issue #3340050: Use FileSystemInterface rather than FileSystem.

src/Form/UploadForm.php

@@ -4,7 +4,7 @@ namespace Drupal\pack_upload\Form;
 
 use Drupal\Core\Form\FormBase;
 use Drupal\Core\Form\FormStateInterface;
-use Drupal\Core\File\FileSystem;
+use Drupal\Core\File\FileSystemInterface;
 use Drupal\Core\Entity\EntityTypeManagerInterface;
 use Symfony\Component\DependencyInjection\ContainerInterface;
 use Drupal\pack_upload\ArchiverFactory;
@@ -19,7 +19,7 @@ class UploadForm extends FormBase {
   /**
    * Drupal File System service.
    *
-   * @var \Drupal\Core\File\FileSystem
+   * @var \Drupal\Core\File\FileSystemInterface
    */
   protected $fileSystem;
 
@@ -54,7 +54,7 @@ class UploadForm extends FormBase {
   /**
    * Constructor for \Drupal\pack_upload\Form\UploadForm class.
    *
-   * @param \Drupal\Core\File\FileSystem $file_system
+   * @param \Drupal\Core\File\FileSystemInterface $file_system
    *   The Form Builder service.
    * @param \Drupal\Core\Entity\EntityTypeManagerInterface $entity_type_manager
    *   The Entity type manager service.
@@ -66,7 +66,7 @@ class UploadForm extends FormBase {
    *   The config factory service.
    */
   public function __construct(
-    FileSystem $file_system,
+    FileSystemInterface $file_system,
     EntityTypeManagerInterface $entity_type_manager,
     ArchiverFactory $archiver_factory,
     StreamWrapperManager $stream_wrapper_manager,