nixos/dwl: init module (#403978)

nixos/doc/manual/release-notes/rl-2511.section.md

@@ -24,6 +24,8 @@
 
 - [SuiteNumérique Docs](https://github.com/suitenumerique/docs), a collaborative note taking, wiki and documentation web platform and alternative to Notion or Outline. Available as [services.lasuite-docs](#opt-services.lasuite-docs.enable).
 
+[dwl](https://codeberg.org/dwl/dwl), a compact, hackable compositor for Wayland based on wlroots. Available as [programs.dwl](#opt-programs.dwl.enable).
+
 ## Backward Incompatibilities {#sec-release-25.11-incompatibilities}
 
 <!-- To avoid merge conflicts, consider adding your item at an arbitrary place in the list instead. -->

nixos/modules/module-list.nix

@@ -332,6 +332,7 @@
   ./programs/vivid.nix
   ./programs/wavemon.nix
   ./programs/wayland/cardboard.nix
+  ./programs/wayland/dwl.nix
   ./programs/wayland/gtklock.nix
   ./programs/wayland/hyprland.nix
   ./programs/wayland/hyprlock.nix

nixos/modules/programs/wayland/dwl.nix

@@ -0,0 +1,104 @@
+{
+  config,
+  lib,
+  pkgs,
+  ...
+}:
+let
+  cfg = config.programs.dwl;
+in
+{
+  options.programs.dwl = {
+    enable = lib.mkEnableOption ''
+      Dwl is a compact, hackable compositor for Wayland based on wlroots.
+      You can manually launch Dwl by executing "exec dwl" on a TTY.
+    '';
+
+    package = lib.mkPackageOption pkgs "dwl" {
+      example = ''
+        # Lets apply bar patch from:
+        # https://codeberg.org/dwl/dwl-patches/src/branch/main/patches/bar
+        (pkgs.dwl.override {
+          configH = ./dwl-config.h;
+        }).overrideAttrs (oldAttrs: {
+          buildInputs =
+            oldAttrs.buildInputs or []
+            ++ [
+              pkgs.libdrm
+              pkgs.fcft
+            ];
+          patches = oldAttrs.patches or [] ++ [
+            ./bar-0.7.patch
+          ];
+        });
+      '';
+    };
+
+    extraSessionCommands = lib.mkOption {
+      default = "";
+      type = lib.types.lines;
+      description = ''
+        Shell commands executed just before dwl is started.
+      '';
+    };
+  };
+
+  config = lib.mkIf cfg.enable {
+    environment.systemPackages = [ cfg.package ];
+
+    # Create systemd target for dwl session
+    systemd.user.targets.dwl-session = {
+      description = "dwl compositor session";
+      documentation = [ "man:systemd.special(7)" ];
+      bindsTo = [ "graphical-session.target" ];
+      wants = [ "graphical-session-pre.target" ];
+      after = [ "graphical-session-pre.target" ];
+    };
+
+    # Create wrapper script for dwl
+    environment.etc."xdg/dwl-session" = {
+      text = ''
+        #!${pkgs.runtimeShell}
+        # Import environment variables
+        ${cfg.extraSessionCommands}
+        # Setup systemd user environment
+        systemctl --user import-environment DISPLAY WAYLAND_DISPLAY
+        systemctl --user start dwl-session.target
+        # Start dwl
+        exec ${lib.getExe cfg.package}
+      '';
+      mode = "0755"; # Make it executable
+    };
+
+    # Create desktop entry for display managers
+    services.displayManager.sessionPackages =
+      let
+        dwlDesktopFile = pkgs.writeTextFile {
+          name = "dwl-desktop-entry";
+          destination = "/share/wayland-sessions/dwl.desktop";
+          text = ''
+            [Desktop Entry]
+            Name=dwl
+            Comment=Dynamic window manager for Wayland
+            Exec=/etc/xdg/dwl-session
+            Type=Application
+          '';
+        };
+
+        dwlSession = pkgs.symlinkJoin {
+          name = "dwl-session";
+          paths = [ dwlDesktopFile ];
+          passthru.providedSessions = [ "dwl" ];
+        };
+      in
+      [ dwlSession ];
+
+    # Configure XDG portal for dwl (minimal configuration)
+    xdg.portal.config.dwl.default = lib.mkDefault [
+      "wlr"
+      "gtk"
+    ];
+  };
+
+  meta.maintainers = with lib.maintainers; [ gurjaka ];
+}

nixos/tests/all-tests.nix

@@ -414,6 +414,7 @@ in
   drupal = runTest ./drupal.nix;
   drbd-driver = runTest ./drbd-driver.nix;
   dublin-traceroute = runTest ./dublin-traceroute.nix;
+  dwl = runTestOn [ "x86_64-linux" "aarch64-linux" ] ./dwl.nix;
   earlyoom = handleTestOn [ "x86_64-linux" ] ./earlyoom.nix { };
   early-mount-options = handleTest ./early-mount-options.nix { };
   ec2-config = (handleTestOn [ "x86_64-linux" ] ./ec2.nix { }).boot-ec2-config or { };

nixos/tests/dwl.nix

@@ -0,0 +1,43 @@
+{ lib, ... }:
+{
+  name = "dwl_test_vm";
+
+  meta = {
+    maintainers = with lib.maintainers; [ gurjaka ];
+  };
+
+  nodes.machine =
+    {
+      pkgs,
+      lib,
+      ...
+    }:
+    {
+      imports = [
+        ./common/user-account.nix
+        ./common/wayland-cage.nix
+      ];
+
+      environment.systemPackages = [ pkgs.foot ];
+
+      services.displayManager.defaultSession = lib.mkForce "dwl";
+
+      programs.dwl.enable = true;
+    };
+
+  testScript = ''
+    with subtest("ensure dwl starts"):
+      machine.wait_for_file("/run/user/1000/wayland-0")
+
+    with subtest("ensure foot is installed"):
+      machine.succeed("which foot")
+
+    with subtest("ensure we can open a new terminal"):
+      # sleep 3 is required to make sure dwl has started
+      # TODO: find better way to identify dwl session
+      machine.sleep(3)
+      machine.send_key("alt-shift-ret")
+      machine.sleep(3)
+      machine.screenshot("terminal")
+  '';
+}