Rembg package for python don't work when imported in a flake

[jptrzy]

It is my first time using nur repos, so I don't know, if the issue is on my side or not.

I tried importing nur.repos..hello-nur and everything worked fine,
but while importing nur.repos.nagy.python3Packages.rembg everything starts to fuck up.

flake.nix:

{
  description = "TODo";

  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixpkgs-unstable";
    flake-utils.url = "github:numtide/flake-utils";
    nur.url = "github:nix-community/NUR";
  };

  outputs = { self, nixpkgs, nur, flake-utils }: flake-utils.lib.eachDefaultSystem (system: let
    pkgs = import nixpkgs { inherit system; };

    nurPkgs = import nur {
      nurpkgs = pkgs;
      pkgs = pkgs;
    };

    pythonEnv = pkgs.python3.withPackages (ps: with ps; [
      nurPkgs.repos.nagy.python3Packages.rembg
    ]);
  in {
    devShell = pkgs.mkShell {
      packages = [
        nurPkgs.repos.mic92.hello-nur
        pythonEnv
      ];
    };
  });
}

Error message:

$ nix develop --show-trace
error:
       … while calling the 'derivationStrict' builtin
         at <nix/derivation-internal.nix>:9:12:
            8|
            9|   strict = derivationStrict drvAttrs;
             |            ^
           10|

       … while evaluating derivation 'nix-shell'
         whose name attribute is located at /nix/store/xd4806df52f1vhc7w614vqkffvw1763f-source/pkgs/stdenv/generic/make-derivation.nix:336:7

       … while evaluating attribute 'nativeBuildInputs' of derivation 'nix-shell'
         at /nix/store/xd4806df52f1vhc7w614vqkffvw1763f-source/pkgs/stdenv/generic/make-derivation.nix:380:7:
          379|       depsBuildBuild              = elemAt (elemAt dependencies 0) 0;
          380|       nativeBuildInputs           = elemAt (elemAt dependencies 0) 1;
             |       ^
          381|       depsBuildTarget             = elemAt (elemAt dependencies 0) 2;

       … while calling the 'getAttr' builtin
         at <nix/derivation-internal.nix>:19:19:
           18|       value = commonAttrs // {
           19|         outPath = builtins.getAttr outputName strict;
             |                   ^
           20|         drvPath = strict.drvPath;

       … while calling the 'derivationStrict' builtin
         at <nix/derivation-internal.nix>:9:12:
            8|
            9|   strict = derivationStrict drvAttrs;
             |            ^
           10|

       … while evaluating derivation 'python3-3.12.4-env'
         whose name attribute is located at /nix/store/xd4806df52f1vhc7w614vqkffvw1763f-source/pkgs/stdenv/generic/make-derivation.nix:336:7

       … while evaluating attribute 'passAsFile' of derivation 'python3-3.12.4-env'
         at /nix/store/xd4806df52f1vhc7w614vqkffvw1763f-source/pkgs/build-support/trivial-builders/default.nix:60:9:
           59|         inherit buildCommand name;
           60|         passAsFile = [ "buildCommand" ]
             |         ^
           61|           ++ (derivationArgs.passAsFile or [ ]);

       … while evaluating the attribute 'passAsFile'
         at /nix/store/xd4806df52f1vhc7w614vqkffvw1763f-source/pkgs/build-support/buildenv/default.nix:76:5:
           75|     # XXX: The size is somewhat arbitrary
           76|     passAsFile = if builtins.stringLength pkgs >= 128*1024 then [ "pkgs" ] else [ ];
             |     ^
           77|   }

       … while evaluating a branch condition
         at /nix/store/xd4806df52f1vhc7w614vqkffvw1763f-source/pkgs/build-support/buildenv/default.nix:76:18:
           75|     # XXX: The size is somewhat arbitrary
           76|     passAsFile = if builtins.stringLength pkgs >= 128*1024 then [ "pkgs" ] else [ ];
             |                  ^
           77|   }

       … in the argument of the not operator
         at /nix/store/xd4806df52f1vhc7w614vqkffvw1763f-source/pkgs/build-support/buildenv/default.nix:76:48:
           75|     # XXX: The size is somewhat arbitrary
           76|     passAsFile = if builtins.stringLength pkgs >= 128*1024 then [ "pkgs" ] else [ ];
             |                                                ^
           77|   }

       … while calling the 'lessThan' builtin
         at /nix/store/xd4806df52f1vhc7w614vqkffvw1763f-source/pkgs/build-support/buildenv/default.nix:76:48:
           75|     # XXX: The size is somewhat arbitrary
           76|     passAsFile = if builtins.stringLength pkgs >= 128*1024 then [ "pkgs" ] else [ ];
             |                                                ^
           77|   }

       … while calling the 'stringLength' builtin
         at /nix/store/xd4806df52f1vhc7w614vqkffvw1763f-source/pkgs/build-support/buildenv/default.nix:76:21:
           75|     # XXX: The size is somewhat arbitrary
           76|     passAsFile = if builtins.stringLength pkgs >= 128*1024 then [ "pkgs" ] else [ ];
             |                     ^
           77|   }

       … while calling the 'toJSON' builtin
         at /nix/store/xd4806df52f1vhc7w614vqkffvw1763f-source/pkgs/build-support/buildenv/default.nix:58:12:
           57|             nativeBuildInputs buildInputs;
           58|     pkgs = builtins.toJSON (map (drv: {
             |            ^
           59|       paths =

       … while calling the 'map' builtin
         at /nix/store/xd4806df52f1vhc7w614vqkffvw1763f-source/pkgs/build-support/buildenv/default.nix:58:29:
           57|             nativeBuildInputs buildInputs;
           58|     pkgs = builtins.toJSON (map (drv: {
             |                             ^
           59|       paths =

