Issue #3231996: Ensure file system is writeable

src/Validator/WritableFileSystemValidator.php

@@ -9,6 +9,9 @@ use Drupal\automatic_updates\Validation\ValidationResult;
 use Drupal\Core\StringTranslation\StringTranslationTrait;
 use Symfony\Component\EventDispatcher\EventSubscriberInterface;
 
+/**
+ * Checks that the file system is writable before updating.
+ */
 class WritableFileSystemValidator implements EventSubscriberInterface {
 
   use StringTranslationTrait;
@@ -77,6 +80,7 @@ class WritableFileSystemValidator implements EventSubscriberInterface {
   public static function getSubscribedEvents() {
     return [
       AutomaticUpdatesEvents::READINESS_CHECK => 'checkPermissions',
+      AutomaticUpdatesEvents::PRE_START => 'checkPermissions',
     ];
   }