From 9bf4f4457f7e9f0c07f5ddc7a339858400b504eb Mon Sep 17 00:00:00 2001
From: Gang Wang <v-gaw@microsoft.com>
Date: Wed, 15 Oct 2025 03:12:12 +0000
Subject: [PATCH] Add the feature flag that allows users to opt out automatic
 UTF8 console encoding

---
 .../UILanguageOverride.cs                     | 23 +++++++++++--------
 src/Cli/dotnet/Program.cs                     |  9 +++++---
 2 files changed, 19 insertions(+), 13 deletions(-)

diff --git a/src/Cli/Microsoft.DotNet.Cli.Utils/UILanguageOverride.cs b/src/Cli/Microsoft.DotNet.Cli.Utils/UILanguageOverride.cs
index d76b1ba6d8e8..f28c5b5a1cd4 100644
--- a/src/Cli/Microsoft.DotNet.Cli.Utils/UILanguageOverride.cs
+++ b/src/Cli/Microsoft.DotNet.Cli.Utils/UILanguageOverride.cs
@@ -25,19 +25,22 @@ public static void Setup()
             FlowOverrideToChildProcesses(language);
         }
 
-        if (
-            !CultureInfo.CurrentUICulture.TwoLetterISOLanguageName.Equals("en", StringComparison.InvariantCultureIgnoreCase) &&
+        if (Environment.GetEnvironmentVariable("CONSOLE_USE_DEFAULT_ENCODING") != "1")
+        {
+            if (
+                !CultureInfo.CurrentUICulture.TwoLetterISOLanguageName.Equals("en", StringComparison.InvariantCultureIgnoreCase) &&
 #if NET
-            OperatingSystemSupportsUtf8()
+                OperatingSystemSupportsUtf8()
 #else
-            CurrentPlatformIsWindowsAndOfficiallySupportsUTF8Encoding()
+                CurrentPlatformIsWindowsAndOfficiallySupportsUTF8Encoding()
 #endif
-            )
-        {
-            // Setting both encodings causes a change in the CHCP, making it so we don't need to P-Invoke ourselves.
-            Console.OutputEncoding = s_defaultMultilingualEncoding;
-            Console.InputEncoding = s_defaultMultilingualEncoding;
-            // If the InputEncoding is not set, the encoding will work in CMD but not in Powershell, as the raw CHCP page won't be changed.
+                )
+            {
+                // Setting both encodings causes a change in the CHCP, making it so we don't need to P-Invoke ourselves.
+                Console.OutputEncoding = s_defaultMultilingualEncoding;
+                Console.InputEncoding = s_defaultMultilingualEncoding;
+                // If the InputEncoding is not set, the encoding will work in CMD but not in Powershell, as the raw CHCP page won't be changed.
+            }
         }
     }
 
diff --git a/src/Cli/dotnet/Program.cs b/src/Cli/dotnet/Program.cs
index cd82a15330f4..91f78339fd74 100644
--- a/src/Cli/dotnet/Program.cs
+++ b/src/Cli/dotnet/Program.cs
@@ -31,10 +31,13 @@ public static int Main(string[] args)
     {
         using AutomaticEncodingRestorer _ = new();
 
-        // Setting output encoding is not available on those platforms
-        if (UILanguageOverride.OperatingSystemSupportsUtf8())
+        if (Environment.GetEnvironmentVariable("CONSOLE_USE_DEFAULT_ENCODING") != "1")
         {
-            Console.OutputEncoding = Encoding.UTF8;
+            // Setting output encoding is not available on those platforms
+            if (UILanguageOverride.OperatingSystemSupportsUtf8())
+            {
+                Console.OutputEncoding = Encoding.UTF8;
+            }
         }
 
         DebugHelper.HandleDebugSwitch(ref args);