Fix ci_test_clang_libcxx_cxx* jobs silently building without warnings

CMake only seeds CMAKE_CXX_FLAGS from the CXXFLAGS environment variable
when the cache entry is unset, so the explicit -DCMAKE_CXX_FLAGS="-stdlib=libc++"
argument made it ignore CXXFLAGS="${CLANG_CXXFLAGS}" entirely. The six
ci_test_standards_clang (..., libcxx) jobs therefore compiled without
-Weverything/-Werror while their libstdc++ siblings did use them.

Pass -stdlib=libc++ through the same CXXFLAGS value instead of a separate
-D argument, and give the target its own build directory
(build_clang_libcxx_cxx${CXX_STANDARD}) so it no longer shares a CMake
cache with the libstdc++ variant. Suppress the resulting
-Wthread-safety-negative finding from libc++'s std::mutex annotations,
which fires on doctest's reporters in this translation unit only.

Part of #5715

Signed-off-by: Niels Lohmann <mail@nlohmann.me>
This commit is contained in:
Niels Lohmann
2026-09-30 09:51:14 +02:00
parent cff4138f34
commit 2a76599925
2 changed files with 23 additions and 5 deletions
+5 -5
View File
@@ -128,16 +128,16 @@ foreach(CXX_STANDARD 11 14 17 20 23 26)
COMMENT "Compile and test with Clang for C++${CXX_STANDARD}"
)
# pass -stdlib=libc++ through CXXFLAGS: an explicit -DCMAKE_CXX_FLAGS would make CMake ignore CXXFLAGS
add_custom_target(ci_test_clang_libcxx_cxx${CXX_STANDARD}
COMMAND CXX=${CLANG_TOOL} CXXFLAGS="${CLANG_CXXFLAGS}" ${CMAKE_COMMAND}
COMMAND CXX=${CLANG_TOOL} CXXFLAGS="${CLANG_CXXFLAGS};-stdlib=libc++" ${CMAKE_COMMAND}
-DCMAKE_BUILD_TYPE=Debug -GNinja
-DJSON_BuildTests=ON -DJSON_FastTests=ON
-DJSON_TestStandards=${CXX_STANDARD}
-DCMAKE_CXX_FLAGS="-stdlib=libc++"
-DCMAKE_EXE_LINKER_FLAGS="-lc++abi"
-S${PROJECT_SOURCE_DIR} -B${PROJECT_BINARY_DIR}/build_clang_cxx${CXX_STANDARD}
COMMAND ${CMAKE_COMMAND} --build ${PROJECT_BINARY_DIR}/build_clang_cxx${CXX_STANDARD}
COMMAND cd ${PROJECT_BINARY_DIR}/build_clang_cxx${CXX_STANDARD} && ${CMAKE_CTEST_COMMAND} --parallel ${N} --output-on-failure
-S${PROJECT_SOURCE_DIR} -B${PROJECT_BINARY_DIR}/build_clang_libcxx_cxx${CXX_STANDARD}
COMMAND ${CMAKE_COMMAND} --build ${PROJECT_BINARY_DIR}/build_clang_libcxx_cxx${CXX_STANDARD}
COMMAND cd ${PROJECT_BINARY_DIR}/build_clang_libcxx_cxx${CXX_STANDARD} && ${CMAKE_CTEST_COMMAND} --parallel ${N} --output-on-failure
COMMENT "Compile and test with Clang for C++${CXX_STANDARD} (libc++)"
)
endforeach()
+18
View File
@@ -7,4 +7,22 @@
// SPDX-License-Identifier: MIT
#define DOCTEST_CONFIG_IMPLEMENT_WITH_MAIN
// libc++ annotates std::mutex for Clang's thread safety analysis, so -Weverything
// reports -Wthread-safety-negative for the locks in doctest's reporters, which are
// only compiled in this file. __has_warning keeps older Clang versions from
// reporting an unknown warning group.
#if defined(__clang__) && defined(__has_warning)
#if __has_warning("-Wthread-safety-negative")
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wthread-safety-negative"
#endif
#endif
#include "doctest_compatibility.h"
#if defined(__clang__) && defined(__has_warning)
#if __has_warning("-Wthread-safety-negative")
#pragma clang diagnostic pop
#endif
#endif