clang 20.1 warnings

[terpstra]

Apparently glaze is using c++26 in exactly one place:

In file included from glaze/include/glaze/json.hpp:20:
glaze/include/glaze/json/schema.hpp:577:24: warning: 'static_assert' with a user-generated message is a C++26 extension [-Wc++26-extensions]
  577 |                        join_v<chars<"Slash in name: \"">, ref, chars<"\" in json schema references is not allowed">>);
      |                        ^

There are also 115 warnings related to "-Wmissing-braces"; for example:

glaze/include/glaze/json/schema.hpp:135:47: warning: suggest braces around initialization of subobject [-Wmissing-braces]
  135 |                                               &T::minimum, //
      |                                               ^~~~~~~~~~~
      |                                               {          }

[stephenberry]

Thanks for pointing these out. Will try to address soon.

In the past there were clang bugs with Wmissing-braces, so it's always been disabled for Clang development. But, I'll turn it on to try to remove at least most of the warnings. Because we treat warnings as errors we can't generally use this flag.

[stephenberry]

@terpstra, I fixed the warning for the C++26 usage (now checks __cplusplus macro, before it only checked for compiler support for the feature). It wasn't really an issue because it would only give you better diagnostics when the feature was supported, but now you won't get an annoying warning.

I dug more into Wmissing-braces. In my opinion this warning is broken on Clang. Even when there is a valid deduction guide (such as with glz::tuple) the compiler emits warnings. The solution is to use a make_tuple function. However, this is bad, because it increases compilation times versus the initializer list construction with the deduction guide. This compilation performance is significant.

I could scatter macros all throughout the code to push and pop Wmissing-braces diagnostics, but this feels wrong. I feel this is something that Clang should be encouraged to fix.

Note, if you use CMake and use the glaze::glaze target, then you'll get Wno-missing-braces and won't get any warnings.

What are your thoughts?

[terpstra]

I appreciate the c++26 fix, thanks.

I don't have an opinion one way or the other wrt. Wmissing-braces. If you think it's a clang issue, though, you should file an issue against their project. Short-term, we're just using -Wno-missing-braces in our tool now, to match glaze's CMake rules.

[stephenberry]

I'm going to move this to discussions. I don't have time to submit a detailed report to the Clang team, but there is already a lot of discussion about missing braces warnings online and I'm sure the Clang team is aware of some of the issues.

[samkellett]

I know it's a pain because it's clang's fault and not yours but I think that using push and pop diagnostics in your library is the correct solution because otherwise the user of the library is required to then have to always use -Wno-missing-braces with your library (we use Glaze through Bazel so we don't get the free propagation that your cmake target delivers).

[pps83]

imo, it's best to add to some top level glaze header like glaze.hpp to simply

#ifdef __clang__
#pragma clang diagnostic push
#pragma clang diagnostic ignored "-Wmissing-braces"
#endif

#include "glaze/base64/base64.hpp"
...
#include "glaze/util/key_transformers.hpp"

#ifdef __clang__
#pragma clang diagnostic pop
#endif

I don't use any of the cmake files that come with glaze and I had gazilion warnings/errors first try when I tried to use it.
the project is just great, should be part of std lib

[samkellett]

We're applying this patch internally to fix all the warnings:

diff --git a/include/glaze/json/schema.hpp b/include/glaze/json/schema.hpp
index 74e97ab5..9475d411 100644
--- a/include/glaze/json/schema.hpp
+++ b/include/glaze/json/schema.hpp
@@ -119,6 +119,8 @@ namespace glz
                                           "ExtUnits", //
                                           "ExtAdvanced"};
 
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wmissing-braces"
          static constexpr glz::tuple value = {&T::ref, //
                                               &T::title, //
                                               &T::description, //
@@ -150,6 +152,7 @@ namespace glz
                                               &T::ExtUnits, //
                                               &T::ExtAdvanced};
       };
+#pragma clang diagnostic pop
    };
 
    namespace detail

Happy to make a PR of this to upstream it if that is desirable?

[pps83]

should be merged into master to avoid maintaining updated versions

[stephenberry]

Just merged in #2024, which adds these warning blockers for Clang. Thanks for the feedback!

[stephenberry]

Just merged in #2024, which adds "-Wmissing-braces" for tuple brace initialization that would create warnings.

