[Lldb-commits] [lldb] [lldb][windows] re-enable unicode tests on Windows (PR #190828)

[Charles Zablit via lldb-commits]

https://github.com/charles-zablit created https://github.com/llvm/llvm-project/pull/190828

This patch re-enables unicode tests on Windows by improving the `Terminal::SupportsUnicode` check.

>From 3b14c3d7fdeec755b6be0918e94a330789c65e6e Mon Sep 17 00:00:00 2001
From: Charles Zablit <c_zablit at apple.com>
Date: Tue, 7 Apr 2026 18:56:00 +0100
Subject: [PATCH] [lldb][windows] re-enable unicode tests on Windows

---
 .../Python/lldbsuite/test/decorators.py        | 18 ++++++++++++++----
 lldb/source/Host/common/Terminal.cpp           |  6 +++++-
 2 files changed, 19 insertions(+), 5 deletions(-)

diff --git a/lldb/packages/Python/lldbsuite/test/decorators.py b/lldb/packages/Python/lldbsuite/test/decorators.py
index 8fd38c62f7b16..165833808dd2d 100644
--- a/lldb/packages/Python/lldbsuite/test/decorators.py
+++ b/lldb/packages/Python/lldbsuite/test/decorators.py
@@ -480,15 +480,25 @@ def unicode_test(func):
     """Decorate the item as a test which requires Unicode to be enabled.
 
     lldb checks the value of the `LANG` environment variable for the substring "utf-8"
-    to determine if the terminal supports Unicode (except on Windows, where we assume
-    it's always supported).
+    to determine if the terminal supports Unicode (except on Windows, where stdout
+    being connected to an interactive console is used as the signal instead).
     This decorator sets LANG to `utf-8` before running the test and resets it to its
     previous value afterwards.
     """
 
     if sys.platform == "win32":
-        # Unicode support on Windows is flaky in CI.
-        return expectedFailureWindows
+        import ctypes
+
+        STD_OUTPUT_HANDLE = -11
+        FILE_TYPE_CHAR = 0x0002
+        handle = ctypes.windll.kernel32.GetStdHandle(STD_OUTPUT_HANDLE)
+        file_type = ctypes.windll.kernel32.GetFileType(handle)
+        # Mirror Terminal::SupportsUnicode(): Unicode is supported only when
+        # stdout is connected to a real console.
+        if file_type != FILE_TYPE_CHAR:
+            return unittest.skip(
+                "Unicode test requires an interactive console (stderr is redirected)"
+            )
 
     def unicode_wrapped(*args, **kwargs):
         import os
diff --git a/lldb/source/Host/common/Terminal.cpp b/lldb/source/Host/common/Terminal.cpp
index b6d09425e956e..2ddfb6fc3bebe 100644
--- a/lldb/source/Host/common/Terminal.cpp
+++ b/lldb/source/Host/common/Terminal.cpp
@@ -20,6 +20,10 @@
 #include <termios.h>
 #endif
 
+#ifdef _WIN32
+#include "lldb/Host/windows/windows.h"
+#endif
+
 using namespace lldb_private;
 
 struct Terminal::Data {
@@ -402,7 +406,7 @@ llvm::Error Terminal::SetHardwareFlowControl(bool enabled) {
 
 bool Terminal::SupportsUnicode() {
 #ifdef _WIN32
-  return true;
+  return ::GetFileType(GetStdHandle(STD_OUTPUT_HANDLE)) == FILE_TYPE_CHAR;
 #else
   static std::optional<bool> g_result;
   if (g_result)