kdePackages.dolphin: File associations do not work on window managers other than Plasma 6

[Treeways]

Nixpkgs version

• Stable (24.11)

Describe the bug

Dolphin's file associations do not appear under window managers other than Plasma 6 (Niri, Hyprland, Wayfire, etc).

Note that with Plasma 6 uninstalled, replaced with libsForQt5.dolphin, the Qt 5 version does show file associations (although much of the file manager is dysfunctional on its own).

Steps to reproduce

1. Install Plasma 6. services.desktopManager.plasma6.enable = true;
2. Install a different WM. programs.niri.enable = true;
3. Log into this WM, open Dolphin, and open any file.

Expected behaviour

When opening files in Dolphin, application suggestions should appear when using a different window manager.

Screenshots

Plasma 6 (Expected)

Niri, Hyprland, Wayfire, etc. (Broken)

Relevant log output

Additional context

I'm running a Wayland-only system, including components like SDDM.

System metadata

(I'm using a small subset of unstable packages.)

>  nix-shell -p nix-info --run "nix-info -m"
 - system: `"x86_64-linux"`
 - host os: `Linux 6.6.90, NixOS, 24.11 (Vicuna), 24.11.717984.ba8b70ee098b`
 - multi-user?: `yes`
 - sandbox: `yes`
 - version: `nix-env (Nix) 2.24.14`
 - channels(root): `"nixos-24.11, nixos-hardware, nixos-unstable"`
 - nixpkgs: `/nix/var/nix/profiles/per-user/root/channels/nixos`

I assert that this issue is relevant for Nixpkgs

• I assert that this is a bug and not a support request.
• I assert that this is not a duplicate of an existing issue.
• I assert that I have read the NixOS Code of Conduct and agree to abide by it.

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[Treeways]

Notify maintainers

@ilya-fedin @K900 @LunNova @mjm @NickCao @SuperSandro2000 @ttuegel

---

Note for maintainers: Please tag this issue in your pull request description. (i.e. Resolves #ISSUE.)

[nixos-discourse]

This issue has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/manually-symlink-files-in-run-current-system/64555/9

[Treeways]

An okay temporary workaround would be to softlink plasma-applications.menu -> applications.menu (courtesy of a fix from KDE Discuss, and @TLATER on Discourse):

environment.systemPackages = let
  # I wish there was a `pkgs.mapLink` or something to do this
  application-menu = pkgs.runCommandLocal "xdg-application-menu" { } ''
    mkdir -p $out/etc/xdg/menus/
    ln -s ${pkgs.kdePackages.plasma-workspace}/etc/xdg/menus/plasma-applications.menu $out/etc/xdg/menus/applications.menu
  '';
in [
  application-menu
]

However, things don't look exactly the same as they would on Plasma 6.
(Top: Dolphin using workaround in Niri WM; bottom: Dolphin in Plasma 6)

I suspect that Plasma 6’s Dolphin notices the category of file, and renders bigger icons accordingly based on items in the category.

[ilya-fedin]

The dialog from the second screenshot looks like xdg-desktop-portal-kde's OpenURI dialog.

[nicobft]

This one-liner fixed it for me:

environment.etc."xdg/menus/applications.menu".source = "${pkgs.kdePackages.plasma-workspace}/etc/xdg/menus/plasma-applications.menu";

Don't forget to nixos-rebuild switch and kbuildsycoca6.

Pretty much the nix way, in my opinion.

@Treeways might be what you were wishing for

[EliteAMDGamer]

environment.etc."xdg/menus/applications.menu".source = "${pkgs.kdePackages.plasma-workspace}/etc/xdg/menus/plasma-applications.menu";

This 100% just fixed it for me thank you so much! its been killing me.

[SuperSandro2000]

Can you try prepending "${pkgs.kdePackages.plasma-workspace}/etc/xdg/menus/plasma-applications.menu" to XDG_CONFIG_DIRS and if that works for you PR it, please?

[SuperSandro2000]

fyi #438914

[EliteAMDGamer]

At the time when its merged will i need to remove environment.etc."xdg/menus/applications.menu".source = "${pkgs.kdePackages.plasma-workspace}/etc/xdg/menus/plasma-applications.menu"; from my configuration?

[SuperSandro2000]

and turn on programs.dolphin.enable

[nixos-discourse]

This issue has been mentioned on NixOS Discourse. There might be relevant details there:

https://discourse.nixos.org/t/hyprland-dolphin-file-manager-trying-to-open-an-image-asks-for-a-program-to-use-for-open-it/69824/3

[tobiasBora]

In KDE plasma, see also #409986