target_disable_clang_tidy(fmt) does not really help

[ClausKlein]

ninja
# ...
/Users/clausklein/.cache/CPM/fmt/15c05aa781ab44fa13a906fe5737c1d14e5edee9/include/fmt/format.h:3036:51: error: all parameters should be named in a function [hicpp-named-parameter,readability-named-parameter,-warnings-as-errors]
constexpr auto operator"" _a(const char* s, size_t) -> detail::udl_arg<char> {
                                                  ^
                                                   /*unused*/
/Users/clausklein/.cache/CPM/fmt/15c05aa781ab44fa13a906fe5737c1d14e5edee9/include/fmt/format.h:3043:62: error: parameter name 's' is too short, expected at least 3 characters [readability-identifier-length,-warnings-as-errors]
FMT_DEPRECATED constexpr auto operator"" _format(const char* s, size_t n)
                                                             ^
/Users/clausklein/Workspace/cpp/ModernCmakeStarter/source/greeter.cpp:4:1: error: do not use namespace using-directives; use using-declarations instead [google-build-using-namespace,-warnings-as-errors]
using namespace greeter;
^
58184 warnings generated.
Suppressed 56453 warnings (56449 in non-user code, 4 with check filters).
Use -header-filter=.* to display errors from all non-system headers. Use -system-headers to display errors from system headers as well.
1018 warnings treated as errors
ninja: build stopped: subcommand failed.
Claus-iMac:build-ModernCmakeStarter-Debug clausklein$ builddriver ninja
builddriver executing: 'ninja'
Compilation FAILED in 6.547162 seconds
Number of warnings: 0
Number of errors: 1018
Last Error:
  Message: "do not use namespace using-directives; use using-declarations instead [google-build-using-namespace,-warnings-as-errors]"
  Path: /Users/clausklein/Workspace/cpp/ModernCmakeStarter/source/greeter.cpp
  Line Number: 4
  Column: 1
For full log, please open: /var/folders/wb/ckvxxgls5db7qyhqq4y5_l1c0000gq/T/build-snfb9p3a.log
Claus-iMac:build-ModernCmakeStarter-Debug clausklein$ ninja -nv
[1/4] /usr/local/Cellar/cmake/3.24.1/bin/cmake -E __run_co_compile --launcher=/usr/local/bin/ccache --tidy="/usr/local/opt/llvm/bin/clang-tidy;-extra-arg=-Wno-unknown-warning-option;-warnings-as-errors=*;-extra-arg=-std=c++20;--extra-arg-before=--driver-mode=g++" --source=/Users/clausklein/Workspace/cpp/ModernCmakeStarter/source/greeter.cpp -- /Applications/Xcode.app/Contents/Developer/usr/bin/g++ -DFMT_LOCALE -I/Users/clausklein/.cache/CPM/fmt/15c05aa781ab44fa13a906fe5737c1d14e5edee9/include -isystem /Users/clausklein/Workspace/cpp/ModernCmakeStarter/include -g -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX12.3.sdk -fcolor-diagnostics -std=c++20 -MD -MT _deps/greeter-build/CMakeFiles/greeter.dir/source/greeter.cpp.o -MF _deps/greeter-build/CMakeFiles/greeter.dir/source/greeter.cpp.o.d -o _deps/greeter-build/CMakeFiles/greeter.dir/source/greeter.cpp.o -c /Users/clausklein/Workspace/cpp/ModernCmakeStarter/source/greeter.cpp
[2/4] : && /usr/local/Cellar/cmake/3.24.1/bin/cmake -E rm -f _deps/greeter-build/libgreeter.a && /usr/bin/ar qc _deps/greeter-build/libgreeter.a  _deps/greeter-build/CMakeFiles/greeter.dir/source/greeter.cpp.o && /usr/bin/ranlib _deps/greeter-build/libgreeter.a && /usr/local/Cellar/cmake/3.24.1/bin/cmake -E touch _deps/greeter-build/libgreeter.a && :
[3/4] : && /Applications/Xcode.app/Contents/Developer/usr/bin/g++ -g -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX12.3.sdk -Wl,-search_paths_first -Wl,-headerpad_max_install_names  standalone/CMakeFiles/GreeterStandalone.dir/source/main.cpp.o -o standalone/GreeterStandalone  _deps/greeter-build/libgreeter.a  _deps/fmt-build/libfmtd.a && :
[4/4] : && /Applications/Xcode.app/Contents/Developer/usr/bin/g++ -g -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX12.3.sdk -Wl,-search_paths_first -Wl,-headerpad_max_install_names  test/CMakeFiles/GreeterTests.dir/source/main.cpp.o test/CMakeFiles/GreeterTests.dir/source/greeter.cpp.o -o test/GreeterTests  _deps/greeter-build/libgreeter.a  _deps/fmt-build/libfmtd.a && :
Claus-iMac:build-ModernCmakeStarter-Debug clausklein$ 

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[ClausKlein]

see ClausKlein/ModernCmakeStarter@e57657f

[aminya]

Clang tidy returns the warnings from those headers if your config file includes all headers.

[ClausKlein]

Yes, the only way I know to prevent this is to patch the CMake generated compile_commands.json file:

Claus-iMac:ModernCmakeStarter clausklein$ make -n check
perl -i.bak -p -e 's#-W[-\w]+(=\d)?\b##g;' -e 's#-I(/Users/clausklein/.cache/CPM)#-isystem $1#g;' ./build-ModernCmakeStarter-Debug/compile_commands.json
run-clang-tidy -p ./build-ModernCmakeStarter-Debug /Users/clausklein/Workspace/cpp/ModernCmakeStarter
Claus-iMac:ModernCmakeStarter clausklein$ 

[aminya]

What does this change?

[ClausKlein]

What does this change?

I use CMP.cmake to fetch my dependencies. With perl script, I replace all -I include path to CMP cache to -isystem include path. And I delete all -W options because some gcc warnings are not valid vor clang.

When you use vpkg or conan the imported CMake config packages use implizit this -isystem include path.

Background info: I use the CPM_SOURCE_CACHE environment variable in my makefile!

perl -i.bak -p -e 's#-W[-\w]+(=\d)?\b##g;' -e 's#-I(${CPM_SOURCE_CACHE})#-isystem $$1#g;' $(BUILD_DIR)/compile_commands.json