nixpkgs.config.allowUnfree not working for for unstable in users.users.user-name.packages

[mudrii]

Describe the bug

I have defined 2 channels in /root/.nix-channels

https://nixos.org/channels/nixos-19.09 nixos
https://nixos.org/channels/nixos-unstable unstable

in my configuration.nix I have

let
  unstable = import <unstable> {};
in
{
  nixpkgs.config.allowUnfree = true; 
  users = {
    mutableUsers = false;
    users.user-name = {
      isNormalUser = true;
      home = "/home/user-name";
      shell = "/run/current-system/sw/bin/fish";
      extraGroups = [ "wheel" "docker" "audio" "video" "networkmanager" ];
      hashedPassword = "$6$XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX";
      packages = with pkgs; [
        name-package
        unstable.name-package
      ];
    };
  };
environment.systemPackages = with pkgs; [
  name-package
  unstable.name-package
  ];
}

if name-package is Unfree package I am getting the error during

nixos-rebuild switch --upgrade                                                                                               
unpacking channels...
building Nix...
building the system configuration...
error: Package ‘xmind-8-update8’ in /nix/store/dzf50lqjswbm33gh48hxw0bqdqai1pkl-unstable-20.03pre193781.d484f2b7fc0/unstable/pkgs/applications/misc/xmind/default.nix:72 has an unfree license (‘unfree’), refusing to evaluate.

a) For `nixos-rebuild` you can set
  { nixpkgs.config.allowUnfree = true; }
in configuration.nix to override this.

b) For `nix-env`, `nix-build`, `nix-shell` or any other Nix command you can add
  { allowUnfree = true; }
to ~/.config/nixpkgs/config.nix.

(use '--show-trace' to show detailed location information)

error is for both users.users.user-name.packages and environment.systemPackages

If I do replace

let
  unstable = import <unstable> {};
in

with

let
  unstableTarball =
    fetchTarball
      https://github.com/NixOS/nixpkgs-channels/archive/nixos-unstable.tar.gz;
in
{
  nixpkgs.config = {
    packageOverrides = pkgs: {
      unstable = import unstableTarball {
        config = config.nixpkgs.config;
      };
    };
  };

The package is installed without an issue

To Reproduce
Follow the above configuration changes

Expected behavior
Package Unfree should be deployed using both methods.

Metadata

 - system: `"x86_64-linux"`
 - host os: `Linux 5.3.0, NixOS, 19.09beta317.88f32cca5a4 (Loris)`
 - multi-user?: `yes`
 - sandbox: `yes`
 - version: `nix-env (Nix) 2.3`
 - channels(root): `"nixos-19.09beta317.88f32cca5a4, unstable-20.03pre193781.d484f2b7fc0"`
 - nixpkgs: `/nix/var/nix/profiles/per-user/root/channels/nixos`

Above method is based on a tutorial from
https://functor.tokyo/blog/2018-02-18-install-packages-from-nixos-unstable

[alexarice]

I think you need

unstable = import <unstable> { config.allowUnfree = true; };

[alexarice]

Don't think this is a bug. nixpkgs.config refers to the config for only the nixos channel I believe.

[mudrii]

@alexarice Thx for the solution I didn't realize the option is not applied to nixos unstable looking back seems obvious. Would make more sense to see apply to unstable as well.

[alexarice]

import can work on any nix file. I don't really see why it should be expected to notice that the thing you have imported is a version of nixpkgs and pass the config in because of it