[clang-tools-extra] [clang-tidy] Skip system macros in readability-identifier-naming check (PR #132016)

[Carlos Galvez via cfe-commits]

https://github.com/carlosgalvezp created https://github.com/llvm/llvm-project/pull/132016

Currently, the check is processing system macros. Most importantly, it tries to find .clang-tidy files associated with those files, if the option GetConfigPerFile (on by default) is active.

This is problematic for a number of reasons:

- System macros cannot be acted upon (renamed), so it's wasted work.
- When the main .cpp file includes a system header, clang-tidy tries to find the .clang-tidy file for that system header. When that system header is a 3rd-party repository, they may have their own .clang-tidy file, which may not be compatible with the current version of clang-tidy. So, clang-tidy may fail to analyze our main.cpp file, only because it includes a 3rd-party system header whose .clang-tidy file is incompatible with our clang-tidy binary.

Therefore, skip system macros in this check.

>From dd010cc21df6000831af2e693805461262201546 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Carlos=20G=C3=A1lvez?= <carlos.galvez at zenseact.com>
Date: Wed, 19 Mar 2025 12:28:49 +0000
Subject: [PATCH] [clang-tidy] Skip system macros in
 readability-identifier-naming check

Currently, the check is processing system macros. Most importantly,
it tries to find .clang-tidy files associated with those files, if
the option GetConfigPerFile (on by default) is active.

This is problematic for a number of reasons:

- System macros cannot be acted upon (renamed), so it's wasted work.
- When the main .cpp file includes a system header, clang-tidy tries
  to find the .clang-tidy file for that system header. When that system
  header is a 3rd-party repository, they may have their own .clang-tidy
  file, which may not be compatible with the current version of
  clang-tidy. So, clang-tidy may fail to analyze our main.cpp file,
  only because it includes a 3rd-party system header whose .clang-tidy
  file is incompatible with our clang-tidy binary.

Therefore, skip system macros in this check.
---
 clang-tools-extra/clang-tidy/utils/RenamerClangTidyCheck.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/clang-tools-extra/clang-tidy/utils/RenamerClangTidyCheck.cpp b/clang-tools-extra/clang-tidy/utils/RenamerClangTidyCheck.cpp
index 9104723c7f1c0..59e11ca51a0ae 100644
--- a/clang-tools-extra/clang-tidy/utils/RenamerClangTidyCheck.cpp
+++ b/clang-tools-extra/clang-tidy/utils/RenamerClangTidyCheck.cpp
@@ -194,6 +194,8 @@ class RenamerClangTidyCheckPPCallbacks : public PPCallbacks {
       return;
     if (SM.isWrittenInCommandLineFile(MacroNameTok.getLocation()))
       return;
+    if (SM.isInSystemHeader(MacroNameTok.getLocation()))
+      return;
     Check->checkMacro(MacroNameTok, Info, SM);
   }