Slight refactor

.github/workflows/nix-test.yaml

@@ -20,7 +20,7 @@ jobs:
       contents: read
       id-token: write
     env:
-      CI_HOSTNAME: ci-${{ matrix.os.name }}
+      CI_FLAKE_TARGET: ci
     runs-on: ${{ matrix.os.name }}
     strategy:
       fail-fast: false
@@ -47,7 +47,6 @@ jobs:
           use-gha-cache: enabled
       - name: Setup
         run: |
-          sed -i '' "s/defaultHostname/${CI_HOSTNAME}/g" flake.nix
           sed -i '' "s/defaultSystem/${{matrix.os.arch}}/g" flake.nix
           sed -i '' "s/defaultVersion/$(sw_vers --productVersion | cut -d. -f1)/g" flake.nix
 
@@ -71,15 +70,15 @@ jobs:
         env:
           NIX_CONFIG: "access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}"
         run: |
-          sudo -E nix run nix-darwin/master#darwin-rebuild --extra-experimental-features "nix-command flakes" -- switch --flake .#${CI_HOSTNAME}
+          sudo -E nix run nix-darwin/master#darwin-rebuild --extra-experimental-features "nix-command flakes" -- switch --flake .#${CI_FLAKE_TARGET}
 
       - name: Test - Switch
         # See https://github.com/actions/runner-images/issues/264
         shell: zsh {0}
         env:
           NIX_CONFIG: "access-tokens = github.com=${{ secrets.GITHUB_TOKEN }}"
         run: |
-          sudo -E darwin-rebuild switch --flake .#${CI_HOSTNAME}
+          sudo -E darwin-rebuild switch --flake .#${CI_FLAKE_TARGET}
 
       # - name: Test - bashrc
       #   run: bash -c "source ~/.bashrc"

.gitignore

@@ -5,6 +5,7 @@ ssh/known_hosts
 ssh/google*
 ssh/*Github
 secrets
+darwin/local-flake-target
 rbenv/*/
 .DS_Store
 
@@ -13,4 +14,4 @@ gitconfig-user
 
 .direnv
 .pre-commit-config.yaml
-.prettierignore
+.prettierignore

README.md

@@ -19,19 +19,30 @@ Opinionated `nix-darwin` and Home Manager configuration for bringing a clean mac
    cd ~/.dotfiles
    ```
 
-3. Perform the first system activation with the same command CI runs:
+3. Perform the first system activation with the public flake target that matches your machine:
 
    ```bash
-   nix run nix-darwin/master#darwin-rebuild --extra-experimental-features "nix-command flakes" -- switch --flake .
+   nix run nix-darwin/master#darwin-rebuild --extra-experimental-features "nix-command flakes" -- switch --flake .#darwin-arm64
    ```
 
-4. For day-to-day updates after the initial activation:
+   Use `darwin-arm64` for Apple Silicon machines and `darwin-x86_64` for Intel machines.
+
+4. Optionally set a private default target on each machine so the `switch` shell helper can stay host-agnostic:
+
+   ```bash
+   cp darwin/local-flake-target.example darwin/local-flake-target
+   $EDITOR darwin/local-flake-target
+   ```
+
+5. For day-to-day updates after the initial activation:
 
    ```bash
-   darwin-rebuild switch --flake .
+   switch
    ```
 
-5. Drop into the development shell whenever you need project tooling (`nixfmt`, `prettier`, git hooks, etc.):
+   You can also continue to use `darwin-rebuild switch --flake .#darwin-arm64` explicitly.
+
+6. Drop into the development shell whenever you need project tooling (`nixfmt`, `prettier`, git hooks, etc.):
 
    ```bash
    nix develop
@@ -60,14 +71,16 @@ bootstrap.sh          # Convenience script for bootstrapping fresh machines
 
 ## Everyday Commands
 
-- `darwin-rebuild switch --flake .` — Apply configuration changes to the current machine.
+- `switch [target]` — Apply configuration changes using a private local default or an explicit public target.
+- `darwin-rebuild switch --flake .#darwin-arm64` — Apply the Apple Silicon configuration explicitly.
+- `darwin-rebuild switch --flake .#darwin-x86_64` — Apply the Intel configuration explicitly.
 - `nix develop` — Enter the dev shell with formatters and pre-commit hooks configured.
 - `pre-commit run --all-files` — Lint and format Nix and text assets to match CI.
 - `nix flake update` — Refresh inputs and rewrite `flake.lock` when bumping dependencies.
 
