UpdateServiceProvider.php

<?php

namespace Drupal\Core\Update;

use Drupal\Core\DependencyInjection\ContainerBuilder;
use Drupal\Core\DependencyInjection\ServiceModifierInterface;
use Drupal\Core\DependencyInjection\ServiceProviderInterface;
use Symfony\Component\DependencyInjection\Compiler\PassConfig;
use Symfony\Component\DependencyInjection\Definition;
use Symfony\Component\DependencyInjection\Reference;

/**
 * Customizes the container for running updates.
 */
class UpdateServiceProvider implements ServiceProviderInterface, ServiceModifierInterface {
    
    /**
     * {@inheritdoc}
     */
    public function register(ContainerBuilder $container) {
        $definition = new Definition('Drupal\\Core\\Cache\\NullBackend', [
            'null',
        ]);
        if (method_exists($definition, 'getDeprecation')) {
            $definition->setDeprecated('drupal/core', '8.8.0', 'The "%service_id%\\" service is deprecated. While updating Drupal all caches use \\Drupal\\Core\\Update\\UpdateBackend. See https://www.drupal.org/node/3066407');
        }
        else {
            // @todo Remove when we no longer support Symfony 4 in
            // https://www.drupal.org/project/drupal/issues/3197729
            $definition->setDeprecated(TRUE, 'The "%service_id%\\" service is deprecated. While updating Drupal all caches use \\Drupal\\Core\\Update\\UpdateBackend. See https://www.drupal.org/node/3066407');
        }
        $definition->setPublic(TRUE);
        $container->setDefinition('cache.null', $definition);
        // Decorate the cache factory in order to use
        // \Drupal\Core\Update\UpdateBackend while running updates.
        $container->register('update.cache_factory', UpdateCacheBackendFactory::class)
            ->setDecoratedService('cache_factory')
            ->addArgument(new Reference('update.cache_factory.inner'));
        $container->addCompilerPass(new UpdateCompilerPass(), PassConfig::TYPE_REMOVE, 128);
    }
    
    /**
     * {@inheritdoc}
     */
    public function alter(ContainerBuilder $container) {
        // The alias-based processor requires the path_alias entity schema to be
        // installed, so we prevent it from being registered to the path processor
        // manager. We do this by removing the tags that the compiler pass looks
        // for. This means that the URL generator can safely be used during the
        // database update process.
        if ($container->hasDefinition('path_alias.path_processor')) {
            $container->getDefinition('path_alias.path_processor')
                ->clearTag('path_processor_inbound')
                ->clearTag('path_processor_outbound');
        }
    }

}