nix-helpers VS impermanence

Yes, to get Nixpkgs it's much faster to use `fetchTarball`.

You're right that `builtins.fetchTarball` is faster than `builtins.fetchGit` (due to the ridiculous amount of commits in the Nixpkgs repo). I like to keep such definitions in a single, company-wide/project-agnostic git repo (what the Nix Pills series calls the "repository pattern"), and have individual projects import them via `builtins.fetchGit`.

Many years ago we didn't have `builtins.fetchGit`, so had to use the 'fetchgit' function from Nixpkgs instead. That created a chicken-and-egg situation if we wanted to take the Nixpkgs version from some other git repo; hence needing to "bootstrap" via `(import { config = {}; }).fetchgit`, and cross our fingers that `NIX_PATH` wasn't set to some crazy value (which, of course, I would inevitably do... https://github.com/Warbo/haskell-te/blob/24475a229908caa3447... )

Note that we need `config = {};` when importing Nixpkgs to avoid an impurity which tries to read files in $HOME. More recent versions of Nixpkgs also need `overlays = [];` to avoid another impurity (looks like this changed at Nixpkgs 17.03, according to https://github.com/Warbo/nix-helpers/blob/master/nixpkgs.nix )

Where nixpkgs2105 is a pinned revision of the Nixpkgs repo, defined in another overlay. My current Nix config has pinned Nixpkgs versions going back to 2016. For example, here's a bunch of such overrides:

https://github.com/Warbo/nix-config/blob/master/overrides/fi...

At the moment I'm using niv to manage the pinned Nixpkgs versions (the 'repoXXXX' entries):

https://github.com/Warbo/nix-helpers/blob/master/nix/sources...

You might want to set up NixOS with impermanence, with something like https://github.com/nix-community/impermanence. Install an easy to use desktop environment like ElementaryOS, and configure NixOS with or without Flatpak, if you want to give the user the ability to install new software or not. Then set up automatic updates, automatic garbage collection and you have a truly stable system.

I would not call these projects unbelievable, but they are neat.

- Opt-in state: https://github.com/nix-community/impermanence and https://grahamc.com/blog/erase-your-darlings/

That way will work - I use the impermanence module which works similarly but allows to hide mounts.

This is indeed a blind spot. Thanks for pointing that out! Silverblue -to my knowledge- doesn't do a lot to address this. Though, 3rd-party tools like Home Manager and the suite of applications developed by the folks over at uBlue might be able to limit this to a minimum. Though I'm not sure if it surpasses NixOS in this regard; for the uninitiated. Though, to my knowledge, this requires special attention and depends on the specifics of the NixOS system in question.

[3]: https://github.com/nix-community/impermanence

I have recently stumbled upon Impermanence - modules to help you handle persistent state on systems with ephemeral root storage, and the concept seems quite nice.

I haven't used it yet but nix-community/impermanence has a home-manager module that might be useful.

Some files in /etc (like saved networks) will still not be managed by NixOS, if you want to have full control over them use Impermanence

{ imports = [ (modulesPath + "/installer/scan/not-detected.nix") "${builtins.fetchGit { url = "https://github.com/NixOS/nixos-hardware.git"; }}/system76" "${builtins.fetchGit { url = "https://github.com/nix-community/impermanence.git"; }}/nixos.nix" ];