{environment,readme}: default configuration path to /etc/nix-darwin

CHANGELOG

@@ -1,3 +1,11 @@
+2025-01-18
+- The default configuration path for all new installations
+  is `/etc/nix-darwin`. This was already the undocumented
+  default for `darwin-rebuild switch` when using flakes. This
+  is implemented by setting `environment.darwinConfig` to
+  `"/etc/nix-darwin/configuration.nix"` by default when
+  `system.stateVersion` ≥ 6.
+
 2024-09-10
 - The default Nix build user group ID is now set to 350 when
   `system.stateVersion` ≥ 5, to reflect the default for new Nix

README.md

@@ -33,11 +33,12 @@ Despite being an experimental feature in Nix currently, nix-darwin recommends th
 <summary>Getting started from scratch</summary>
 <p></p>
 
-If you don't have an existing `configuration.nix`, you can run the following commands to generate a basic `flake.nix` inside `~/.config/nix-darwin`:
+If you don't have an existing `configuration.nix`, you can run the following commands to generate a basic `flake.nix` inside `/etc/nix-darwin`:
 
 ```bash
-mkdir -p ~/.config/nix-darwin
-cd ~/.config/nix-darwin
+sudo mkdir -p /etc/nix-darwin
+sudo chown $(id -nu):$(id -ng) /etc/nix-darwin
+cd /etc/nix-darwin
 
 # To use Nixpkgs unstable:
 nix flake init -t nix-darwin/master
@@ -88,15 +89,15 @@ Make sure to set `nixpkgs.hostPlatform` in your `configuration.nix` to either `x
 Unlike NixOS, `nix-darwin` does not have an installer, you can just run `darwin-rebuild switch` to install nix-darwin. As `darwin-rebuild` won't be installed in your `PATH` yet, you can use the following command:
 
 ```bash
-nix run nix-darwin -- switch --flake ~/.config/nix-darwin
+nix run nix-darwin -- switch
 ```
 
 ### Step 3. Using `nix-darwin`
 
 After installing, you can run `darwin-rebuild` to apply changes to your system:
 
 ```bash
-darwin-rebuild switch --flake ~/.config/nix-darwin
+darwin-rebuild switch
 ```
 
 #### Using flake inputs
@@ -124,7 +125,7 @@ nix-darwin.lib.darwinSystem {
 
 ### Step 1. Creating `configuration.nix`
 
-Copy the [simple](./modules/examples/simple.nix) example to `~/.config/nix-darwin/configuration.nix`.
+Copy the [simple](./modules/examples/simple.nix) example to `/etc/nix-darwin/configuration.nix`.
 
 ### Step 2. Adding `nix-darwin` channel
 
@@ -143,7 +144,7 @@ To install `nix-darwin`, you can just run `darwin-rebuild switch` to install nix
 
 ```bash
 nix-build '<darwin>' -A darwin-rebuild
-./result/bin/darwin-rebuild switch -I darwin-config=$HOME/.config/nix-darwin/configuration.nix
+./result/bin/darwin-rebuild switch
 ```
 
 ### Step 4. Using `nix-darwin`

modules/environment/default.nix

@@ -67,8 +67,24 @@ in
     };
 
     environment.darwinConfig = mkOption {
-      type = types.either types.path types.str;
-      default = "$HOME/.nixpkgs/darwin-configuration.nix";
+      type = types.nullOr (types.either types.path types.str);
+      default =
+        if config.nixpkgs.flake.setNixPath then
+          # Don’t set this for flake‐based systems.
+          null
+        else if config.system.stateVersion >= 6 then
+          "/etc/nix-darwin/configuration.nix"
+        else
+          "$HOME/.nixpkgs/darwin-configuration.nix";
+      defaultText = literalExpression ''
+        if config.nixpkgs.flake.setNixPath then
+          # Don’t set this for flake‐based systems.
+          null
+        else if config.system.stateVersion >= 6 then
+          "/etc/nix-darwin/configuration.nix"
+        else
+          "$HOME/.nixpkgs/darwin-configuration.nix"
+      '';
       description = ''
         The path of the darwin configuration.nix used to configure the system,
         this updates the default darwin-config entry in NIX_PATH. Since this

modules/examples/flake/flake.nix

@@ -27,7 +27,7 @@
 
       # Used for backwards compatibility, please read the changelog before changing.
       # $ darwin-rebuild changelog
-      system.stateVersion = 5;
+      system.stateVersion = 6;
 
       # The platform the configuration will be used on.
       nixpkgs.hostPlatform = "aarch64-darwin";

modules/examples/hydra.nix

@@ -43,5 +43,5 @@ in
     echo "ok"
   '';
 
-  system.stateVersion = 5;
+  system.stateVersion = 6;
 }

modules/examples/lnl.nix

@@ -199,7 +199,7 @@
   programs.zsh.enableFzfGit = true;
   programs.zsh.enableFzfHistory = true;
 
-  programs.zsh.variables.cfg = "$HOME/.config/nixpkgs/darwin/configuration.nix";
+  programs.zsh.variables.cfg = "/etc/nix-darwin/configuration.nix";
   programs.zsh.variables.darwin = "$HOME/.nix-defexpr/darwin";
   programs.zsh.variables.nixpkgs = "$HOME/.nix-defexpr/nixpkgs";
 
@@ -322,5 +322,5 @@
   nix.configureBuildUsers = true;
   nix.nrBuildUsers = 32;
 
-  system.stateVersion = 5;
+  system.stateVersion = 6;
 }

modules/examples/simple.nix

@@ -7,13 +7,10 @@
     [ pkgs.vim
     ];
 
-  # Use custom location for configuration.nix.
-  environment.darwinConfig = "$HOME/.config/nix-darwin/configuration.nix";
-
   # Enable alternative shell support in nix-darwin.
   # programs.fish.enable = true;
 
   # Used for backwards compatibility, please read the changelog before changing.
   # $ darwin-rebuild changelog
-  system.stateVersion = 5;
+  system.stateVersion = 6;
 }

modules/system/checks.nix

@@ -196,7 +196,7 @@ let
     darwinConfig=$(NIX_PATH=$nixPath nix-instantiate --find-file darwin-config) || true
     if ! test -e "$darwinConfig"; then
         echo "error: Changed <darwin-config> but target does not exist, aborting activation" >&2
-        echo "Create ''${darwinConfig:-~/.nixpkgs/darwin-configuration.nix} or set environment.darwinConfig:" >&2
+        echo "Create ''${darwinConfig:-/etc/nix-darwin/configuration.nix} or set environment.darwinConfig:" >&2
         echo >&2
         echo "    environment.darwinConfig = \"$(nix-instantiate --find-file darwin-config 2> /dev/null || echo '***')\";" >&2
         echo >&2

modules/system/version.nix

@@ -51,7 +51,7 @@ in
     system.maxStateVersion = mkOption {
       internal = true;
       type = types.int;
-      default = 5;
+      default = 6;
     };
 
     system.darwinLabel = mkOption {