nix-darwin: hide trampolines in /Applications, status message for darwin-rebuild

[christian-burger]

Not sure if that's only happening on my system or no one else is a tiny bit annoyed about that 😅 … but on my system there are always two almost identical folders in /Applications.

I think one folder suffices. So I hid the trampolines with chflags. One could make this hiding of the folder optional and an option in the cli-tool and nix-darwin configuration. But I don't see a reason why, since the intent of the "mac-app-util" is to make it available to Spotlight et al. And that's done, even if the folder is being hidden. 🤷

And while I was at it, I added a message about what's happening for when nix-darwin rebuilds the system.

By submiting this PR, I agree to license this contribution under Creative Commons’ CC0 license.

[hraban]

I respect the choice, though on first thought I don't think I will mainline this, in the spirit of "explicit is better than implicit". The two folders are fundamentally distinct and the distinction is important. But I can see the appeal.

[christian-burger]

Maybe, I could convince you to integrate the patch, when I make it an option in the configuration as proposed? And the default to not hide the folder? So, nothing would change for people not explicitly configuring this setting. Does that work with your idea of "explicit is better than implicit"?

[hraban]

Out of curiousity, can you try adding your configuration using lib.mkAfter? E.g.:

  system.activationScripts.postActivation.text = lib.mkAfter ''
    if [[ -d "/Applications/Nix Trampolines" ]]; then
      chflags hidden "/Applications/Nix Trampolines"
    fi
  '';

[christian-burger]

Thanks. lib.mkAfter would work. And if you cannot merge my PR, I’d do either that or merge/rebase onto your changes as I am doing now. I’ve updated the PR: I made it configurable and nothing changes for people not explicitly activating the option.