Fix possible invalid value for explode

See #2534

diff --git a/wcfsetup/install/files/lib/data/user/group/UserGroup.class.php b/wcfsetup/install/files/lib/data/user/group/UserGroup.class.php
index 7ecc873fdae518ada388cb95dfd384f28c28755e..e572b25086bab6fc5674c154dfc54e6fc9fac575 100644 (file)
--- a/wcfsetup/install/files/lib/data/user/group/UserGroup.class.php
+++ b/wcfsetup/install/files/lib/data/user/group/UserGroup.class.php
@@ -199,7 +199,7 @@ class UserGroup extends DatabaseObject implements ITitledObject {
         */
        public static function isAccessibleGroup(array $groupIDs = []) {
                if (self::$accessibleGroups === null) {
-                       self::$accessibleGroups = explode(',', WCF::getSession()->getPermission('admin.user.accessibleGroups'));
+                       self::$accessibleGroups = explode(',', WCF::getSession()->getPermission('admin.user.accessibleGroups') ?: '');
                }
                
                if (empty($groupIDs)) return false;