[clang-tools-extra] 7cc09c4 - Reland "[clang-tidy] Preserve line endings in macro-to-enum fixes" (#202271)

[via cfe-commits]

Author: Zeyi Xu
Date: 2026-06-09T09:52:00+08:00
New Revision: 7cc09c43384b16a8d8bfca809dae14c2c200451a

URL: https://github.com/llvm/llvm-project/commit/7cc09c43384b16a8d8bfca809dae14c2c200451a
DIFF: https://github.com/llvm/llvm-project/commit/7cc09c43384b16a8d8bfca809dae14c2c200451a.diff

LOG: Reland "[clang-tidy] Preserve line endings in macro-to-enum fixes" (#202271)

Use StringRef::detectEOL() when inserting enum braces so fix-its do not
mix LF into CRLF source files.

This reland fixes the previous buildbot failure by adding `--` in test
file.

Added: 
    clang-tools-extra/test/clang-tidy/checkers/modernize/Inputs/macro-to-enum/crlf.cpp
    clang-tools-extra/test/clang-tidy/checkers/modernize/Inputs/macro-to-enum/crlf.cpp.expected
    clang-tools-extra/test/clang-tidy/checkers/modernize/macro-to-enum-crlf.cpp

Modified: 
    clang-tools-extra/clang-tidy/modernize/MacroToEnumCheck.cpp
    clang-tools-extra/docs/ReleaseNotes.rst
    clang-tools-extra/test/.gitattributes

Removed: 
    


################################################################################
diff  --git a/clang-tools-extra/clang-tidy/modernize/MacroToEnumCheck.cpp b/clang-tools-extra/clang-tidy/modernize/MacroToEnumCheck.cpp
index 1c49c32f9fecb..aa4732ceba7e0 100644
--- a/clang-tools-extra/clang-tidy/modernize/MacroToEnumCheck.cpp
+++ b/clang-tools-extra/clang-tidy/modernize/MacroToEnumCheck.cpp
@@ -470,11 +470,15 @@ void MacroToEnumCallbacks::warnMacroEnum(const EnumMacro &Macro) const {
 void MacroToEnumCallbacks::fixEnumMacro(const MacroList &MacroList) const {
   SourceLocation Begin =
       MacroList.front().Directive->getMacroInfo()->getDefinitionLoc();
+  const StringRef LineEnding =
+      SM.getBufferData(SM.getFileID(Begin)).detectEOL();
+
   Begin = SM.translateLineCol(SM.getFileID(Begin),
                               SM.getSpellingLineNumber(Begin), 1);
   const DiagnosticBuilder Diagnostic =
       Check->diag(Begin, "replace macro with enum")
-      << FixItHint::CreateInsertion(Begin, "enum {\n");
+      << FixItHint::CreateInsertion(Begin,
+                                    (llvm::Twine("enum {") + LineEnding).str());
 
   for (size_t I = 0U; I < MacroList.size(); ++I) {
     const EnumMacro &Macro = MacroList[I];
@@ -503,7 +507,8 @@ void MacroToEnumCallbacks::fixEnumMacro(const MacroList &MacroList) const {
       LangOpts);
   End = SM.translateLineCol(SM.getFileID(End),
                             SM.getSpellingLineNumber(End) + 1, 1);
-  Diagnostic << FixItHint::CreateInsertion(End, "};\n");
+  Diagnostic << FixItHint::CreateInsertion(
+      End, (llvm::Twine("};") + LineEnding).str());
 }
 
 void MacroToEnumCheck::registerPPCallbacks(const SourceManager &SM,

diff  --git a/clang-tools-extra/docs/ReleaseNotes.rst b/clang-tools-extra/docs/ReleaseNotes.rst
index 9703bb8f17208..c369b1fd8b373 100644
--- a/clang-tools-extra/docs/ReleaseNotes.rst
+++ b/clang-tools-extra/docs/ReleaseNotes.rst
@@ -581,6 +581,10 @@ Changes in existing checks
   positives on project headers that use the same name as a standard library
   header.
 
+- Improved :doc:`modernize-macro-to-enum
+  <clang-tidy/checks/modernize/macro-to-enum>` check by preserving source file
+  line endings in fix-it replacements.
+
 - Improved :doc:`modernize-pass-by-value
   <clang-tidy/checks/modernize/pass-by-value>` check by adding `IgnoreMacros`
   option to suppress warnings in macros.

diff  --git a/clang-tools-extra/test/.gitattributes b/clang-tools-extra/test/.gitattributes
index 3d4df1e9976bc..3c39030a95eab 100644
--- a/clang-tools-extra/test/.gitattributes
+++ b/clang-tools-extra/test/.gitattributes
@@ -13,3 +13,5 @@ clang-tidy/infrastructure/export-diagnostics.cpp -text
 # These test input files rely on two-byte Windows (CRLF) line endings.
 clang-apply-replacements/Inputs/crlf/crlf.cpp -text
 clang-apply-replacements/Inputs/crlf/crlf.cpp.expected -text
+clang-tidy/checkers/modernize/Inputs/macro-to-enum/crlf.cpp -text
+clang-tidy/checkers/modernize/Inputs/macro-to-enum/crlf.cpp.expected -text

diff  --git a/clang-tools-extra/test/clang-tidy/checkers/modernize/Inputs/macro-to-enum/crlf.cpp b/clang-tools-extra/test/clang-tidy/checkers/modernize/Inputs/macro-to-enum/crlf.cpp
new file mode 100644
index 0000000000000..c05d3cd5823ba
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/checkers/modernize/Inputs/macro-to-enum/crlf.cpp
@@ -0,0 +1,2 @@
+#define RED 1
+#define GREEN 2

diff  --git a/clang-tools-extra/test/clang-tidy/checkers/modernize/Inputs/macro-to-enum/crlf.cpp.expected b/clang-tools-extra/test/clang-tidy/checkers/modernize/Inputs/macro-to-enum/crlf.cpp.expected
new file mode 100644
index 0000000000000..31100df321bb3
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/checkers/modernize/Inputs/macro-to-enum/crlf.cpp.expected
@@ -0,0 +1,4 @@
+enum {
+RED = 1,
+GREEN = 2
+};

diff  --git a/clang-tools-extra/test/clang-tidy/checkers/modernize/macro-to-enum-crlf.cpp b/clang-tools-extra/test/clang-tidy/checkers/modernize/macro-to-enum-crlf.cpp
new file mode 100644
index 0000000000000..3420079902f63
--- /dev/null
+++ b/clang-tools-extra/test/clang-tidy/checkers/modernize/macro-to-enum-crlf.cpp
@@ -0,0 +1,6 @@
+// Verify the fix-it preserves CRLF line endings.
+
+// RUN: cp %S/Inputs/macro-to-enum/crlf.cpp %t.cpp
+// RUN: chmod u+w %t.cpp
+// RUN: clang-tidy %t.cpp -fix --checks='-*,modernize-macro-to-enum' -- > %t.out 2>&1
+// RUN: 
diff  %t.cpp %S/Inputs/macro-to-enum/crlf.cpp.expected