From e2d21a7f137a82b3f164f96bdf9aca6c5dfdc0a0 Mon Sep 17 00:00:00 2001
From: Cyperghost <olaf_schmitz_1@t-online.de>
Date: Thu, 1 Feb 2024 14:37:07 +0100
Subject: [PATCH] If `$recipientIDs` empty this will cause an exception

---
 .../system/user/notification/UserNotificationHandler.class.php | 3 +++
 1 file changed, 3 insertions(+)

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 481cc9dbd6..9c08223941 100644
--- 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();
-- 
2.20.1