ContainerDerivativeDiscoveryDecorator.php

<?php

namespace Drupal\Core\Plugin\Discovery;

use Drupal\Component\Plugin\Discovery\DerivativeDiscoveryDecorator;

/**
 * Injects dependencies into derivers if they use ContainerDeriverInterface.
 *
 * @see \Drupal\Core\Plugin\Discovery\ContainerDeriverInterface
 */
class ContainerDerivativeDiscoveryDecorator extends DerivativeDiscoveryDecorator {
    
    /**
     * {@inheritdoc}
     */
    protected function getDeriver($base_plugin_id, $base_definition) {
        if (!isset($this->derivers[$base_plugin_id])) {
            $this->derivers[$base_plugin_id] = FALSE;
            $class = $this->getDeriverClass($base_definition);
            if ($class) {
                // If the deriver provides a factory method, pass the container to it.
                if (is_subclass_of($class, '\\Drupal\\Core\\Plugin\\Discovery\\ContainerDeriverInterface')) {
                    
                    /** @var \Drupal\Core\Plugin\Discovery\ContainerDeriverInterface $class */
                    $this->derivers[$base_plugin_id] = $class::create(\Drupal::getContainer(), $base_plugin_id);
                }
                else {
                    $this->derivers[$base_plugin_id] = new $class($base_plugin_id);
                }
            }
        }
        return $this->derivers[$base_plugin_id] ?: NULL;
    }

}