preserve global user switch in cronjob, fixes #2242

Closes #2242

Merge request studip/studip!1475

lib/cronjobs/send_mail_notifications.class.php

@@ -94,6 +94,8 @@ class SendMailNotificationsJob extends CronJob
      */
     public function execute($last_result, $parameters = [])
     {
+        $cli_user = $GLOBALS['user'];
+
         $notification = new ModulesNotification();
 
         $query = "SELECT DISTINCT user_id
@@ -112,6 +114,8 @@ class SendMailNotificationsJob extends CronJob
                     return;
                 }
 
+                $GLOBALS['user'] = new Seminar_user($user);
+
                 $ok = false;
                 $mailmessage = $notification->getAllNotifications($user->id);
 
@@ -135,5 +139,7 @@ class SendMailNotificationsJob extends CronJob
                 }
             }
         );
+
+        $GLOBALS['user'] = $cli_user;
     }
 }