fmt::runtime required now?

[Zitrax]

When I moved to clang 20 and spdlog 1.15.2 I am getting compile errors like:

 error: call to consteval function 'fmt::basic_format_string<char, const char *, const char *&, int &>::basic_format_string<FMT_COMPILE_STRING, 0>' is not a constant expression

and I read that you now have to wrap logging in fmt::runtime to avoid that like so:

spdlog::info(fmt::runtime("{:d}"), "I am not a number");

and it does seem to work. But am I getting this right that this is a requirement now? A lot of my logging takes runtime arguments so it gets so verbose now. I can write some wrappers - but maybe there are better alternatives that I missed?

[gabime]

I think this should be asked in the fmt repo. I hope they have a solution for this

[Zitrax]

Looking further it seem to have been some incompatibility in vcpkg. When using spdlog in vcpkg it builds with SPDLOG_FMT_EXTERNAL=ON and uses its own fmt instead of the bundled one. However latest spdlog in vcpkg is 1.15.2 while fmt is on 11.0.2. Th at combination does apparently not work. I added an overlay port to force fmt to the latest 11.1.4 and then it compiles fine without adding fmt::runtime.

[Zitrax]

microsoft/vcpkg#42936 will solve the issue.

[gabime]

That explains it. Thanks for investigating