nixos/flatpak: pass system icons and fonts

[io12]

Fixes #119433

Description of changes

Add another patch to Flatpak that mounts the NixOS system font and icon directories into the sandbox if the standard FHS ones don't exist. The FHS paths are still checked so that the Flatpak build still works on non-NixOS systems. Since these directories contain symlinks into /nix/store, the patch also walks the tree of symlinks to collect a list of /nix/store paths to expose to the sandbox.

Also, change the default for fonts.fontDir.enable from false to services.flatpak.enable.

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/)
• 23.11 Release Notes (or backporting 23.05 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.

[jtojnar]

This will not handle symlinks pointing to trees of symlinks (e.g. when using font collections produced with buildEnv) but I am not sure how common that is.

I also wonder about performance with large font libraries. I thought about using nix-store --query --references but that will not work for the /run/current-system paths directly, since they are not in Nix store. It would also pull in all dependencies, not just those referenced by icons/fonts. But I guess we can just address it by having NixOS generate /run/current-system/sw/share/nix-flatpak/fonts.closure if/when someone notices a performance degradataion.

[io12]

Thanks for the review! I applied the suggestions.

This will not handle symlinks pointing to trees of symlinks (e.g. when using font collections produced with buildEnv) but I am not sure how common that is.

I think it does, because get_nix_closure() is recursive. I think I remember this being a requirement for icons.

[andrevmatos]

I'm running this locally, it seems to work fine, at least for fonts (I can see my system fonts in Inkscape without the bindfs workaround).
cursors though seems to work in some apps, and fallback to a black cursor in Gtk3+ ones, not sure if something with this patch or my local config (KDE, cursors set in Plasma and Gtk configs to Oxygen White)

[io12]

I'm running this locally, it seems to work fine, at least for fonts (I can see my system fonts in Inkscape without the bindfs workaround). cursors though seems to work in some apps, and fallback to a black cursor in Gtk3+ ones, not sure if something with this patch or my local config (KDE, cursors set in Plasma and Gtk configs to Oxygen White)

Does the bindfs workaround have the same behavior? If no, what is the output of flatpak --user override --show?

[andrevmatos]

After some restarts (maybe cleaning up the old /usr bindfs mounts), and checking again, this patch seems to be working fine. I can see fonts everywhere, and proper cursors in most apps (but a few stubborn gtk ones, but would not make an issue for them). LGTM

[AndreiSva]

will this fix the mouse cursor not being the adwaita theme in flatpak apps?

[io12]

will this fix the mouse cursor not being the adwaita theme in flatpak apps?

Yes

[nixos-discourse]

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

https://discourse.nixos.org/t/prs-ready-for-review/3032/3158

[beh-10257]

since well this is still an open issue is passing themes as well out of the question

[io12]

since well this is still an open issue is passing themes as well out of the question

I don't think flatpak tries to pass themes by default, just fonts and icons. I also don't know if nixpkgs would be willing to accept a patch to add a feature that doesn't exist on other distros like that?

[beh-10257]

This is what I used to do on arch symlink th theme I want to use from /usr/share/.../themes
To .local/share/themes
And yeah that's enough obv after allowing flatpaks to read
.local/share/themes directory

it seems just installing the package isn't enough in nixos or home-manager since I have no idea where are the themes even stored
Also since well I don't mean make it by default but having the option would just be nice

Also so adding icon packs to .local/share/icons manually isn't gonna pass them ??
Even with this pull request

[AndreiSva]

what is blocking this pr?

[alois31]

I can confirm this fixes icons and fonts in Flatpak apps on my system. The changes also look sane to the extent I can say that without familiarity with glib code.

[beh-10257]

So this will get merged now ??

[alois31]

So this will get merged now ??

No, this has to be done by someone with commit rights. Please be more patient.

[Henry-Hiles]

LGTM

[andrevmatos]

@SuperSandro2000 could you please give a look at this PR? I've been running it for months with great success.

[Ramblurr]

Works for me too!

[SuperSandro2000]

LGTM but I have no clue about the C code :/

[beh-10257]

@andrevmatos can you post just the bit when you overrided the module with this pr
since its been 3 months and there is no guarantee that this will be merged anytime soon I wanna check it out

[andrevmatos]

@beh-10257 my system is a flake using https://github.com/gytis-ivaskevicius/flake-utils-plus, and I use the channels.<name>.patches functionality of it to apply arbitrary PRs to my system's nixpkgs (tracking nixos-unstable-small).

[SuperSandro2000]

@ofborg build flatpak

[RAVENz46]

Fonts fine but icons are still missing.
Is this because I installed icons via home-manager?

Edit: Install icon system-wide solve issue.

[SadSock]

How to apply this patch in nixos 23.11?