: Mysite\Asset\Asset

# in a PHP file
$container->get('myasset'); # works

If I set up automatic loading, it fails with the error message: ReflectionException: Class does not exist in /var/www/vendor/symfony/dependency-injection/ContainerBuilder.php on line 1070

# services.yml
    _defaults:
        autowire: true
        autoconfigure: true
        public: false

    Bloggi\:
        resource: '../src/*'
        public: true

# in a PHP file
$container->get(Mysite\Asset\Asset::class);

The reason it fails is because the classes are found and service definitions created, but the class attribute on the definition is null for the automatically loaded services.

Answer 1

My DIC configuration looked like:

use Symfony\Component\DependencyInjection\ContainerBuilder;
use Symfony\Component\Config\FileLocator;
use Symfony\Component\DependencyInjection\Loader\YamlFileLoader;

$container = new ContainerBuilder();
$loader = new YamlFileLoader($container, new FileLocator(__DIR__));
$loader->load(__DIR__ . '/../config/services.yml');

The missing line was $container->compile();

The working definition

use Symfony\Component\DependencyInjection\ContainerBuilder;
use Symfony\Component\Config\FileLocator;
use Symfony\Component\DependencyInjection\Loader\YamlFileLoader;

$container = new ContainerBuilder();
$loader = new YamlFileLoader($container, new FileLocator(__DIR__));
$loader->load(__DIR__ . '/../config/services.yml');
$container->compile();