Skip platform-irrelevant dotfiles packages during stow

iterm2 was being stowed on Linux and herbstluftwm/xorg on Darwin.
Add a built-in Darwin/Linux exclude default plus an excludePackages
override option in modules/home/dotfiles.nix, superseding the earlier
"accept harmless unused symlinks" decision.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01BBSd4VBfoKHjE1HR3P8kmn

1 files changed, 27 insertions, 0 deletions

diff --git a/modules/home/dotfiles.nix b/modules/home/dotfiles.nix
index 3df944c..21afb5e 100644
--- a/modules/home/dotfiles.nix
+++ b/modules/home/dotfiles.nix
@@ -2,6 +2,15 @@
 let
   cfg = config.home.dotfiles;
   dotfilesDir = "${config.home.homeDirectory}/dotfiles";
+
+  # Packages in the external dotfiles repo that are only relevant on one
+  # platform. Kept minimal and overridable via excludePackages rather than
+  # a full per-platform mapping - see design.md for alternatives considered.
+  platformDefaultExcludes =
+    lib.optionals (!pkgs.stdenv.isDarwin) [ "iterm2" ]
+    ++ lib.optionals (!pkgs.stdenv.isLinux) [ "herbstluftwm" "xorg" ];
+
+  excludePackages = platformDefaultExcludes ++ cfg.excludePackages;
 in
 {
   options.home.dotfiles.repoUrl = lib.mkOption {
@@ -10,11 +19,18 @@ in
     description = "Git URL of the personal dotfiles repo to clone and stow into $HOME. Leave empty to disable.";
   };
 
+  options.home.dotfiles.excludePackages = lib.mkOption {
+    type = lib.types.listOf lib.types.str;
+    default = [ ];
+    description = "Names of dotfiles stow packages to always skip, in addition to built-in platform defaults.";
+  };
+
   config = lib.mkIf (cfg.repoUrl != "") {
     home.packages = [ pkgs.git pkgs.stow ];
 
     home.activation.dotfiles = lib.hm.dag.entryAfter [ "writeBoundary" ] ''
       DOTFILES_DIR=${lib.escapeShellArg dotfilesDir}
+      EXCLUDE_PACKAGES=(${lib.escapeShellArgs excludePackages})
       if [ ! -d "$DOTFILES_DIR/.git" ]; then
         $DRY_RUN_CMD ${pkgs.git}/bin/git clone --recurse-submodules \
           ${lib.escapeShellArg cfg.repoUrl} "$DOTFILES_DIR"
@@ -23,6 +39,17 @@ in
         for pkg in "$DOTFILES_DIR"/*/; do
           pkg_name="$(basename "$pkg")"
           case "$pkg_name" in .*) continue ;; esac
+          skip=false
+          for excluded in "''${EXCLUDE_PACKAGES[@]}"; do
+            if [ "$pkg_name" = "$excluded" ]; then
+              skip=true
+              break
+            fi
+          done
+          if [ "$skip" = true ]; then
+            echo "Skipping dotfiles package '$pkg_name' — not relevant on this platform." >&2
+            continue
+          fi
           $DRY_RUN_CMD ${pkgs.stow}/bin/stow -d "$DOTFILES_DIR" -t ${lib.escapeShellArg config.home.homeDirectory} "$pkg_name" \
             || echo "Warning: stow failed for package '$pkg_name' — skipped." >&2
         done