nixpkgs: switch to read-only packages

Signed-off-by: Bloxx12 <charlie@charlieroot.dev>
Change-Id: I6a6a69641b8369b151024324d8d06f2acb790c15

default.nix

@@ -1,5 +1,5 @@
 let
-  inherit (builtins) currentSystem filter mapAttrs;
+  inherit (builtins) filter mapAttrs;
 
   # https://github.com/andir/npins?tab=readme-ov-file#using-the-nixpkgs-fetchers
   src = import ./npins;
@@ -20,10 +20,7 @@ let
       modules = [
         # This is used to pre-emptively set the hostPlatform for nixpkgs.
         # Also, we set the system hostname here.
-        {
+        { networking.hostName = hostname; }
-          networking.hostName = hostname;
-          nixpkgs.hostPlatform = system;
-        }
         ./hosts/common.nix
         ./hosts/${hostname}
       ]

modules/system/nix/nixpkgs.mod.nix

@@ -1,47 +1,62 @@
-# taken from raf
-{ sources, ... }:
 {
-  # Global nixpkgs configuration.
+  lib,
-  # This is ignored if nixpkgs.pkgs is set, which should be avoided.
+  sources,
-  nixpkgs = {
+  pkgs,
-    flake = {
+  ...
-      source = sources.nixpkgs;
+}:
-      setFlakeRegistry = true;
+let
-      setNixPath = true;
+  inherit (lib.options) mkOption;
-    };
+  inherit (lib.types) str;
+in
+{
+  imports = [
+    # Going full schizo
+    "${sources.nixpkgs}/nixos/modules/misc/nixpkgs/read-only.nix"
+  ];
 
-    # Configuration reference:
+  options.nixpkgs.system = mkOption {
-    # <https://nixos.org/manual/nixpkgs/unstable/#chap-packageconfig>
+    type = str;
-    config = {
+    default = pkgs.system;
-      # Disallow broken packages to be built.
+    readOnly = true;
-      allowBroken = false;
-
-      allowUnsupportedSystem = true;
-
-      # Warn when config contains an unrecognized attribute.
-      # This might be useful for getting a better configuration.
-      warnUndeclaredOptions = true;
-
-      # Allow unfree packages
-      allowUnfree = true;
-
-      # Permitted insecure packages in a system.
-      # Default to none, add more as necessary.
-      # Matrix also likes using deprecated libraries, which tend to go into this list.
-      # permittedInsecurePackages = [];
-
-      # Whether to set enableParallelBuilding to true by default while
-      # building nixpkgs packages. Changing the default causes a mass rebuild.
-      enableParallelBuildingByDefault = false;
-
-      # Whether to expose old attribute names for compatibility.
-      # This improves backwards compatibility,
-      # which I could not care less about in my configuration.
-      allowAliases = false;
-
-      # List of derivation warnings to display while rebuilding.
-      #  See: <https://github.com/NixOS/nixpkgs/blob/master/pkgs/stdenv/generic/check-meta.nix>
-      showDerivationWarnings = [ ];
-    };
   };
+
+  config.nixpkgs.pkgs = (
+    import sources.nixpkgs {
+      hostPlatform = pkgs.stdenv.hostPlatform;
+      overlays = [ ];
+      config = {
+        # Configuration reference:
+        # <https://nixos.org/manual/nixpkgs/unstable/#chap-packageconfig>
+        # Disallow broken packages to be built.
+        allowBroken = false;
+
+        allowUnsupportedSystem = true;
+
+        # Warn when config contains an unrecognized attribute.
+        # This might be useful for getting a better configuration.
+        warnUndeclaredOptions = true;
+
+        # Allow unfree packages
+        allowUnfree = true;
+
+        # Permitted insecure packages in a system.
+        # Default to none, add more as necessary.
+        # Matrix also likes using deprecated libraries, which tend to go into this list.
+        # permittedInsecurePackages = [];
+
+        # Whether to set enableParallelBuilding to true by default while
+        # building nixpkgs packages. Changing the default causes a mass rebuild.
+        enableParallelBuildingByDefault = false;
+
+        # Whether to expose old attribute names for compatibility.
+        # This improves backwards compatibility,
+        # which I could not care less about in my configuration.
+        allowAliases = false;
+
+        # List of derivation warnings to display while rebuilding.
+        #  See: <https://github.com/NixOS/nixpkgs/blob/master/pkgs/stdenv/generic/check-meta.nix>
+        showDerivationWarnings = [ ];
+      };
+    }
+  );
 }