Add gnome wayland support

nixos/modules/services/x11/desktop-managers/gnome3.nix

@@ -136,19 +136,17 @@ in {
 
     services.xserver.displayManager.extraSessionFilePackages = [ pkgs.gnome3.gnome-session ];
 
-    services.xserver.displayManager.sessionCommands = ''
-      if test "$XDG_CURRENT_DESKTOP" = "GNOME"; then
-          ${concatMapStrings (p: ''
-            if [ -d "${p}/share/gsettings-schemas/${p.name}" ]; then
-              export XDG_DATA_DIRS=$XDG_DATA_DIRS''${XDG_DATA_DIRS:+:}${p}/share/gsettings-schemas/${p.name}
-            fi
-
-            if [ -d "${p}/lib/girepository-1.0" ]; then
-              export GI_TYPELIB_PATH=$GI_TYPELIB_PATH''${GI_TYPELIB_PATH:+:}${p}/lib/girepository-1.0
-              export LD_LIBRARY_PATH=$LD_LIBRARY_PATH''${LD_LIBRARY_PATH:+:}${p}/lib
-            fi
-          '') cfg.sessionPath}
-      fi
+    environment.extraInit = ''
+      ${concatMapStrings (p: ''
+        if [ -d "${p}/share/gsettings-schemas/${p.name}" ]; then
+          export XDG_DATA_DIRS=$XDG_DATA_DIRS''${XDG_DATA_DIRS:+:}${p}/share/gsettings-schemas/${p.name}
+        fi
+
+        if [ -d "${p}/lib/girepository-1.0" ]; then
+          export GI_TYPELIB_PATH=$GI_TYPELIB_PATH''${GI_TYPELIB_PATH:+:}${p}/lib/girepository-1.0
+          export LD_LIBRARY_PATH=$LD_LIBRARY_PATH''${LD_LIBRARY_PATH:+:}${p}/lib
+        fi
+      '') cfg.sessionPath}
     '';
 
     environment.variables.GNOME_SESSION_DEBUG = optionalString cfg.debug "1";

nixos/modules/services/x11/display-managers/default.nix

@@ -78,8 +78,7 @@ let
       # This is required by user units using the session bus.
       ${config.systemd.package}/bin/systemctl --user import-environment DISPLAY XAUTHORITY DBUS_SESSION_BUS_ADDRESS
 
-      # Load X defaults.
-      # FIXME: Check XDG_SESSION_TYPE against x11
+      # Load X defaults. This should probably be safe on wayland too.
       ${xorg.xrdb}/bin/xrdb -merge ${xresourcesXft}
       if test -e ~/.Xresources; then
           ${xorg.xrdb}/bin/xrdb -merge ~/.Xresources
@@ -194,6 +193,11 @@ let
       ${concatMapStrings (pkg: ''
         ${xorg.lndir}/bin/lndir ${pkg}/share/xsessions $out/share/xsessions
       '') cfg.displayManager.extraSessionFilePackages}
+
+      mkdir -p "$out/share/wayland-sessions"
+      ${concatMapStrings (pkg: ''
+        ${xorg.lndir}/bin/lndir ${pkg}/share/wayland-sessions $out/share/wayland-sessions
+      '') cfg.displayManager.extraSessionFilePackages}
     '';
 
 in
@@ -240,7 +244,10 @@ in
           ''
             xmessage "Hello World!" &
           '';
-        description = "Shell commands executed just before the window or desktop manager is started.";
+        description = ''
+          Shell commands executed just before the window or desktop manager is
+          started. These commands are not currently sourced for Wayland sessions.
+        '';
       };
 
       hiddenUsers = mkOption {

nixos/modules/services/x11/display-managers/sddm.nix

@@ -59,6 +59,7 @@ let
 
     [Wayland]
     EnableHidpi=${if cfg.enableHidpi then "true" else "false"}
+    SessionDir=${dmcfg.session.desktops}/share/wayland-sessions
 
     ${optionalString cfg.autoLogin.enable ''
     [Autologin]

nixos/tests/gnome3-gdm.nix

@@ -23,22 +23,38 @@ import ./make-test.nix ({ pkgs, ...} : {
       virtualisation.memorySize = 1024;
     };
 
-  testScript =
-    ''
-      # wait for gdm to start and bring up X
+  testScript = let
+    # Keep line widths somewhat managable
+    bus = "DBUS_SESSION_BUS_ADDRESS=unix:path=/run/user/1000/bus";
+    gdbus = "${bus} gdbus";
+    # Call javascript in gnome shell, returns a tuple (success, output), where
+    # `success` is true if the dbus call was successful and output is what the
+    # javascript evaluates to.
+    eval = "call --session -d org.gnome.Shell -o /org/gnome/Shell -m org.gnome.Shell.Eval";
+    # False when startup is done
+    startingUp = "${gdbus} ${eval} Main.layoutManager._startingUp";
+    # Hopefully gnome-terminal's wm class
+    wmClass = "${gdbus} ${eval} global.display.focus_window.wm_class";
+  in ''
+      # wait for gdm to start
       $machine->waitForUnit("display-manager.service");
-      $machine->waitForX;
 
