From 988c95b7ba21138ecab30f600bf2ec9050f49a5e Mon Sep 17 00:00:00 2001
From: Karson <karsonzhang@163.com>
Date: Thu, 14 Dec 2023 18:19:34 +0800
Subject: [PATCH] =?UTF-8?q?=E4=BF=AE=E5=A4=8D=E8=AF=AD=E8=A8=80=E6=A3=80?=
 =?UTF-8?q?=E6=B5=8B=E6=9C=AA=E5=8C=B9=E9=85=8D=E6=97=B6=E7=9A=84=E9=94=99?=
 =?UTF-8?q?=E8=AF=AF?=
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Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 library/think/Lang.php | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/library/think/Lang.php b/library/think/Lang.php
index 23887a2c..9e6adb3f 100644
--- a/library/think/Lang.php
+++ b/library/think/Lang.php
@@ -201,7 +201,7 @@ class Lang
         } elseif (isset($_SERVER['HTTP_ACCEPT_LANGUAGE'])) {
             // 自动侦测浏览器语言
             preg_match('/^([a-z\d\-]+)/i', $_SERVER['HTTP_ACCEPT_LANGUAGE'], $matches);
-            $langSet     = strtolower($matches[1]);
+            $langSet     = strtolower($matches[1] ?? '');
             $acceptLangs = Config::get('header_accept_lang');
 
             if (isset($acceptLangs[$langSet])) {