refactor(flake): move custom packages to overlay

configs/nixos/modules/desktop/session/waybar.nix

@@ -21,7 +21,15 @@ let
   modules = lib.attrByPath [ config.networking.hostName ] { } config.registry.waybar;
 in
 {
-  options.modules.desktop.session.waybar.enable = lib.mkEnableOption "the Waybar status bar";
+  options.modules.desktop.session.waybar = {
+    enable = lib.mkEnableOption "the Waybar status bar";
+
+    package = lib.mkOption {
+      type = lib.types.package;
+      default = pkgs.alexion.waybar;
+      description = "Waybar package used by the status bar.";
+    };
+  };
 
   config = lib.mkIf config.modules.desktop.session.waybar.enable {
     # A symbols font backs the module glyphs, so pango falls back to it for the
@@ -30,32 +38,7 @@ in
 
     home-manager.users.${config.user.name}.programs.waybar = {
       enable = true;
-      # Waybar 0.15.0 sends old Hyprland workspace dispatch commands.
+      package = config.modules.desktop.session.waybar.package;
-      # Use the fix commit until a release includes upstream PR #5013.
-      package = pkgs.waybar.overrideAttrs {
-        src = pkgs.fetchFromGitHub {
-          owner = "Alexays";
-          repo = "Waybar";
-          rev = "05945748dccce28bf96d26d8f64a9e69a8dd49ba";
-          hash = "sha256-51R3mIt8cLNvh/X5qe9vOqeJCj0U9KRyemVE5y+OhiU=";
-        };
-
-        postUnpack =
-          let
-            libcava = pkgs.fetchFromGitHub {
-              owner = "LukashonakV";
-              repo = "cava";
-              tag = "0.10.7";
-              hash = "sha256-zkyj1vBzHtoypX4Bxdh1Vmwh967DKKxN751v79hzmgQ=";
-            };
-          in
-          ''
-            pushd "$sourceRoot"
-            cp -R --no-preserve=mode,ownership ${libcava} subprojects/cava-0.10.7
-            patchShebangs .
-            popd
-          '';
-      };
 
       # A user service bound to graphical-session.target, which uwsm activates,
       # so the bar comes up with the session and no compositor exec-once.

configs/nixos/modules/shell/pi/default.nix

@@ -14,16 +14,19 @@ in
 {
   options.modules.shell.pi = {
     enable = lib.mkEnableOption "Pi, a terminal coding agent, configured through home-manager";
+
+    package = lib.mkOption {
+      type = lib.types.package;
+      default = pkgs.alexion.pi-coding-agent;
+      description = "Pi package installed for the primary user.";
+    };
   };
 
   config = lib.mkIf config.modules.shell.pi.enable {
     home-manager.users.${user} = {
       programs.pi-coding-agent = {
         enable = true;
-        package = pkgs.pi-coding-agent.overrideAttrs {
+        package = config.modules.shell.pi.package;
-          src = ../../../../../third_party/pi;
-          patches = [ ];
-        };
 
         settings = {
           defaultProvider = "openai-codex";

src/dotfiles/hosts.nix

@@ -24,6 +24,10 @@ let
         inputs.sops-nix.nixosModules.sops
         inputs.stylix.nixosModules.stylix
 
+        {
+          nixpkgs.overlays = [ specialArgs.self.overlays.default ];
+        }
+
         repositoryModules
         guestModules
 

src/flake/default.nix

@@ -5,7 +5,18 @@
   root,
   system,
 }:
+let
+  overlay = import ./overlay.nix { inherit root; };
+  pkgs = import inputs.nixpkgs {
+    inherit system;
+    overlays = [ overlay ];
+  };
+in
 {
+  overlays.default = overlay;
+
+  packages.${system} = pkgs.alexion;
+
   nixosConfigurations = import ../dotfiles {
     inherit
       inputs

src/flake/overlay.nix

@@ -0,0 +1,7 @@
+{ root }:
+final: _prev: {
+  alexion = import ./packages {
+    pkgs = final;
+    inherit root;
+  };
+}

src/flake/packages/default.nix

@@ -0,0 +1,8 @@
+{ pkgs, root }:
+{
+  pi-coding-agent = pkgs.callPackage ./pi-coding-agent.nix {
+    inherit root;
+  };
+
+  waybar = pkgs.callPackage ./waybar.nix { };
+}

src/flake/packages/pi-coding-agent.nix

@@ -0,0 +1,8 @@
+{
+  pi-coding-agent,
+  root,
+}:
+pi-coding-agent.overrideAttrs {
+  src = root + "/third_party/pi";
+  patches = [ ];
+}

src/flake/packages/waybar.nix

@@ -0,0 +1,28 @@
+{
+  fetchFromGitHub,
+  waybar,
+}:
+waybar.overrideAttrs {
+  src = fetchFromGitHub {
+    owner = "Alexays";
+    repo = "Waybar";
+    rev = "05945748dccce28bf96d26d8f64a9e69a8dd49ba";
+    hash = "sha256-51R3mIt8cLNvh/X5qe9vOqeJCj0U9KRyemVE5y+OhiU=";
+  };
+
+  postUnpack =
+    let
+      libcava = fetchFromGitHub {
+        owner = "LukashonakV";
+        repo = "cava";
+        tag = "0.10.7";
+        hash = "sha256-zkyj1vBzHtoypX4Bxdh1Vmwh967DKKxN751v79hzmgQ=";
+      };
+    in
+    ''
+      pushd "$sourceRoot"
+      cp -R --no-preserve=mode,ownership ${libcava} subprojects/cava-0.10.7
+      patchShebangs .
+      popd
+    '';
+}