`error: cannot coerce null to a string` on M1 Mac

[n8henrie]

mach-nix gen -r <(echo "simplenet==0.1.2") works as expected on Linux x86_64 machine.

On MacOS 12.4 (M1 MBP) I'm having trouble. The flake doesn't seem to give me a binary at all (https://github.com/DavHau/mach-nix/issues/479).

Using a pip installed mach-nix:

$ mach-nix gen -r <(echo "simplenet==0.1.2")
Generating python environment... If you run this the first time, the python package index and dependency graph (~200MB) need to be downloaded. Please stay patient!
error: cannot coerce null to a string

       at /nix/store/lhjdy3fdhglnc3p4sv5hra11v1mch0gs-nixpkgs/pkgs/stdenv/generic/make-derivation.nix:192:34:

          191|         // (lib.optionalAttrs (!(attrs ? name) && attrs ? pname && attrs ? version)) {
          192|           name = "${attrs.pname}-${attrs.version}";
             |                                  ^
          193|         } // (lib.optionalAttrs (stdenv.hostPlatform != stdenv.buildPlatform && !dontAddHostSuffix && (attrs ? name || (attrs ? pname && attrs ? version)))) {
(use '--show-trace' to show detailed location information)

Using a nix-shell installed mach-nix:

[nix-shell:/tmp/foo]$ mach-nix gen -r <(printf "simplenet==0.1.2")
path is '/nix/store/ahaz90hy6lins0a56mdivrd2fjj3rcb5-554d2d8aa25b6e583575459c297ec23750adb6cb'
error: the string '{
         "nodes": {
           "flake-utils": {
             "locked": {
               "lastModified": 1642700792,
               "narHash": "sha256-XqHrk7hFb+zBvRg6Ghl+AZDq03ov6OshJLiSWOoX5es=",
               "owner": "numtide",
               "repo": "flake-utils",
               "rev": "846b2ae0fc4cc943637d3d1def4454213e203cba",
               "type": "github"
             },
             "original": {
               "owner": "numtide",
               "repo": "flake-utils",
               "type": "github"
             }
           },
           "nixpkgs": {
             "locked": {
               "lastModified": 1643805626,
               "narHash": "sha256-AXLDVMG+UaAGsGSpOtQHPIKB+IZ0KSd9WS77aanGzgc=",
               "owner": "NixOS",
               "repo": "nixpkgs",
               "rev": "554d2d8aa25b6e583575459c297ec23750adb6cb",
               "type": "github"
             },
             "original": {
               "id": "nixpkgs",
               "ref": "nixos-unstable",
               "type": "indirect"
             }
           },
           "pypi-deps-db": {
             "flake": false,
             "locked": {
               "lastModified": 1643877077,
               "narHash": "sha256-jv8pIvRFTP919GybOxXE5TfOkrjTbdo9QiCO1TD3ZaY=",
               "owner": "DavHau",
               "repo": "pypi-deps-db",
               "rev": "da53397f0b782b0b18deb72ef8e0fb5aa7c98aa3",
               "type": "github"
             },
             "original": {
               "owner": "DavHau",
               "repo": "pypi-deps-db",
               "type": "github"
             }
           },
           "root": {
             "inputs": {
               "flake-utils": "flake-utils",
               "nixpkgs": "nixpkgs",
               "pypi-deps-db": "pypi-deps-db"
             }
           }
         },
         "root": "root",
         "version": 7
       }
       ' is not allowed to refer to a store path (such as '')

       at /nix/store/gsz7mwqjjhvhg5dq2g9xmz5rw590mms6-mach-nix-master/lib/python3.9/site-packages/mach_nix/nix/flake-inputs.nix:4:11:

            3| let
            4|   lock = (fromJSON (readFile ../flake.lock)).nodes;
             |           ^
            5|   get = input: {
(use '--show-trace' to show detailed location information)

Any idea why this wouldn't work on MacOS?