From a9f0705c1bf8dc3c41fc97262e49424d4d65320d Mon Sep 17 00:00:00 2001
From: Christian Flothmann <christian.flothmann@qossmic.com>
Date: Thu, 2 Nov 2023 12:02:02 +0100
Subject: [PATCH] ensure string type with mbstring func overloading enabled

---
 src/Symfony/Component/HttpFoundation/HeaderUtils.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/Symfony/Component/HttpFoundation/HeaderUtils.php b/src/Symfony/Component/HttpFoundation/HeaderUtils.php
index f91c7e1d97d86..3456edace0dc1 100644
--- a/src/Symfony/Component/HttpFoundation/HeaderUtils.php
+++ b/src/Symfony/Component/HttpFoundation/HeaderUtils.php
@@ -256,7 +256,7 @@ public static function parseQuery(string $query, bool $ignoreBrackets = false, s
     private static function groupParts(array $matches, string $separators, bool $first = true): array
     {
         $separator = $separators[0];
-        $separators = substr($separators, 1);
+        $separators = substr($separators, 1) ?: '';
         $i = 0;
 
         if ('' === $separators && !$first) {