       … from call site
         at /nix/store/xd4806df52f1vhc7w614vqkffvw1763f-source/pkgs/development/interpreters/python/wrapper.nix:20:13:
           19|   env = let
           20|     paths = requiredPythonModules (extraLibs ++ [ python ] ) ;
             |             ^
           21|     pythonPath = "${placeholder "out"}/${python.sitePackages}";

       … while calling 'requiredPythonModules'
         at /nix/store/xd4806df52f1vhc7w614vqkffvw1763f-source/pkgs/development/interpreters/python/python-packages-base.nix:54:27:
           53|   # Get list of required Python modules given a list of derivations.
           54|   requiredPythonModules = drvs: let
             |                           ^
           55|     modules = lib.filter hasPythonModule drvs;

       … while calling the 'foldl'' builtin
         at /nix/store/xd4806df52f1vhc7w614vqkffvw1763f-source/pkgs/development/interpreters/python/python-packages-base.nix:56:6:
           55|     modules = lib.filter hasPythonModule drvs;
           56|   in lib.unique ([python] ++ modules ++ lib.concatLists (lib.catAttrs "requiredPythonModules" modules));
             |      ^
           57|

       … while calling the 'filter' builtin
         at /nix/store/xd4806df52f1vhc7w614vqkffvw1763f-source/pkgs/development/interpreters/python/python-packages-base.nix:55:15:
           54|   requiredPythonModules = drvs: let
           55|     modules = lib.filter hasPythonModule drvs;
             |               ^
           56|   in lib.unique ([python] ++ modules ++ lib.concatLists (lib.catAttrs "requiredPythonModules" modules));

       … while calling 'hasPythonModule'
         at /nix/store/xd4806df52f1vhc7w614vqkffvw1763f-source/pkgs/development/interpreters/python/python-packages-base.nix:51:21:
           50|   # Check whether a derivation provides a Python module.
           51|   hasPythonModule = drv: drv?pythonModule && drv.pythonModule == python;
             |                     ^
           52|

       … in the left operand of the AND (&&) operator
         at /nix/store/xd4806df52f1vhc7w614vqkffvw1763f-source/pkgs/development/interpreters/python/python-packages-base.nix:51:43:
           50|   # Check whether a derivation provides a Python module.
           51|   hasPythonModule = drv: drv?pythonModule && drv.pythonModule == python;
             |                                           ^
           52|

       … from call site
         at /nix/store/5ykifwh5m8232hcks74p8f7phjxdw0mb-source/flake.nix:24:7:
           23|     pythonEnv = pkgs.python3.withPackages (ps: with ps; [
           24|       nurPkgs.repos.nagy.python3Packages.rembg
             |       ^
           25|       # Add other Python packages here if needed

       … while calling 'createRepo'
         at /nix/store/qn9gxai1s6ib5lyfhayq6s7jyzq03dvf-source/default.nix:18:22:
           17|
           18|   createRepo = name: attr: import ./lib/evalRepo.nix {
             |                      ^
           19|     inherit name pkgs lib;

       … from call site
         at /nix/store/qn9gxai1s6ib5lyfhayq6s7jyzq03dvf-source/default.nix:18:28:
           17|
           18|   createRepo = name: attr: import ./lib/evalRepo.nix {
             |                            ^
           19|     inherit name pkgs lib;

       … while calling anonymous lambda
         at /nix/store/qn9gxai1s6ib5lyfhayq6s7jyzq03dvf-source/lib/evalRepo.nix:1:1:
            1| { name
             | ^
            2| , url

       … from call site
         at /nix/store/qn9gxai1s6ib5lyfhayq6s7jyzq03dvf-source/lib/evalRepo.nix:33:11:
           32|     might result in infinite recursion when used with NixOS modules.
           33|   '' else expr (builtins.intersectAttrs args passedArgs)
             |           ^
           34|

       … while calling anonymous lambda
         at /nix/store/jiixxaq1ihy0dzgp78i21gh17piy2h83-source/default.nix:1:1:
            1| {
             | ^
            2|   pkgs ? import <nixpkgs> { },

       … in the left operand of the update (//) operator
         at /nix/store/jiixxaq1ihy0dzgp78i21gh17piy2h83-source/default.nix:17:1:
           16| applied-overlay
           17| // {
             | ^
           18|

       … while calling the 'import' builtin
         at /nix/store/jiixxaq1ihy0dzgp78i21gh17piy2h83-source/default.nix:8:21:
            7| let
            8|   by-name-overlay = import <nixpkgs/pkgs/top-level/by-name-overlay.nix> ./pkgs/by-name;
             |                     ^
            9|   # this line allows packages to call themselves

       … while realising the context of a path

       … while calling the 'findFile' builtin
         at /nix/store/jiixxaq1ihy0dzgp78i21gh17piy2h83-source/default.nix:8:28:
            7| let
            8|   by-name-overlay = import <nixpkgs/pkgs/top-level/by-name-overlay.nix> ./pkgs/by-name;
             |                            ^
            9|   # this line allows packages to call themselves

       error: cannot look up '<nixpkgs/pkgs/top-level/by-name-overlay.nix>' in pure evaluation mode (use '--impure' to override)

[Pandapip1]

This is an issue with nagy's upstream: https://github.com/nagy/nur-packages/blob/6d4ca3a1f1725bbb9bbe921411e4221eaa97658a/default.nix#L8 is impure. For the time being, adding the --impure argument to your nix commands should work until it's fixed.