       # wait for alice to be logged in
       $machine->waitForUnit("default.target","alice");
 
       # Check that logging in has given the user ownership of devices.
       $machine->succeed("getfacl /dev/snd/timer | grep -q alice");
 
-      # open a terminal and check it's there
-      $machine->succeed("su - alice -c 'DISPLAY=:0.0 XAUTHORITY=/run/user/\$UID/gdm/Xauthority gnome-terminal'");
-      $machine->succeed("xauth merge /run/user/1000/gdm/Xauthority");
-      $machine->waitForWindow(qr/Terminal/);
+      # Wait for the wayland server
+      $machine->waitForFile("/run/user/1000/wayland-0");
+
+      # Wait for gnome shell, correct output should be "(true, 'false')"
+      $machine->waitUntilSucceeds("su - alice -c '${startingUp} | grep -q true,..false'");
+
+      # open a terminal
+      $machine->succeed("su - alice -c '${bus} gnome-terminal'");
+      # and check it's there
+      $machine->waitUntilSucceeds("su - alice -c '${wmClass} | grep -q gnome-terminal-server'");
 
       # wait to get a nice screenshot
       $machine->sleep(20);

nixos/tests/gnome3.nix

@@ -16,7 +16,7 @@ import ./make-test.nix ({ pkgs, ...} : {
       services.xserver.displayManager.lightdm.autoLogin.enable = true;
       services.xserver.displayManager.lightdm.autoLogin.user = "alice";
       services.xserver.desktopManager.gnome3.enable = true;
-      services.xserver.desktopManager.default = "gnome";
+      services.xserver.desktopManager.default = "gnome-xorg";
 
       virtualisation.memorySize = 1024;
     };

pkgs/desktops/gnome-3/core/gnome-session/default.nix

@@ -1,6 +1,6 @@
 { fetchurl, stdenv, substituteAll, meson, ninja, pkgconfig, gnome3, glib, gtk, gsettings-desktop-schemas
 , gnome-desktop, dbus, json-glib, libICE, xmlto, docbook_xsl, docbook_xml_dtd_412, python3
-, libxslt, gettext, makeWrapper, systemd, xorg, epoxy }:
+, libxslt, gettext, makeWrapper, systemd, xorg, epoxy, gnugrep, bash }:
 
 stdenv.mkDerivation rec {
   name = "gnome-session-${version}";
@@ -16,6 +16,8 @@ stdenv.mkDerivation rec {
       src = ./fix-paths.patch;
       gsettings = "${glib.bin}/bin/gsettings";
       dbusLaunch = "${dbus.lib}/bin/dbus-launch";
+      grep = "${gnugrep}/bin/grep";
+      bash = "${bash}/bin/bash";
     })
   ];
 
@@ -37,8 +39,11 @@ stdenv.mkDerivation rec {
     patchShebangs meson_post_install.py
   '';
 
+  # `bin/gnome-session` will reset the environment when run in wayland, we
+  # therefor wrap `libexec/gnome-session-binary` instead which is the actual
+  # binary needing wrapping
   preFixup = ''
-    wrapProgram "$out/bin/gnome-session" \
+    wrapProgram "$out/libexec/gnome-session-binary" \
       --prefix GI_TYPELIB_PATH : "$GI_TYPELIB_PATH" \
       --suffix XDG_DATA_DIRS : "$out/share:$GSETTINGS_SCHEMAS_PATH" \
       --suffix XDG_DATA_DIRS : "${gnome3.gnome-shell}/share"\

pkgs/desktops/gnome-3/core/gnome-session/fix-paths.patch

@@ -1,6 +1,22 @@
 --- a/gnome-session/gnome-session.in
 +++ b/gnome-session/gnome-session.in
-@@ -13,7 +13,7 @@ if [ "x$XDG_SESSION_TYPE" = "xwayland" ] &&
+@@ -3,11 +3,11 @@
+ if [ "x$XDG_SESSION_TYPE" = "xwayland" ] &&
+    [ "x$XDG_SESSION_CLASS" != "xgreeter" ] &&
+    [  -n "$SHELL" ] &&
+-   grep -q "$SHELL" /etc/shells &&
+-   ! (echo "$SHELL" | grep -q "false") &&
+-   ! (echo "$SHELL" | grep -q "nologin"); then
++   @grep@ -q "$SHELL" /etc/shells &&
++   ! (echo "$SHELL" | @grep@ -q "false") &&
++   ! (echo "$SHELL" | @grep@ -q "nologin"); then
+   if [ "$1" != '-l' ]; then
+-    exec bash -c "exec -l '$SHELL' -c '$0 -l $*'"
++    exec @bash@ -c "exec -l '$SHELL' -c '$0 -l $*'"
+   else
+     shift
+   fi
+@@ -13,7 +13,7 @@
    fi
  fi