prevent php8 warning, fixes #6166

Closes #6166

Merge request studip/studip!4672

1 files changed, 3 insertions, 6 deletions

diff --git a/lib/classes/Seminar_Perm.php b/lib/classes/Seminar_Perm.php
index e56835f..63671ec 100644
--- a/lib/classes/Seminar_Perm.php
+++ b/lib/classes/Seminar_Perm.php
@@ -73,9 +73,9 @@ class Seminar_Perm
     {
         global $user;
         if (!$user_id) {
-            $user_id = $user->id;
+            $user_id = $user->id ?? null;
         }
-        if ($user_id && $user_id == $user->id) {
+        if ($user_id && $user && $user_id == $user->id) {
             return $user->perms;
         }
         if ($user_id && isset($this->studip_perms['studip'][$user_id])) {
@@ -83,10 +83,7 @@ class Seminar_Perm
         }
         if ($user_id && $user_id !== 'nobody') {
             $query = "SELECT perms FROM auth_user_md5 WHERE user_id = :user_id";
-            $statement = DBManager::get()->prepare($query);
-            $statement->bindValue(':user_id', $user_id);
-            $statement->execute();
-            $perms = $statement->fetchColumn();
+            $perms = DBManager::get()->fetchColumn($query, [':user_id' => $user_id]);
 
             return $this->studip_perms['studip'][$user_id] = $perms;
         }