Example of adding a local package to be recognised by home-manager build is missing

[dietmarw-se]

I was following this nice starter config and was especially interested in the ability to define local packages under pkgs/. However I can't get home-manager build succeed because it always complains about my local package being unknown.

Example:

I have my package defined under:

├── pkgs
│   ├── mypkg
│   │   └── default.nix
│   └── default.nix

with all the other configuration taken from the standard example simply adding
home.packages = with pkgs; [ mypkg ]; as suggested in

nix-starter-configs/standard/home-manager/home.nix

Line 58 in 972935c

# home.packages = with pkgs; [ steam ];

is not enough since home-manger build will complain with
error: undefined variable 'mypkg'

Doing a nix build .#mypkg works fine though.

So how should one add the mypkg in order that it will be found by home-manager build?

[rykugur]

I was having this same problem and found a post from @Misterio77 in another issue. TLDR: in my configuration/home files, I added nixpkgs.overlays. = [ outputs.overlays.additions ]; and was then able to import my custom packages.

Relevant files in my config:

https://github.com/rykugur/dotfiles/blob/master/overlays/default.nix#L4
https://github.com/rykugur/dotfiles/blob/master/home/dusty/taln/home.nix#L30
https://github.com/rykugur/dotfiles/blob/master/home/dusty/taln/home.nix#L80 (importing my custom derivation)

[dietmarw-se]

@rykugur Thanks, this is interesting. I did have that line https://github.com/Misterio77/nix-starter-configs/blob/main/standard/home-manager/home.nix#L27 ( and the following two) commented out since I though I did not use overlays. I got it work with some help from the forum by addressing the usage of the package with

 # local packages
    inputs.self.packages.${system}.mypkg

instead of simply:

mypkg

Doing it like you did in your config as suggested in the three places will lead to the error message error: attribute 'outputs' missing in my case. Which I think lead me into the rabbit hole to get this working in the first place.
Anyway despite me having gotten it to work it would still be nice to have a working example demonstrated here in the nix-starter-config.
I think this is the challenge of nix that there are always multiple ways to get something done and for beginners this can cause some (nix) anxiety ;-)

[Misterio77]

Hey! You probably figured this out, but inputs.self == outputs, and the error is probably fixable by:

• Making sure you have outputs here: https://github.com/Misterio77/nix-starter-configs/blob/main/standard/home-manager/home.nix#L5
• If using hm as nixos module:
  • Make sure you're passing outputs like this: https://github.com/Misterio77/nix-starter-configs/blob/main/README.md?plain=1#L127
• If using hm standalone:
  • Make sure you're passing outputs like this: https://github.com/Misterio77/nix-starter-configs/blob/main/standard/flake.nix#L71