[pps83]

Just merged in #2024, which adds "-Wmissing-braces" for tuple brace initialization that would create warnings.

this didn't fix it.
Still tons of clang-cl warnings when I reverted my local fix up

2>In file included from ..\src\PolygonTest.cpp:13:
2>In file included from D:\glaze\include\glaze/glaze.hpp:36:
2>In file included from D:\glaze\include\glaze/beve.hpp:7:
2>In file included from D:\glaze\include\glaze/beve/ptr.hpp:6:
2>In file included from D:\glaze\include\glaze/beve/read.hpp:7:
2>In file included from D:\glaze\include\glaze/beve/key_traits.hpp:7:
2>In file included from D:\glaze\include\glaze/core/common.hpp:16:
2>In file included from D:\glaze\include\glaze/core/cast.hpp:8:
2>D:\glaze\include\glaze/tuplet/tuple.hpp(437,15): warning : suggest braces around initialization of subobject [-Wmissing-braces]
2>D:\glaze\include\glaze/tuplet/tuple.hpp(437,15): warning : suggest braces around initialization of subobject [-Wmissing-braces]
2>D:\glaze\include\glaze/tuplet/tuple.hpp(437,15): warning : suggest braces around initialization of subobject [-Wmissing-braces]
2>D:\glaze\include\glaze/tuplet/tuple.hpp(437,15): warning : suggest braces around initialization of subobject [-Wmissing-braces]
2>D:\glaze\include\glaze/tuplet/tuple.hpp(437,15): warning : suggest braces around initialization of subobject [-Wmissing-braces]
2>D:\glaze\include\glaze/tuplet/tuple.hpp(437,15): warning : suggest braces around initialization of subobject [-Wmissing-braces]
2>D:\glaze\include\glaze/tuplet/tuple.hpp(437,15): warning : suggest braces around initialization of subobject [-Wmissing-braces]
2>D:\glaze\include\glaze/reflection/to_tuple.hpp(93,22): message : in instantiation of function template specialization 'glz::tie<const double, const double, const double, const double, const double, const unsigned int, const double>' requested here
2>D:\glaze\include\glaze/reflection/to_tuple.hpp(1280,27): message : in instantiation of function template specialization 'glz::to_tie<const AggregateBar1 &, 7ULL>' requested here
2>D:\glaze\include\glaze/reflection/get_name.hpp(49,60): message : in instantiation of function template specialization 'glz::detail::get_ptr<0ULL, const AggregateBar1 &>' requested here
2>D:\glaze\include\glaze/reflection/get_name.hpp(88,44): message : in instantiation of variable template specialization 'glz::detail::get_name_impl<0ULL, AggregateBar1>' requested here
2>D:\glaze\include\glaze/reflection/get_name.hpp(97,66): message : in instantiation of template class 'glz::member_nameof_impl<0ULL, AggregateBar1>' requested here
2>D:\glaze\include\glaze/reflection/get_name.hpp(97,57): message : (skipping 5 contexts in backtrace; use -ftemplate-backtrace-limit=0 to see all)
2>D:\glaze\include\glaze/json/read.hpp(2156,46): message : in instantiation of template class 'glz::reflect<AggregateBar1>' requested here
2>D:\glaze\include\glaze/json/read.hpp(55,37): message : in instantiation of function template specialization 'glz::from<10, AggregateBar1>::op<glz::opts{10, true, false, false, true, false, false, 32, 3, true, false, false, false, false, false, false, false, false, false, false, 0}, string_literal<1>{""}, AggregateBar1 &, glz::context &, const char *&, const char *&>' requested here
2>D:\glaze\include\glaze/core/read.hpp(63,39): message : in instantiation of function template specialization 'glz::parse<10>::op<glz::opts{10, true, false, false, true, false, false, 32, 3, true, false, false, false, false, false, false, false, false, false, false, 0}, AggregateBar1 &, glz::context &, const char *&, const char *&>' requested here
2>D:\glaze\include\glaze/core/read.hpp(114,14): message : in instantiation of function template specialization 'glz::read<glz::opts{10, true, false, false, true, false, false, 32, 3, true, false, false, false, false, false, false, false, false, false, false, 0}, AggregateBar1, std::basic_string_view<char> &, glz::context &>' requested here
2>..\src\PolygonTest.cpp(374,33): message : in instantiation of function template specialization 'glz::read<glz::opts{10, true, false, false, true, false, false, 32, 3, true, false, false, false, false, false, false, false, false, false, false, 0}, AggregateBar1, std::basic_string_view<char> &>' requested here

[pps83]

this fixes it #2043