[BUG] tests fail for Clang CL

[mgovers]

Repro

cmake -DCMAKE_C_COMPILER="clang-cl.exe" -DCMAKE_CXX_COMPILER=clang-cl.exe "-DCMAKE_CXX_FLAGS=/DWIN32 /D_WINDOWS /W3 /WX /GR /EHsc -Wno-uninitialized-const-reference" -DCMAKE_BUILD_TYPE=RelWithDebInfo -S"." -B"cpp_build/clang-cl-release" -G Ninja  
cmake --build .\cpp_build\clang-cl-release\
.\cpp_build\clang-cl-debug\bin\power_grid_model_unit_tests.exe

Initial investigation

Likely related to this chunk of code not working:

template <class T>
struct trait_pointer_to_member;
template <class StructType, class ValueType>
struct trait_pointer_to_member<ValueType StructType::*> {
    using struct_type = StructType;
    using value_type = ValueType;
};

In get_data_attribute, I logged the related types for every field:

template <typename StructType, auto member_ptr>
inline DataAttribute get_data_attribute(std::string const& name) {
    using value_type = typename trait_pointer_to_member<StructType, decltype(member_ptr)>::value_type;
    using single_data_type = data_type<value_type>;
    std::cout << name << ": "
              << typeid(member_ptr).name() << " - "
              << typeid(value_type).name() << " - "
              << typeid(single_data_type).name() << " - "
              << single_data_type::numpy_type << std::endl;

    DataAttribute attr{};
    // [...]
    return attr;

and I saw that the types do not match at all with the fields, e.g.:

id: int power_grid_model::BaseUpdate::* __ptr64 - int - struct power_grid_model::meta_data::data_type<int,0> - i4
u_rated: double power_grid_model::VoltageSensorUpdate<0>::* __ptr64 - double - struct power_grid_model::meta_data::data_type<double,0> - f8

VoltageSensorUpdate does not contain any u_rated. The wrong pointer is matched with the wrong type, and as a result, the entire memory layout is wrong.

In addition, it is probably a good idea to add a static_assert<std::is_standard_layout_v<T>> for every input, update and output struct

Other notes

FYI: @nitbharambe found multiple bugs for the Clang CL presets (SEGFAULTs, type mismatch, ...). The compiler compiles the code, but the tests fail.

After investigating:

• I am able to repro on main, which means that it's not a problem on my branch
• we do need to disable the Clang CL presets for the time being.

Apparently, I did not find the issue before because I just so happened to not run the tests for these specific presets (I did do a matrix test with (gcc, clang, msvc) x (release, debug), but apparently not for clang-cl)

c.c. @TonyXiang8787 @petersalemink95

Originally posted by @mgovers in #239 (comment)