nixos/xfce4-14: init

[worldofpeace]

Motivation for this change

Based off and completes #37594.

Ideally we would have one xfce module and package set, but things aren't as simple as that.
We have 7af5c81 to prevent both of the modules from being used simultaneously, as I'm assuming this could be dangerous.

The following is a quick summary of the changes between #37594

• enable required DBus services
• LibInput is enabled
• add a polkit authentication agent
• only use xfce4-pulseaudio-plugin for pulseaudio support in panel (the other one was extra)
• use proper package set for network manager packages
• use services.xserver.displayManager.sessionCommands over extraSessionCommands
• configuration for Systemd user services

Lastly we dropped xfce4-mixer because it's abandoned.

Further work/Questions

I haven't resynced the thunar plugins patch, not sure if there's compatible plugins at this version?
And should networkmanager be default enabled?

Things done

Checked in a VM that with this configuration, we could get past the login and at least show the desktop. No glaring issues are apparent to me.

• Tested using sandboxing (nix.useSandbox on NixOS, or option sandbox in nix.conf on non-NixOS)
• Built on platform(s)
  • NixOS
  • macOS
  • other Linux distributions
• Tested via one or more NixOS test(s) if existing and applicable for the change (look inside nixos/tests)
• Tested compilation of all pkgs that depend on this change using nix-shell -p nix-review --run "nix-review wip"
• Tested execution of all binary files (usually in ./result/bin/)
• Determined the impact on package closure size (by running nix path-info -S before and after)
• Ensured that relevant documentation is up to date
• Fits CONTRIBUTING.md.

Notify maintainers

cc @

[worldofpeace]

Dropped the assertion since there's no way to rule that out completely, and synced this with module changes I've made on master.

[jtojnar]

hmm, I forgot to submit this.

[jtojnar]

We should probably move this into a separate module.

[worldofpeace]

Safe coexisting of different xfce (up to their simultaneous run, say one on the attached display and another via xrdp) could be done by adding an option to change ~/.config/xfce4.
Not sure if we have to bring it to nixpkgs

Not sure if it would be worth it, I plan if possible to deprecate the previous version next release.

[worldofpeace]

Added a copy cat test of the one we already have so this can be in the tested jobset.

[romildo]

Tested on a VM. Looks good to me.

[worldofpeace]

The only last case I think we should be concerned about is the closure size vs the older version of xfce.
I'm guessing users of xfce would like things to be lightweight and I'd like to be sure it's still acceptable by that standard.

[worldofpeace]

Are we also sure that with nixpkgs-update it won't send pr's updating things to release candidates/unstable releases? (i.e properly version ignored).

[jtojnar]

For GNOME, I regularly check my packages and flag anything that is unstable. Usually, I catch them pretty soon after they appear in Fedora Rawhide, preventing nixpkgs-update from picking them up. After two release cycles, almost every package related to GNOME platform has an ignore pattern on Repology, so only few infrequently released packages remain to be flagged in the future. I guess something similar will need to be done for Xfce.