using example from README does not work with gtest and clang++17

[maldag]

I'm trying to integrate the glaze library into the project using CMake.
Upon writing an unit testcase with GTest and clang++17 using -std=c++20, I'm facing the following error:

/project/build_gtest/_deps/glaze-src/include/glaze/util/parse.hpp:165:31: error: call to consteval function 'glz::detail::repeat_byte' is not a constant expression [clang-diagnostic-error]
      return has_zero(chunk ^ repeat_byte(Char));
                              ^
/project/build_gtest/_deps/glaze-src/include/glaze/util/parse.hpp:165:43: note: subexpression not valid in a constant expression
      return has_zero(chunk ^ repeat_byte(Char));

The testcode is:

#include <gtest/gtest.h>
#include <string>

#include "glaze/glaze.hpp"

struct my_struct
{
  int i = 287;
  double d = 3.14;
  std::string hello = "Hello World";
  std::array<uint64_t, 3> arr = { 1, 2, 3 };
  std::map<std::string, int> map{{"one", 1}, {"two", 2}};
};


TEST(glaze_test,test1){
    my_struct s{};
    std::string buffer = glz::write_json(s); 
    EXPECT_STREQ(buffer,R"({
        "i": 287,
        "d": 3.14,
        "hello": "Hello World",
        "arr": [
            1,
            2,
            3
        ],
        "map": {
            "one": 1,
            "two": 2
        }
        })"
    );
}

Am I missing something here?

[stephenberry]

That is very strange. Looks like a bug in Clang 17, unless something else weird is going on with your setup.

I'll build with Clang 17 and get back to you soon.

[stephenberry]

I just built using Clang 17. Can you try building in another environment?

[maldag]

Which compiler arguments did you add to clang++-17? I used -std=c++20

[stephenberry]

-std=c++20 or -std=c++23 should both work

[stephenberry]

@maldag, here is an example of it building in compiler explorer with clang17: https://gcc.godbolt.org/z/zon9Mjjh9

[maldag]

I double checked my environment. Sorry for the noise, I was using and older version of clang-tidy in the buildprocess which caused the failing.

[stephenberry]

No problem, thanks for explaining the issue.