From b0c1b0895dc1367e0473ec5e5c7ccc791cbcac04 Mon Sep 17 00:00:00 2001
From: Nicolas Dorier <nicolas.dorier@gmail.com>
Date: Mon, 17 Apr 2023 10:53:45 +0900
Subject: [PATCH] Fix crash if auto detect language on checkout page, and the
 language couldn't be detected (Fix #4881) (#4888)

---
 BTCPayServer/Controllers/UIInvoiceController.UI.cs    | 2 +-
 BTCPayServer/Views/UIStores/CheckoutAppearance.cshtml | 2 +-
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/BTCPayServer/Controllers/UIInvoiceController.UI.cs b/BTCPayServer/Controllers/UIInvoiceController.UI.cs
index 367a73309..bb5b7f119 100644
--- a/BTCPayServer/Controllers/UIInvoiceController.UI.cs
+++ b/BTCPayServer/Controllers/UIInvoiceController.UI.cs
@@ -754,7 +754,7 @@ namespace BTCPayServer.Controllers
             {
                 case "auto":
                 case null when storeBlob.AutoDetectLanguage:
-                    lang = _languageService.AutoDetectLanguageUsingHeader(HttpContext.Request.Headers, null).Code;
+                    lang = _languageService.AutoDetectLanguageUsingHeader(HttpContext.Request.Headers, null)?.Code;
                     break;
                 case { } langs when !string.IsNullOrEmpty(langs):
                     {
diff --git a/BTCPayServer/Views/UIStores/CheckoutAppearance.cshtml b/BTCPayServer/Views/UIStores/CheckoutAppearance.cshtml
index ca8316acb..76fa3d32f 100644
--- a/BTCPayServer/Views/UIStores/CheckoutAppearance.cshtml
+++ b/BTCPayServer/Views/UIStores/CheckoutAppearance.cshtml
@@ -167,7 +167,7 @@
                 <div class="form-check">
                     <input asp-for="AutoDetectLanguage" type="checkbox" class="form-check-input" />
                     <label asp-for="AutoDetectLanguage" class="form-check-label"></label>
-                    <div class="form-text">Detects the language of the customer's browser with 99.9% accuracy.</div>
+                    <div class="form-text">Detects the language of the customer's browser.</div>
                 </div>
             </div>
             <div class="form-group">