[clang] [Clang] Try to fix data race on HasColors after #202441 (PR #206975)

[Joseph Huber via cfe-commits]

https://github.com/jhuber6 created https://github.com/llvm/llvm-project/pull/206975

Summary:
The clangd users call these functions in multi-thraeded contexts. The
raw_fd_stream has_colors query is cached, which was giving some data
races. Just use the process-level check for now.


>From 684080dce35b8de4f367779a6ab87ab95b2c962e Mon Sep 17 00:00:00 2001
From: Joseph Huber <huberjn at outlook.com>
Date: Wed, 1 Jul 2026 08:03:30 -0500
Subject: [PATCH] [Clang] Try to fix data race on HasColors after #202441

Summary:
The clangd users call these functions in multi-thraeded contexts. The
raw_fd_stream has_colors query is cached, which was giving some data
races. Just use the process-level check for now.
---
 clang/lib/Basic/Warnings.cpp | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/clang/lib/Basic/Warnings.cpp b/clang/lib/Basic/Warnings.cpp
index 8adf339b3e5eb..91cce2e45d5f4 100644
--- a/clang/lib/Basic/Warnings.cpp
+++ b/clang/lib/Basic/Warnings.cpp
@@ -21,15 +21,18 @@
 //
 // Remark options are also handled here, analogously, except that they are much
 // simpler because a remark can't be promoted to an error.
+
 #include "clang/Basic/AllDiagnostics.h"
 #include "clang/Basic/Diagnostic.h"
 #include "clang/Basic/DiagnosticDriver.h"
 #include "clang/Basic/DiagnosticIDs.h"
 #include "clang/Basic/DiagnosticOptions.h"
 #include "llvm/ADT/StringRef.h"
+#include "llvm/Support/Process.h"
 #include "llvm/Support/VirtualFileSystem.h"
 #include "llvm/Support/raw_ostream.h"
 #include <cstring>
+
 using namespace clang;
 
 // EmitUnknownDiagWarning - Emit a warning and typo hint for unknown warning
@@ -54,7 +57,8 @@ void clang::ProcessWarningOptions(DiagnosticsEngine &Diags,
 
   Diags.setElideType(Opts.ElideType);
   Diags.setPrintTemplateTree(Opts.ShowTemplateTree);
-  Diags.setShowColors(Opts.showColors(llvm::errs().has_colors()));
+  Diags.setShowColors(
+      Opts.showColors(llvm::sys::Process::StandardErrHasColors()));
 
   // Handle -ferror-limit
   if (Opts.ErrorLimit)