Package build broken when using flakes

[emilazy]

I'm not sure whether this is an issue with nixpkgs-fmt or an upstream https://github.com/nix-community/fenix issue, but since I don't understand it I figured I'd report here and let people who have actually used fenix figure out what's up :)

I'm also not sure whether this is Darwin-specific or not.

emily@yuyuko ~/nixpkgs-fmt-test> cat flake.nix
{
  inputs.nixpkgs-fmt.url = "github:nix-community/nixpkgs-fmt";
  # work around https://github.com/NixOS/nix/pull/4641
  inputs.naersk.url = "github:nmattia/naersk";

  outputs = { self, nixpkgs, nixpkgs-fmt, naersk }: {
    devShell."x86_64-darwin" = nixpkgs.legacyPackages."x86_64-darwin".mkShell {
      buildInputs = [ nixpkgs-fmt.defaultPackage."x86_64-darwin" ];
    };
  };
}
emily@yuyuko ~/nixpkgs-fmt-test> nix develop
error: in pure evaluation mode, 'fetchTarball' requires a 'sha256' argument

       … while evaluating the file '/nix/store/d28xpy5rjhvy20p0dfdbvl68way34yg0-source/packages.nix':

       … while evaluating anonymous lambda

       at /nix/store/d28xpy5rjhvy20p0dfdbvl68way34yg0-source/default.nix:1:27:

            1| import ./lib/overlay.nix (_: import ./packages.nix)
             |                           ^

       … from call site

       at /nix/store/d28xpy5rjhvy20p0dfdbvl68way34yg0-source/lib/overlay.nix:2:13:

            1| f: _: super:
            2| let fenix = f super;
             |             ^
            3| in {

       … while evaluating the attribute 'fenix'

       at /nix/store/d28xpy5rjhvy20p0dfdbvl68way34yg0-source/lib/overlay.nix:4:10:

            3| in {
            4|   inherit fenix;
             |          ^
            5|   rust-analyzer-nightly = fenix.rust-analyzer;

       … while evaluating the attribute 'RUSTC' of the derivation 'nixpkgs-fmt-1.2.0'

       at /nix/store/pkdq86iai1j0azkvhya33ldj0bvjqp9z-source/pkgs/stdenv/generic/make-derivation.nix:201:11:

          200|         // (lib.optionalAttrs (attrs ? name || (attrs ? pname && attrs ? version)) {
          201|           name =
             |           ^
          202|             let

       … while evaluating the attribute 'buildInputs' of the derivation 'nix-shell'

       at /nix/store/y0s7h01713aa0zm22xw4xq3dl7ajjx4j-source/pkgs/stdenv/generic/make-derivation.nix:201:11:

          200|         // (lib.optionalAttrs (attrs ? name || (attrs ? pname && attrs ? version)) {
          201|           name =
             |           ^
          202|             let

[zimbatm]

thanks for the report, I need to fix this. The last released version of the project should still be working fine if you are looking for a working version in the meantime.

[tnytown]

Ran into this issue while trying to poking at #257. I think (?) this is a fenix issue, tracing the error leads me here.
Evidently, flake-compat isn't fetched with a hash, so flake evaluation fails. nix-community/fenix#28 should fix it, as it eliminates that problematic usage of fetchTarball.