Upgrading nix suggest nix upgrade-nix

[lemastero]

Motivation

After attempt to update multi-user Nix on macOS using:

sudo -i sh -c 'nix-channel --update && nix-env -iA nixpkgs.nix && launchctl remove org.nixos.nix-daemon && launchctl load /Library/LaunchDaemons/org.nixos.nix-daemon.plist'

it did not work.

Running:

nix upgrade-nix

solved the problem.

Context

Checklist for maintainers

Maintainers: tick if completed or explain if not relevant

• agreed on idea
• agreed on implementation strategy
• tests, as appropriate
  • functional tests - tests/**.sh
  • unit tests - src/*/tests
  • integration tests - tests/nixos/*
• documentation in the manual
• code and comments are self-explanatory
• commit message explains why the change was made
• new feature or incompatible change: updated release notes

[edolstra]

We should probably remove the old instructions if they don't work. However, I guess nix upgrade-nix does still require launchtl calls. It would be nice if it did that automatically...

[lemastero]

Old instructions did not worked for me. I assume it might be issue specific to my env.
Perhaps old way works for other people 🤔

The docs for nix upgrade-nix say:

Warning
This program is experimental and its interface is subject to change.

That is why I thought adding this as alternative is a good idea.

WDYT @edolstra?

[fricklerhandwerk]

A question I couldn't find an answer for myself, excuse me if this is off topic, but it may be pertinent:

Why does such a command exist in the first place? Is it made for a world where package management is imperative? Because in all of the ecosystem's declarative configuration managers, you'd update your environment to have a newer Nix, symlink that and be done. Or am I badly misunderstanding something?

[nixos-discourse]

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

https://discourse.nixos.org/t/tweag-nix-dev-update-44/25546/1

[fricklerhandwerk]

Triaged in the Nix team meeting 2023-02-17:

• @edolstra: the vast majority of users don't use NixOS
  • @fricklerhandwerk: my point is that probably a vast majority uses some kind of declarative config
• @edolstra: the problem underlying this PR will be resolved will go away when the CLI is stable
  • (vigoruous discussion around what that would entail)
• to discuss in order to clarify underlying issues

[nixos-discourse]

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

https://discourse.nixos.org/t/2023-02-17-nix-team-meeting-minutes-33/25624/1

[fricklerhandwerk]

Discussed in the Nix team meeting 2022-02-27:

• @thufschmitt: nix upgrade-nix is experimental
  • @Ericson2314: but there is no guard on it in the code
• (some philosophising on the notion of self-upgrading)
• @Ericson2314: the manual on installation and upgrading needs general overhaul
  • @fricklerhandwerk: yes, we probably have to address the underlying issues first
• agreement: postponed, this is not a priority

[nixos-discourse]

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

https://discourse.nixos.org/t/2023-02-27-nix-team-meeting-minutes-36/25890/1