If `$recipientIDs` empty this will cause an exception

diff --git a/wcfsetup/install/files/lib/system/user/notification/UserNotificationHandler.class.php b/wcfsetup/install/files/lib/system/user/notification/UserNotificationHandler.class.php
index 481cc9dbd66e2c594c21f701ccfe44d72bb3d1e6..9c082239413cf1255c656203168c3d447bbd4b29 100644 (file)
--- a/wcfsetup/install/files/lib/system/user/notification/UserNotificationHandler.class.php
+++ b/wcfsetup/install/files/lib/system/user/notification/UserNotificationHandler.class.php
@@ -141,6 +141,9 @@ class UserNotificationHandler extends SingletonFactory
         // @deprecated 5.2 This event exposes incomplete data and should not
         // be used, please use the following events instead.
         EventHandler::getInstance()->fireAction($this, 'fireEvent', $parameters);
+        if ($recipientIDs === []) {
+            return;
+        }
 
         // find existing notifications
         $conditions = new PreparedStatementConditionBuilder();