Closes NixOS#194056 Alternative implementation to NixOS#80582 `nixpkgs.config` is now a freeform-type which imports the `<nixpkgs/pkgs/top-level/config.nix>`-module. This brings the following benefits: * Proper merging (to a certain degree, more details later) of several `nixpkgs.config` declarations. * `allowUnfree` and friends appear in the NixOS manual. To be precise, this means that something like this is now possible: { nixpkgs = mkMerge [ { allowUnfree = false; } { allowUnfree = mkForce true; } ]; } Previously this would lead to a bogus attr-set, namely { _type = "override"; content = true; priority = 50; } since no merging for this option-type was implemented. This however has certain limitations. For instance nixpkgs.config.allowUnfree = mkForce false; works fine whereas nixpkgs.config.virtualbox.enableExtensionPack = mkForce true; doesn't. This is because we use `types.raw` inside the config-module for `nixpkgs` which doesn't merge undeclared attribute-sets (such as `virtualbox`). This is because we don't know if any attribute-set is actually mergeable, for further details see the previous discussion[1]. A basic type has been implemented for the (actually deprecated) mechanisms `packageOverrides`/`perlPackageOverrides`. This one basically applies the `pkgs` argument onto each definition of this function, so e.g. the following expression { nixpkgs.config = mkMerge [ { packageOverrides = pkgs: { randomattr = 23; }; } { packageOverrides = pkgs: { randomattr = pkgs.randomattr + 19; }; } ]; } adds an attribute `randomattr` of value `42` to `_module.args.pkgs`. [1] NixOS#194207 (comment)

Commits

Commits on Oct 13, 2022

nixos/nixpkgs: make nixpkgs.config mergeable

nixos/nixpkgs: make `nixpkgs.config` mergeable