Setting nixpkgs.config in a module doesn't seem to work anymore about flake-utils-plus

[gytis-ivaskevicius]

As of commit states... I Will fix the breaking stuff later, but I am quite happy with the new implementation/dataflow of it.

Feel free to try out github:/gytis-ivaskevicius/flake-utils-plus/staging

Edit:
Also, I went through your config - one note: system = "x86_64-linux"; in nixosProfiles is redundant since that's the default

[gytis-ivaskevicius]

When using flake-utils-plus cases like these can be specified in two areas:

1. For channel-specific configuration (i believe this is what you are looking for) https://github.com/gytis-ivaskevicius/flake-utils-plus/blob/master/examples/fully-featured-flake.nix#L46-L48
2. Or globally (applied to all channels) https://github.com/gytis-ivaskevicius/flake-utils-plus/blob/master/examples/fully-featured-flake.nix#L63-L66

[chvp]

Yes, I found that, but I build up a list of allowed packages in the nixos modules for my machines, which I don't have access to at that point.

[gytis-ivaskevicius]

Interesting use case, admittedly I don't really see much point in doing something like that but ill look into it regardless. I obviously have not tested it but fix should be as simple as this:
Replace this code block: https://github.com/gytis-ivaskevicius/flake-utils-plus/blob/master/systemFlake.nix#L75-L85
with:

 {config, ...}:  {
          networking.hostName = name;

          nixpkgs = {
            pkgs = selectedNixpkgs;
            config = selectedNixpkgs.config // config.nixpkgs.config;
          };

          system.configurationRevision = mkIf (self ? rev) self.rev;
          nix.package = mkDefault selectedNixpkgs.nixUnstable;
        }

(two lines changed, will test it out once I am available)

[chvp]

That doesn't seem to work. I think the problem is caused by the pkgs = selectedNixpkgs; line. The config applied in nixpkgs.config doesn't seem to apply to it, but only to the nixpkgs that is used for nixpkgs.lib.nixosSystem. When I remove the pkgs = selectedNixpkgs line (and manually add the overlays I use) it works as expected.

[gytis-ivaskevicius]

Pushed some changes, fixed channels switching, few other changes.
What's unfortunate is that it seems that I will not be able to implement nixpkgs.config.xyz with the addition of channel patching (User will be forced to pick one of these features), but we will see. I Will give it some more thought overnight

The next release is planned for the weekend.

[chvp]

Ah, that is unfortunate, the easy patching was one of my main reasons for starting to use this. Am I correct in thinking that this is the main blocker for the combination? Do you know what the underlying issue is?

[gytis-ivaskevicius]

Yes, @chvp, you are correct. More specifically because of this NixOS/nix#4669.

But here is a solution to your specific problem:
TL;DR: implement explicit unfree package definitions in different manner
How?
in your flake.nix:

{
inputs.nixpkgs.input = nixpkgs;
inputs.nixpkgs.overlayBuilder = channels: [
    (final: prev: { unfree = channels.unfree; })
];

inputs.unfree.input = nixpkgs;
inputs.unfree.config.allowUnfree = true;
}

(untested, should more or less work, might have a typo or two)

And instead of building some fancy array of allowed packages now, you can define unfree packages by simply typing pkgs.unfree.google-chrome

This achieves the same result while being much simpler, easier to implement, and resulting in fewer lines of code

[chvp]

Hmm, that is an interesting alternative for making the unfree packages explicit. I'll try that out tomorrow. Thanks for the issue on nix, I subscribed to it to keep updated.

[chvp]

It took a while before I was able to get to it, but your solution doesn't seem to work. It refuses to evaluate because of unfree packages.

[gytis-ivaskevicius]

I got a strong feeling that this is going to be one of the limitations of Nix (patching + dynamic configuration). Will need to look into it more :/