 ## Validation & Testing
 
-- Run `darwin-rebuild switch --flake .` (or the CI command from Quick Start) after edits to confirm the macOS build succeeds.
+- Run `switch` or `darwin-rebuild switch --flake .#<public-target>` after edits to confirm the macOS build succeeds.
 - Use `nix flake check` to evaluate Home Manager modules on both `aarch64-darwin` and `x86_64-darwin`.
 - Source the interactive shell with `zsh -vc "source ~/.zshrc"` to ensure the login environment stays clean.
 

darwin/homebrew.nix

@@ -2,7 +2,6 @@
   inputs,
   lib,
   user,
-  hostname,
   osVersion,
   platform,
   ...
@@ -24,7 +23,9 @@ in
   homebrew = {
     enable = true;
     onActivation = {
-      autoUpdate = true;
+      # Avoid Homebrew self-updating on every rebuild while still allowing
+      # managed formula and cask upgrades during activation.
+      autoUpdate = false;
       upgrade = true;
     };
     brews = [
@@ -71,7 +72,6 @@ in
         "vagrant"
         "virtualbox"
         "visual-studio-code"
-        "zen"
       ];
 
     # Mac App Store apps

darwin/local-flake-target.example

@@ -0,0 +1,8 @@
+# Copy this file to darwin/local-flake-target on each machine and keep the
+# selected target private.
+#
+# Valid public targets:
+# - darwin-arm64
+# - darwin-x86_64
+
+darwin-arm64

flake.nix

@@ -60,7 +60,6 @@
       mkDarwinSystem =
         {
           system,
-          hostname,
           osVersion,
           username,
         }:
@@ -109,7 +108,6 @@
           specialArgs = {
             inherit
               inputs
-              hostname
               osVersion
               platform
               system
@@ -131,7 +129,6 @@
                 extraSpecialArgs = {
                   inherit
                     inputs
-                    hostname
                     platform
                     ;
                   user = user;
@@ -146,31 +143,30 @@
             }
           ];
         };
-    in
-    {
-      darwinConfigurations = {
-        "MSPLAIN-M-CH4Y" = mkDarwinSystem {
+
+      publicDarwinConfigurations = {
+        darwin-arm64 = mkDarwinSystem {
           system = "aarch64-darwin";
-          hostname = "MSPLAIN-M-CH4Y";
           osVersion = "26";
           username = "msplain";
         };
 
-        "Mikes-MBP-16" = mkDarwinSystem {
+        darwin-x86_64 = mkDarwinSystem {
           system = "x86_64-darwin";
-          hostname = "Mikes-MBP-16";
           osVersion = "26";
           username = "mike";
         };
 
         # For CI and testing
-        "defaultHostname" = mkDarwinSystem {
+        ci = mkDarwinSystem {
           system = "defaultSystem";
-          hostname = "defaultHostname";
           osVersion = "defaultVersion";
           username = "runner";
         };
       };
+    in
+    {
+      darwinConfigurations = publicDarwinConfigurations;
 
       # Import devShells from devshell.nix
       inherit (import ./devshell.nix { inherit inputs; }) devShells;

home/default.nix

@@ -3,7 +3,6 @@
   user,
   system,
   config,
-  hostname,
   ...
 }:
 let

home/git.nix

@@ -1,7 +1,6 @@
 {
   inputs,
   pkgs,
-  hostname,
   ...
 }:
 {

home/shell.nix

@@ -72,7 +72,7 @@
       High-level
         help                    Show this list
         dot, dotfiles           cd $HOME/.dotfiles
-        switch                  darwin-rebuild switch --flake .
+        switch [target]         darwin-rebuild switch --flake .#<target>
         update_flake_from_pr    Approve + merge latest successful flake update PR and pull
         w                       windsurf .
         c                       cursor .
@@ -137,9 +137,34 @@
 
             eval "$(mise activate zsh)"
 
+            darwin_flake_target() {
+              local target="$1"
+              local repo_dir="''${2:-$HOME/.dotfiles}"
+              local target_file="$repo_dir/darwin/local-flake-target"
+
+              if [[ -n "$target" ]]; then
+                print -r -- "$target"
+                return 0
+              fi
+
+              if [[ -f "$target_file" ]]; then
+                target=$(grep -Ev '^[[:space:]]*(#|$)' "$target_file" | head -n 1)
+                if [[ -n "$target" ]]; then
+                  print -r -- "$target"
+                  return 0
+                fi
+              fi
+
+              echo "No default Darwin flake target configured." >&2
+              echo "Pass a target like 'switch darwin-arm64' or create $target_file." >&2
+              return 1
+            }
+
             # Switch to the current flake
             switch() {
-              sudo darwin-rebuild switch --flake .
+              local target
+              target=$(darwin_flake_target "$1") || return 1
+              sudo darwin-rebuild switch --flake ".#''${target}"
             }
 
             # Approve + merge latest successful flake update PR and pull locally.