hyprland-wiki/pages/Nix/XDG-Desktop-Portal-Hyprland.md

xdg-desktop-portal-hyprland (xdph) is a fork of xdg-desktop-portal-wlr (xdpw), which supports window sharing and region sharing (currently broken), apart from output (per-screen) sharing.

Due to the internal workings, xdph depends on the Hyrpland package for getting the window list. However, we cannot make a cross-dependency betwen the Hyprland flake and the xdph flake.

The best solution we found to make everything work properly was to override the Hyprland package that xdph builds with.

In the Hyprland flake, it's done like this:

xdg-desktop-portal-hyprland = inputs.xdph.packages.${prev.system}.default.override {
  hyprland-share-picker = inputs.xdph.packages.${prev.system}.hyprland-share-picker.override {inherit hyprland;};
};

A similar override is being done inside the NixOS module, which means you don't have to tinker with it if you use the module.

If you don't use the module, you will want to do a similar override in your configuration.