Flox nixpkgs update interval

Developing with flox
1

(flox v0.2.0-r474) When flox developing a project I want to use packages from nixpkgs 22.11 channel with backports.

But flox tells me this:

...
• Updated input 'flox-floxpkgs/nixpkgs/nixpkgs':
    follows 'flox-floxpkgs/nixpkgs/nixpkgs-stable'
  → 'github:flox/nixpkgs/60c1d71f2ba4c80178ec84523c2ca0801522e0a6' (2023-03-19)
...

i.e. an older nixpkgs version that does not include specific backports. How can I let flox re-use the nixpkgs that my system uses? Should this be set in shells/<project>/default.nix and if so what is the recommended way?

1 Like
2

Right now I believe it’s necessary to use inline dependency declarations for anything that isn’t using the flox-floxpkgs/nixpkgs input. We have plans to improve this in the future, but this should work for you in the mean time:

$ flox edit -e my-env;
# Write your inline package like this.
# Replace that `rev' with whatever you'd like.
{
  inline.packages.terraform = { system, ... }: let
    nixpkgs = builtins.getFlake
                "github:NixOS/nixpkgs/f8f124009497b3f9908f395d2533a990feee1de8";
  in nixpkgs.legacyPackages.${system}.terraform;
}
3

Any time I think I grokked the *.nix, soon there comes something I want to do that does not fit quite right. I am using ./shells/test-project/default.nix with these contents:

{
  mkShell,
  stdenv,
  zlib,
  pkgs,
  llvmPackages_16,
}:
mkShell {
  nativeBuildInputs = with pkgs; [
    cmake
    gdb
    libxml2
    ninja
    qemu
    wasmtime
    zlib
  ] ++ (with llvmPackages_16; [
    clang
    clang-unwrapped
    lld
    llvm
  ]);

  hardeningDisable = [ "all" ];

  shellHook = ''
    echo "setting shell hooks to include zig compiled from source"
    ...
  '';
}

so how would I use your snippet with that?

edit: I am using .envrc with flox (. <(flox print-dev-env)) and when I cd-ed into the project dir just now it updated nixpkgs automatically…

...
warning: not writing modified lock file of flake 'git+file:///home/fps/dev/ziglings':
• Updated input 'flox-floxpkgs/nixpkgs/nixpkgs':
    follows 'flox-floxpkgs/nixpkgs/nixpkgs-stable'
  → 'github:flox/nixpkgs/7084250df3d7f9735087d3234407f3c1fc2400e3' (2023-05-22)
...

So it works now, I don’t know why it did not update last time I tried.