In reply to @qu4pk4:matrix.org
I am having troubles building Java application with gradle2nix that needs sources from one of the submodules. The nix version is 2.42.2, which is after the .?submodules=1 being needed. I have read this https://github.com/NixOS/nix/pull/7862#issuecomment-1908577578 and what I think is going on is that the submodules aren't being needed by the flake directly and therefore aren't fetched (because they are fetched lazily). What is the canonical way to force them to evaluate?

Ah, it's the # missing... is this expected behaviour:

nix build '.?submodules=1' <- doesn't work
nix build '.?submodules=1#' <- works and invokes the default

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