nixos/wayland: add gtk portal to all applicable compositors

[Frontear]

Description of changes

Most standalone wayland compositors lack a sufficient xdg-desktop-portal implementation. More often than not, their portal contains only screen capture protocols but completely lacks file picker functionality (see: archwiki/xdg_desktop_portal).

Most of the nixos modules used lib.mkDefault [ "wlr" "gtk" ]; as the solution to this, but never actually provided the gtk portal. This PR adds the gtk portal as an entry in the common wayland-session.nix file, enabling support for all compatible compositors.

PS: if this constitutes a release change let me know !

Things done

• Built on platform(s)
  • x86_64-linux
  • aarch64-linux
  • x86_64-darwin
  • aarch64-darwin
• For non-Linux: Is sandboxing enabled in nix.conf? (See Nix manual)
  • sandbox = relaxed
  • sandbox = true
• Tested, as applicable:
  • NixOS test(s) (look inside nixos/tests)
  • and/or package tests
  • or, for functions and "core" functionality, tests in lib/tests or pkgs/test
  • made sure NixOS tests are linked to the relevant packages
• Tested compilation of all packages that depend on this change using nix-shell -p nixpkgs-review --run "nixpkgs-review rev HEAD". Note: all changes have to be committed, also see nixpkgs-review usage
• Tested basic functionality of all binary files (usually in ./result/bin/)
• 24.11 Release Notes (or backporting 23.11 and 24.05 Release notes)
  • (Package updates) Added a release notes entry if the change is major or breaking
  • (Module updates) Added a release notes entry if the change is significant
  • (Module addition) Added a release notes entry if adding a new NixOS module
• Fits CONTRIBUTING.md.

---

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[JohnRTitor]

Perhaps this should be added to the generic Wayland module, @wineee @fufexan thoughts?

[wineee]

If enableWlrPortal is true, setting xdg.portal.extraPortals may conflict

nixpkgs/nixos/modules/programs/wayland/wayland-session.nix

Line 20 in 1331a3c

xdg.portal.wlr.enable = enableWlrPortal;

nixpkgs/nixos/modules/config/xdg/portals/wlr.nix

Lines 53 to 56 in 1925c60

	xdg.portal = {
	enable = true;
	extraPortals = [ package ];
	};

[fufexan]

@JohnRTitor I agree, it would be best to add xdpg for all standalone compositors, which are less likely to come with a complete portal implementation.

[Frontear]

If enableWlrPortal is true, setting xdg.portal.extraPortals may conflict

nixpkgs/nixos/modules/programs/wayland/wayland-session.nix

Line 20 in 1331a3c

xdg.portal.wlr.enable = enableWlrPortal;

nixpkgs/nixos/modules/config/xdg/portals/wlr.nix

Lines 53 to 56 in 1925c60

	xdg.portal = {
	enable = true;
	extraPortals = [ package ];
	};

It won't conflict because list types merge. They will just merge with one another.

[Frontear]

@JohnRTitor I agree, it would be best to add xdpg for all standalone compositors, which are less likely to come with a complete portal implementation.

I don't mind going about implementing this, it definitely makes a lot more sense imo.

[Frontear]

I've rebased and included the new push. Let me know if this is acceptable and if it is I will remove the sway commit. I've only left it at the moment in case changing my PR isn't desirable.

All modules tested as below:

let
  # file exists in root of nixpkgs repo
  self = builtins.getFlake (toString ./.);

  config = {
    programs = {
      # each one tested one at a time, this is here for completion sake
      sway.enable = true;
      wayfire.enable = true;
      wayland.miracle-wm.enable = true;
      cardboard.enable = true;
      river.enable = true;
      hyprland.enable = true;
      labwc.enable = true;
    };
  };
in (self.lib.nixosSystem {
  modules = [
    ({
      nixpkgs.hostPlatform = "x86_64-linux";
      nixpkgs.config.allowUnfree = true;
      nixpkgs.config.allowBroken = true; # needed for cardboard package

      fileSystems."/".device = "nodev";
      boot.loader.grub.devices = [ "nodev" ];
    })
  ];
}).config.xdg.portal.extraPortals

[fufexan]

LGTM, you can remove the sway-specific commit.

[Frontear]

Done, ready for review and merge.

[gallexme]

having both gnome + hyprland enabled causes

outputs.nixosConfigurations.moot-pc.config.xdg.portal.extraPortals
[
  «derivation /nix/store/v04z3wqji8na8vdb749glh944jwcw1s7-xdg-desktop-portal-gnome-46.2.drv»
  «derivation /nix/store/jiv5f9bcv5qgchr8k3ykppwvlb9r10ix-xdg-desktop-portal-gtk-1.15.1.drv»
  «derivation /nix/store/x5pbssd6a9dxn2yj3m8vf3nhgyfjn9z3-gnome-keyring-46.2.drv»
  «derivation /nix/store/4kcmjgvs32lshmr57fgmrjkwy8yx1hin-xdg-desktop-portal-hyprland-1.3.6+date=2024-09-28_7e500e6.drv»
  «derivation /nix/store/q3diw8lfynliqwh3ji68fkh05vkdf40r-xdg-desktop-portal-gtk-1.15.1.drv»
]

and thereby breaking current builds

error: builder for '/nix/store/0winblydr01ml98jiivsp6izbmvhi2ds-user-units.drv' failed with exit code 1;
       last 1 log lines:
       > ln: failed to create symbolic link '/nix/store/f7i38bxf8fwwc111sh3c129p8l1z53j4-user-units/xdg-desktop-portal-gtk.service': File exists

perhaps it should make sure that it won't add existing portals

[JohnRTitor]

Tracked in #345733, the root cause here is GNOME uses a different build of gtk portal, causing it to conflict.