feat: add COSMIC specialisation

desktop/cosmic.nix

@@ -0,0 +1,17 @@
+{ inputs, lib, ... }:
+
+{
+  imports = [ inputs.nixos-cosmic.nixosModules.default ];
+
+  # TODO at the moment COSMIC cannot be used alongside Gnome
+  # https://github.com/lilyinstarlight/nixos-cosmic/issues/17
+  specialisation = {
+    cosmic.configuration = {
+      services.xserver.displayManager.gdm.enable = lib.mkForce false;
+      services.xserver.desktopManager.gnome.enable = lib.mkForce false;
+
+      services.desktopManager.cosmic.enable = true;
+      services.displayManager.cosmic-greeter.enable = true;
+    };
+  };
+}

flake.lock

@@ -156,6 +156,22 @@
       }
     },
     "flake-compat_3": {
+      "flake": false,
+      "locked": {
+        "lastModified": 1688025799,
+        "narHash": "sha256-ktpB4dRtnksm9F5WawoIkEneh1nrEvuxb5lJFt1iOyw=",
+        "owner": "nix-community",
+        "repo": "flake-compat",
+        "rev": "8bf105319d44f6b9f0d764efa4fdef9f1cc9ba1c",
+        "type": "github"
+      },
+      "original": {
+        "owner": "nix-community",
+        "repo": "flake-compat",
+        "type": "github"
+      }
+    },
+    "flake-compat_4": {
       "flake": false,
       "locked": {
         "lastModified": 1696426674,
@@ -325,6 +341,27 @@
         "type": "github"
       }
     },
+    "nixos-cosmic": {
+      "inputs": {
+        "flake-compat": "flake-compat_3",
+        "nixpkgs": [
+          "nixpkgs"
+        ]
+      },
+      "locked": {
+        "lastModified": 1716687322,
+        "narHash": "sha256-1s8dbw0eSSd2ygsjPsWcxhuSgXiRgj88aNGclXbhBDQ=",
+        "owner": "lilyinstarlight",
+        "repo": "nixos-cosmic",
+        "rev": "13509b725c530f80a398573907cc29794183caa2",
+        "type": "github"
+      },
+      "original": {
+        "owner": "lilyinstarlight",
+        "repo": "nixos-cosmic",
+        "type": "github"
+      }
+    },
     "nixos-hardware": {
       "locked": {
         "lastModified": 1716715385,
@@ -410,7 +447,7 @@
     },
     "pre-commit-hooks": {
       "inputs": {
-        "flake-compat": "flake-compat_3",
+        "flake-compat": "flake-compat_4",
         "gitignore": "gitignore",
         "nixpkgs": [
           "nixpkgs"
@@ -443,6 +480,7 @@
         "flake-utils": "flake-utils_2",
         "home-manager": "home-manager_2",
         "matrix-appservices": "matrix-appservices",
+        "nixos-cosmic": "nixos-cosmic",
         "nixos-hardware": "nixos-hardware",
         "nixpkgs": "nixpkgs",
         "nixpkgs-unstable": "nixpkgs-unstable",

flake.nix

@@ -4,10 +4,12 @@ rec {
   nixConfig = {
     extra-substituters = [
       "https://nix-community.cachix.org"
+      "https://cosmic.cachix.org/"
       "https://felschr.cachix.org"
     ];
     extra-trusted-public-keys = [
       "nix-community.cachix.org-1:mB9FSh9qf2dCimDSUo8Zy7bkq5CX+/rkCWyvRCYg3Fs="
+      "cosmic.cachix.org-1:Dya9IyXD4xdBehWjrkPv6rtxpmMdRel02smYzA85dPE="
       "felschr.cachix.org-1:raomy5XA2tsVkBoG6wo70ARIn+V24IXhWaSe3QZo12A="
     ];
   };
@@ -69,6 +71,11 @@ rec {
       flake = false;
     };
 
+    nixos-cosmic = {
+      url = "github:lilyinstarlight/nixos-cosmic";
+      inputs.nixpkgs.follows = "nixpkgs";
+    };
+
     openwrt-imagebuilder = {
       url = "github:astro/nix-openwrt-imagebuilder";
       inputs.nixpkgs.follows = "nixpkgs";

hosts/home-pc.nix

@@ -11,6 +11,7 @@
     ../system/printing/home.nix
     ../system/gaming.nix
     ../desktop
+    ../desktop/cosmic.nix
     ../virtualisation/containers.nix
     ../virtualisation/podman.nix
     ../virtualisation/libvirt.nix