I am seeing a peculiar issue: nix build works just fine but when using the flake from my NixOS config I get complaints about Rust version:

error: builder for '/nix/store/p7dajki1blbc0wlsjk86ymh3pi3zh0mk-oblichey-0.0.1.drv' failed with exit code 101;
       last 10 log lines:
       > Finished cargoSetupPostPatchHook
       > Running phase: updateAutotoolsGnuConfigScriptsPhase
       > Running phase: configurePhase
       > Running phase: buildPhase
       > Executing cargoBuildHook
       > ++ env CC_X86_64_UNKNOWN_LINUX_GNU=/nix/store/9bv7dcvmfcjnmg5mnqwqlq2wxfn8d7yi-gcc-wrapper-13.2.0/bin/cc CXX_X86_64_UNKNOWN_LINUX_GNU=/nix/store/9bv7dcvmfcjnmg5mnqw
qlq2wxfn8d7yi-gcc-wrapper-13.2.0/bin/c++ CARGO_TARGET_X86_64_UNKNOWN_LINUX_GNU_LINKER=/nix/store/9bv7dcvmfcjnmg5mnqwqlq2wxfn8d7yi-gcc-wrapper-13.2.0/bin/cc CC_X86_64_UNKNOWN
_LINUX_GNU=/nix/store/9bv7dcvmfcjnmg5mnqwqlq2wxfn8d7yi-gcc-wrapper-13.2.0/bin/cc CXX_X86_64_UNKNOWN_LINUX_GNU=/nix/store/9bv7dcvmfcjnmg5mnqwqlq2wxfn8d7yi-gcc-wrapper-13.2.0/
bin/c++ CARGO_TARGET_X86_64_UNKNOWN_LINUX_GNU_LINKER=/nix/store/9bv7dcvmfcjnmg5mnqwqlq2wxfn8d7yi-gcc-wrapper-13.2.0/bin/cc CARGO_BUILD_TARGET=x86_64-unknown-linux-gnu HOST_C
C=/nix/store/9bv7dcvmfcjnmg5mnqwqlq2wxfn8d7yi-gcc-wrapper-13.2.0/bin/cc HOST_CXX=/nix/store/9bv7dcvmfcjnmg5mnqwqlq2wxfn8d7yi-gcc-wrapper-13.2.0/bin/c++ cargo build -j 8 --ta
rget x86_64-unknown-linux-gnu --frozen --profile release
       > error: package `cubecl v0.1.1 (https://github.com/tracel-ai/cubecl?rev=dd274b6515f853ab1c82db410d6fc7697060f69e#dd274b65)` cannot be built because it requires rustc
 1.79 or newer, while the currently active rustc version is 1.77.2
       > Either upgrade to rustc 1.79 or newer, or use
       > cargo update cubecl@0.1.1 --precise ver
       > where `ver` is the latest version of `cubecl` supporting rustc 1.77.2
       For full logs, run 'nix log /nix/store/p7dajki1blbc0wlsjk86ymh3pi3zh0mk-oblichey-0.0.1.drv'.
error: 1 dependencies of derivation '/nix/store/mxwvym1s7dd4szzs3ccxnwxfx4iqsqbb-ags.pam.drv' failed to build
error: 1 dependencies of derivation '/nix/store/fbzf0cszdcds4h93m52w7sicav68cfa0-etc.drv' failed to build
error: 1 dependencies of derivation '/nix/store/8s9wxgvic20f6pxp5cr6nmii9y25pirl-nixos-system-Simon-s-Tuxedo-InfinityBook-14-Gen8-24.11.20240529.ad57eef.drv' failed to build

Has anyone ever seen this?

(originally posted elsewhere but this room might be more appropriate)

In reply to @lxsameer:matrix.org
hey folks, do you know any solution to conditional flake inputs?

In reply to @simon.brandner:envs.net
This seems to contain some suggestions: https://nixos-and-flakes.thiscute.world/other-usage-of-flakes/inputs

In reply to@asmundesen:matrix.org
fzuplock.py