nixos/sway: Extend the default configuration for NixOS

The default config.in template contains
"include @sysconfdir@/sway/config.d/*" but we've dropped it to better
support non-NixOS (which seems like a mistake in retrospect).
This restores that behaviour and extends the default configuration via
nixos.conf to fix #119445.

Note: The security configurations (security.d) where dropped entirely
(but maybe they'll return).

nixos/modules/programs/sway.nix

@@ -31,6 +31,7 @@ let
     extraOptions = cfg.extraOptions;
     withBaseWrapper = cfg.wrapperFeatures.base;
     withGtkWrapper = cfg.wrapperFeatures.gtk;
+    isNixOS = true;
   };
 in {
   options.programs.sway = {
@@ -120,8 +121,11 @@ in {
       systemPackages = [ swayPackage ] ++ cfg.extraPackages;
       etc = {
         "sway/config".source = mkOptionDefault "${swayPackage}/etc/sway/config";
-        #"sway/security.d".source = mkOptionDefault "${swayPackage}/etc/sway/security.d/";
+        "sway/config.d/nixos.conf".source = pkgs.writeText "nixos.conf" ''
-        #"sway/config.d".source = mkOptionDefault "${swayPackage}/etc/sway/config.d/";
+          # Import the most important environment variables into the D-Bus and systemd
+          # user environments (e.g. required for screen sharing and Pinentry prompts):
+          exec dbus-update-activation-environment --systemd DISPLAY WAYLAND_DISPLAY SWAYSOCK
+        '';
       };
     };
     security.pam.services.swaylock = {};

pkgs/applications/window-managers/sway/default.nix

@@ -4,6 +4,8 @@
 , pango, cairo, libinput, libcap, pam, gdk-pixbuf, librsvg
 , wlroots, wayland-protocols, libdrm
 , nixosTests
+# Used by the NixOS module:
+, isNixOS ? false
 }:
 
 stdenv.mkDerivation rec {
@@ -27,6 +29,10 @@ stdenv.mkDerivation rec {
     })
   ];
 
+  postPatch = lib.optionalString isNixOS ''
+    echo -e '\ninclude /etc/sway/config.d/*' >> config.in
+  '';
+
   nativeBuildInputs = [
     meson ninja pkg-config wayland scdoc
   ];

pkgs/applications/window-managers/sway/wrapper.nix

@@ -4,6 +4,8 @@
 , withBaseWrapper ? true, extraSessionCommands ? "", dbus
 , withGtkWrapper ? false, wrapGAppsHook, gdk-pixbuf, glib, gtk3
 , extraOptions ? [] # E.g.: [ "--verbose" ]
+# Used by the NixOS module:
+, isNixOS ? false
 }:
 
 assert extraSessionCommands != "" -> withBaseWrapper;
@@ -11,6 +13,7 @@ assert extraSessionCommands != "" -> withBaseWrapper;
 with lib;
 
 let
+  sway = sway-unwrapped.override { inherit isNixOS; };
   baseWrapper = writeShellScriptBin "sway" ''
      set -o errexit
      if [ ! "$_SWAY_WRAPPER_ALREADY_EXECUTED" ]; then
@@ -19,16 +22,16 @@ let
      fi
      if [ "$DBUS_SESSION_BUS_ADDRESS" ]; then
        export DBUS_SESSION_BUS_ADDRESS
-       exec ${sway-unwrapped}/bin/sway "$@"
+       exec ${sway}/bin/sway "$@"
      else
-       exec ${dbus}/bin/dbus-run-session ${sway-unwrapped}/bin/sway "$@"
+       exec ${dbus}/bin/dbus-run-session ${sway}/bin/sway "$@"
      fi
    '';
 in symlinkJoin {
-  name = "sway-${sway-unwrapped.version}";
+  name = "sway-${sway.version}";
 
   paths = (optional withBaseWrapper baseWrapper)
-    ++ [ sway-unwrapped ];
+    ++ [ sway ];
 
   nativeBuildInputs = [ makeWrapper ]
     ++ (optional withGtkWrapper wrapGAppsHook);
@@ -48,5 +51,5 @@ in symlinkJoin {
 
   passthru.providedSessions = [ "sway" ];
 
-  inherit (sway-unwrapped) meta;
+  inherit (sway) meta;
 }