pantheon.elementary-session-settings: cleanup

pkgs/desktops/pantheon/desktop/elementary-session-settings/default.nix

@@ -62,11 +62,21 @@ let
   '';
 
   executable = writeScript "pantheon" ''
-    export XDG_CONFIG_DIRS=${elementary-settings-daemon}/etc/xdg:${elementary-default-settings}/etc:$XDG_CONFIG_DIRS
+    # gnome-session can find RequiredComponents for `pantheon` session (notably pantheon's patched g-s-d autostarts)
+    export XDG_CONFIG_DIRS=@out@/etc/xdg:$XDG_CONFIG_DIRS
+
+    # Make sure we use our gtk-3.0/settings.ini
+    export XDG_CONFIG_DIRS=${elementary-default-settings}/etc:$XDG_CONFIG_DIRS
+
+    # * gnome-session can find the `pantheon' session
+    # * use pantheon-mimeapps.list
     export XDG_DATA_DIRS=@out@/share:$XDG_DATA_DIRS
+
+    # Start pantheon session. Keep in sync with upstream
     exec ${gnome-session}/bin/gnome-session --builtin --session=pantheon "$@"
   '';
 
+  # Absolute path patched version of the upstream xsession
   xsession = writeText "pantheon.desktop" ''
     [Desktop Entry]
     Name=Pantheon
@@ -115,15 +125,21 @@ stdenv.mkDerivation rec {
   ];
 
   postInstall = ''
+    # our mimeapps patched from upstream to exclude:
+    # * pantheon-mail -> geary
+    # * evince.desktop -> org.gnome.Evince.desktop
     mkdir -p $out/share/applications
     cp -av ${./pantheon-mimeapps.list} $out/share/applications/pantheon-mimeapps.list
 
+    # instantiates pantheon's dockitems
     cp "${dockitemAutostart}" $out/etc/xdg/autostart/default-elementary-dockitems.desktop
 
+    # script `Exec` to start pantheon
     mkdir -p $out/libexec
     substitute ${executable} $out/libexec/pantheon --subst-var out
     chmod +x $out/libexec/pantheon
 
+    # absolute path patched xsession
     substitute ${xsession} $out/share/xsessions/pantheon.desktop --subst-var out
   '';