Fix delay with unfree package set

[llakala]

Currently, my custom nixpkgs instance has one big con: running anything has a three-second delay where it says Copying '/nix/store/HASHCONTENTS-nixpkgs-configured. This doesn't happen when I comment out the key line:

nix.registry.nixpkgs.flake = pkgs.callPackage myLib.mkUnfreeNixpkgs { path = inputs.nixpkgs; };

Here's a comparison.

The line commented out

Screencast.from.2024-10-18.00-48-54.webm

The line included

Screencast.from.2024-10-18.00-45-34.webm

I'm unsure as to why this might be. I thought it was some caching thing that I could replicate with cachix, but no, it works without internet. I'm guessing that somehow the default nixpkgs derivation gets special treatment and is always accessible, while our derivation isn't treated as nicely.

@Frontear, if you have any ideas as to why this is, let me know!

[Frontear]

I suspect this is due to the lack of a lock file. Something like lazy trees would fix this, but that's not here yet.

[llakala]

I suspect this is due to the lack of a lock file. Something like lazy trees would fix this, but that's not here yet.

It's always lazy trees...

[llakala]

For now, this works as a workaround. Only the unfree registries have the ~3-second delay, so I can only use those when actually needed.

nix.registry = lib.mkForce 
{
  nixpkgs.flake = inputs.nixpkgs;
  nixpkgs-unstable.flake = inputs.nixpkgs-unstable;

  # Allow running unfree packages with nix3 commands via `nix run unfree#steam`
  unfree.flake = pkgs.callPackage myLib.mkUnfreeNixpkgs { path = inputs.nixpkgs; };
  unfree-unstable.flake = pkgs.callPackage myLib.mkUnfreeNixpkgs { path = inputs.nixpkgs-unstable; };
};