feat(darwinProfiles): add nix

nixos/darwinProfiles/presets/nix/default.nix

@@ -0,0 +1,39 @@
+{
+  lib,
+  pkgs,
+  loadSubmodule,
+}:
+let
+  l = lib // builtins;
+  inherit (pkgs.stdenv.hostPlatform) isAarch64;
+in
+{
+  imports = [ (loadSubmodule ./optimise.nix) ];
+  nix = {
+    package = pkgs.nixUnstable;
+    configureBuildUsers = true;
+    settings = {
+      # Administrative users on Darwin systems are part of the admin group.
+      trusted-users = [ "@admin" ];
+      extra-platforms = l.mkIf isAarch64 [
+        "x86_64-darwin"
+        "aarch64-darwin"
+      ];
+      auto-optimise-store = false;
+      experimental-features = [
+        "nix-command"
+        "flakes"
+        "recursive-nix"
+      ];
+      sandbox = false;
+      # https://github.com/NixOS/nix/issues/7273
+    };
+    extraOptions = ''
+      # https://plutus-community.readthedocs.io/en/latest/#Environment/Build/Mac_M1/
+      extra-sandbox-paths = /System/Library/Frameworks /System/Library/PrivateFrameworks /usr/lib /private/tmp /private/var/tmp /usr/bin/env
+    '';
+  };
+  services.nix-daemon.enable = true;
+  # Recreate /run/current-system symlink after boot
+  # services.activate-system.enable = true;
+}

nixos/darwinProfiles/presets/nix/optimise.nix

@@ -0,0 +1,33 @@
+# credit: https://github.com/montchr/dotfield/blob/68f6c9c3f6cc67c5c775b8a2a3f93cae6a76b3a5/profiles/darwinProfiles/core/nix-optimizations-darwin.nix#L9
+{ config }:
+{
+  nix.settings.auto-optimise-store = false;
+  # While it’s possible to set `auto-optimise-store` in `nix.conf`, it sometimes causes problems
+  # on Darwin.  Run a job periodically to optimise the store.
+  launchd.daemons."nix-store-optimise".serviceConfig = {
+    ProgramArguments = [
+      "/bin/sh"
+      "-c"
+      ''
+        /bin/wait4path ${config.nix.package}/bin/nix && \
+          exec ${config.nix.package}/bin/nix store optimise
+      ''
+    ];
+    StartCalendarInterval = [ {
+      Hour = 2;
+      Minute = 0;
+    } ];
+    StandardErrorPath = "/var/log/nix-store.log";
+    StandardOutPath = "/var/log/nix-store.log";
+  };
+
+  nix.gc = {
+    automatic = true;
+    interval = {
+      Weekday = 0;
+      Hour = 2;
+      Minute = 0;
+    };
+    options = "--delete-older-than 30d";
+  };
+}

tests/_snapshots/darwin

@@ -32,4 +32,8 @@
       name = "font-fontawesome";
     }
   ];
+  darwinNixProfile = ''
+    # https://plutus-community.readthedocs.io/en/latest/#Environment/Build/Mac_M1/
+    extra-sandbox-paths = /System/Library/Frameworks /System/Library/PrivateFrameworks /usr/lib /private/tmp /private/var/tmp /usr/bin/env
+  '';
 }

tests/darwin/expr.nix

@@ -12,7 +12,13 @@ in
   darwinFontProfile =
     (exporter.layouts.darwinConfiguration [
       omnibus.darwinProfiles.presets.homebrew
+      omnibus.darwinProfiles.presets.nix
       { homebrew.__profiles__.fonts = true; }
     ]).config.homebrew.casks;
+
+  darwinNixProfile =
+    (exporter.layouts.darwinConfiguration [ omnibus.darwinProfiles.presets.nix ])
+    .config.nix.extraOptions;
 }
+
 // lib.optionalAttrs trace { }