python3Packages.bitsandbytes: fix cuda build

[GaetanLepage]

Things done

Since the latest staging-next PR was merged into master, glibc was updated from 2.40 to 2.42.
Some maths functions (cospi, sinpi, ...) now have noexcept(true) in their declarations.
However, CUDA's crt/math_functions.h declares the same functions without matching exception specs.
Hence, we get such errors during the cmake configure step:

-- Configuring bitsandbytes (Backend: cuda)
CMake Error at /nix/store/lxkvigfj5xy6w2bs7h4xwr3d7wb7piqb-cmake-4.1.2/share/cmake-4.1/Modules/CMakeDetermineCompilerId.cmake:928 (message):
  Compiling the CUDA compiler identification source file
  "CMakeCUDACompilerId.cu" failed.

  Compiler:
  /nix/store/k3dps7npc4mb3k1dd2ksfkhfpdmg5i1k-cuda12.8-cuda_nvcc-12.8.93/bin/nvcc

  Build flags:

  Id flags:
  --keep;--keep-dir;tmp;-ccbin=/nix/store/aygjy2g4372sx18khagd07d7ir1dwxs4-gcc-wrapper-14.3.0/bin/c++
  -v

...

  /nix/store/rwalsamz4246k8f1zzxa54qx7w3fbzdg-glibc-2.42-47-dev/include/bits/mathcalls.h(83):
  error: exception specification is incompatible with that of previous
  function "cospi" (declared at line 2601 of
  /nix/store/w2657dnk2y6970ph0fqkyr0x7j34m7kf-cuda-native-redist-12.8/include/crt/math_functions.h)

     extern double cospi (double __x) noexcept (true); extern double __cospi (double __x) noexcept (true);

...

  6 errors detected in the compilation of "CMakeCUDACompilerId.cu".

  # --error 0x2 --





Call Stack (most recent call first):
  /nix/store/lxkvigfj5xy6w2bs7h4xwr3d7wb7piqb-cmake-4.1.2/share/cmake-4.1/Modules/CMakeDetermineCompilerId.cmake:8 (CMAKE_DETERMINE_COMPILER_ID_BUILD)
  /nix/store/lxkvigfj5xy6w2bs7h4xwr3d7wb7piqb-cmake-4.1.2/share/cmake-4.1/Modules/CMakeDetermineCompilerId.cmake:53 (__determine_compiler_id_test)
  /nix/store/lxkvigfj5xy6w2bs7h4xwr3d7wb7piqb-cmake-4.1.2/share/cmake-4.1/Modules/CMakeDetermineCUDACompiler.cmake:162 (CMAKE_DETERMINE_COMPILER_ID)
  CMakeLists.txt:105 (enable_language)


-- Configuring incomplete, errors occurred!

cc @NixOS/cuda-maintainers @kirillrdy @bcdarwin @06kellyjac

• Built on platform:
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• Tested, as applicable:
  • NixOS tests in nixos/tests.
  • Package tests at passthru.tests.
  • Tests in lib/tests or pkgs/test for functions and "core" functionality.
• Ran nixpkgs-review on this PR. See nixpkgs-review usage.
• Tested basic functionality of all binary files, usually in ./result/bin/.
• Nixpkgs Release Notes
  • Package update: when the change is major or breaking.
• NixOS Release Notes
  • Module addition: when adding a new NixOS module.
  • Module update: when the change is significant.
• Fits CONTRIBUTING.md, pkgs/README.md, maintainers/README.md and other READMEs.

[kirillrdy]

i got it working by patching cuda

       cuda_nvcc = prevCuda.cuda_nvcc.overrideAttrs (old: {
          postInstall = (old.postInstall or "") + ''
            for f in $(find $out -name math_functions.h); do
              sed -i -E "s/(\b(sinpi|cospi|rsqrt)\s*\(\s*double\s*x\s*\))\s*;/\1 noexcept (true);/g" "$f"
              sed -i -E "s/(\b(sinpi|cospi|rsqrt)f\s*\(\s*float\s*x\s*\))\s*;/\1 noexcept (true);/g" "$f"
            done
          '';
        });
        cuda_crt = if prevCuda ? cuda_crt then prevCuda.cuda_crt.overrideAttrs (old: {
          postInstall = (old.postInstall or "") + ''
            for f in $(find $out -name math_functions.h); do
              sed -i -E "s/(\b(sinpi|cospi|rsqrt)\s*\(\s*double\s*x\s*\))\s*;/\1 noexcept (true);/g" "$f"
              sed -i -E "s/(\b(sinpi|cospi|rsqrt)f\s*\(\s*float\s*x\s*\))\s*;/\1 noexcept (true);/g" "$f"
            done
          '';

maybe there are upstream fixes ?

[ConnorBaker]

You had to patch both cuda_nvcc and cuda_crt? It’s good to know about this though since I’ll probably have to patch a bunch of stuff in cuda-legacy 🫩

[kirillrdy]

actually for python3Packages.bitsandbytes you only need to patch cuda_nvcc, cuda_crt was needed for something else in my env