Consider not instantiating nixpkgs, use numtide/nixpkgs-unfree.

[kittywitch]

See https://zimbatm.com/notes/1000-instances-of-nixpkgs and https://discourse.nixos.org/t/1000-instances-of-nixpkgs/17347

https://github.com/fufexan/nix-gaming/blob/master/pkgs/default.nix#L16-L19

If you want to do this, please consider using https://github.com/numtide/nixpkgs-unfree instead of instantiating a new pkgs instance. Give https://github.com/numtide/nixpkgs-unfree/tree/main?tab=readme-ov-file#flake-usage a read. You can allow it to have nixpkgs.follows from another nixpkgs instance, allowing the user to choose the ref of nixpkgs without disabling the capacity for unfree software, while allowing for a reduction in evaluation time and memory usage.

[ccicnce113424]

nixpkgs-unfree also creates an instance of nixpkgs.

https://github.com/numtide/nixpkgs-unfree/blob/12d82a604d21a65df008bdb1515eecb96f9e55dc/flake.nix#L26

[kittywitch]

and that's fine because at least you can share those instantiations across everybody who uses nixpkgs AND nixpkgs-unfree via legacyPackages accessors, like flake-parts says to do? you can't do that with the current implementation.

in fact, you can go a step further and use nixpkgs-unfree as nixpkgs inputs themselves; thus allowing you to nixpkgs.legacyPackages with only a single overall instantiation. noting that nixpkgs also instantiates itself for legacyPackages (because how else would that work?)

(I have no clue why your post was marked as off-topic, seems on-topic to me :<)

[kittywitch]

See https://flake.parts/module-arguments.html#pkgs and its use of inputs.nixpkgs.legacyPackages.${system}.

[ccicnce113424]

Using flake-parts provides a simpler way to allow unfree packages. See my pull request.

[kittywitch]

Using flake-parts provides a simpler way to allow unfree packages. See my pull request.

I see you noticed the flaw in your own methodology

[kittywitch]

ugh, accidental closure, sorry

[kittywitch]

Also, overlayAttrs is kind of grody in the first place because an overlay is supposed to use final and prev, using config.packages means that you will be using your own instantiation or the nixpkgs (or nixpkgs-unfree) input instantiations within the overlay, which is... removing the real use of final or prev to begin with

[ccicnce113424]

https://github.com/hercules-ci/flake-parts/blob/2cccadc7357c0ba201788ae99c4dfa90728ef5e0/extras/easyOverlay.nix#L57

[ccicnce113424]

flake-parts' easyOverlay forces prev to be used as _module.args.pkgs. Therefore, using the overlay will not create a new Nixpkgs instance.

[kittywitch]

flake-parts' easyOverlay forces prev to be used as _module.args.pkgs. Therefore, using the overlay will not create a new Nixpkgs instance.

that part is ok then

[fufexan]

Sorry for not replying here earlier, I had a lot going on. Have you identified the best way to go forward with this?