Clarify that lazy event listeners are built from the server container

Ref https://github.com/nextcloud/server/issues/27793

Signed-off-by: Christoph Wurst <christoph@winzerhof-wurst.at>

lib/private/EventDispatcher/ServiceEventListener.php

@@ -24,13 +24,15 @@ declare(strict_types=1);
  * along with this program. If not, see <http://www.gnu.org/licenses/>.
  *
  */
+
 namespace OC\EventDispatcher;
 
 use OCP\AppFramework\QueryException;
 use OCP\EventDispatcher\Event;
 use OCP\EventDispatcher\IEventListener;
-use OCP\IContainer;
+use OCP\IServerContainer;
 use Psr\Log\LoggerInterface;
+use function sprintf;
 
 /**
  * Lazy service event listener
@@ -40,7 +42,7 @@ use Psr\Log\LoggerInterface;
  */
 final class ServiceEventListener {
 
-	/** @var IContainer */
+	/** @var IServerContainer */
 	private $container;
 
 	/** @var string */
@@ -52,7 +54,7 @@ final class ServiceEventListener {
 	/** @var null|IEventListener */
 	private $service;
 
-	public function __construct(IContainer $container,
+	public function __construct(IServerContainer $container,
 								string $class,
 								LoggerInterface $logger) {
 		$this->container = $container;
@@ -63,11 +65,21 @@ final class ServiceEventListener {
 	public function __invoke(Event $event) {
 		if ($this->service === null) {
 			try {
+				// TODO: fetch from the app containers, otherwise any custom services,
+				//       parameters and aliases won't be resolved.
+				//       See https://github.com/nextcloud/server/issues/27793 for details.
 				$this->service = $this->container->query($this->class);
 			} catch (QueryException $e) {
-				$this->logger->error("Could not load event listener service " . $this->class, [
-					'exception' => $e,
-				]);
+				$this->logger->error(
+					sprintf(
+						'Could not load event listener service %s: %s. Make sure the class is auto-loadable by the Nextcloud server container',
+						$this->class,
+						$e->getMessage()
+					),
+					[
+						'exception' => $e,
+					]
+				);
 				return;
 			}
 		}