Update Pantheon to version 7

[bobby285271]

Tracking issue for Pantheon 7 (see #121847 for Pantheon 6).

Visit the project board for lists of random notes that needs attention and this page for lists of upstream updates that needs review.

cc @NixOS/pantheon

FAQ

Feel free to add more if you can edit this issue.

Can we have Pantheon 7 in NixOS 23.05?

If upstream can then we can.

Merge time for #130380 sounds too long for me, can updates happen faster?

Some updates need to be addressed together (see the project board), I try to split updates into small PRs when the update harmonize with existing parts well. We always merge things when it is ready.

How to test a Pantheon update?

For flake users, you can try https://github.com/bobby285271/test-pantheon.

For non-flake users, use:

$ env NIX_PATH=nixpkgs=/path/to/nixpkgs:nixos-config=/path/to/configuration.nix nixos-rebuild build-vm

Do not forget to adjust the path to the nixpkgs checkout /path/to/nixpkgs and the configuration /path/to/configuration.nix.

Why don't handle the following error for me?

Failed assertions:
- You have set services.power-profiles-daemon.enable = true;
which conflicts with services.tlp.enable = true;

I am following what is done in GNOME. We have no way of knowing which way a user wants to resolve the conflict.

• To disable tlp: services.tlp.enable = false;.
• To disable power-profiles-daemon: services.power-profiles-daemon.enable = false;.

Why granite 7 is packaged as a separate package?

In short, granite 6 is for GTK3 apps and granite 7 is for GTK4 apps. I don't really have the time and knowledge to port the world to GTK4.

Why Mutter and GSD 42?

42 is shipped in ubuntu 22.04 and elementary OS 7. While things build with 43+, bumping mutter can cause regressions on gala and when that happens upstream is not likely going to address it before OS 8. We will default to 43+ only when we are confident enough.