New profile location breaks home-manager

[ncfavier]

Describe the bug

Nix 2.14 (presumably #5226) breaks the home-manager tests: https://github.com/nix-community/home-manager/actions/runs/4301868239/jobs/7499628919#step:8:260

(We're pinned on 2.13 for now, so no emergency)

The relevant code where home-manager seems to assume things about the default profile location is https://github.com/nix-community/home-manager/blob/master/modules/lib-bash/activation-init.sh

Does home-manager need to change, and if so, would those changes be compatible with older versions of Nix?

(I've spent exactly 0 seconds thinking about this, I'm just reporting the problem. 😴)

cc @fricklerhandwerk

Priorities

Add 👍 to issues you find important.

[thufschmitt]

Thanks for opening that.

Also see nix-community/home-manager#2544 (which offers what I think is the best solution to that on the HM side) and NixOS/nixpkgs#218858 .

I'm also working on a patch to provide some best-effort backwards-compatibility, but it's probably not going to be 100% reliable if people decide to tweak things a bit

[fricklerhandwerk]

Discussed in the Nix team meeting 2023-03-23:

• @Ericson2314: Backwards compat seems too painful.

  • @rycee said he doesn't mind the breakage as long as there is clear direction. I think we can provide it, and by deduplicatin the code (as @thufschmitt has been doing), we can be confident in our guidance.

• No disagreement

• @eriscon2314: On the other hand, I worry making the XDG stuff behind a flag will not be clear enough direction

  • this is probably a different conversation

• Discussion on how to adapt nix-collect-garabage -d:

  • decision:
    • Before: Look at all users in /nix/var/nix and garbage-collect profiles
    • After: Look at just the current user in new $XDG_STATE_HOME, but not other users' profiles
      • this is now on master Fix root channels location #8073
  • Look at ~/.nix-profile? Not sure
  • With the new location, trawling through users' home directories seems wrong
  • A sysadmin that needs to e.g. forcably reclaim space could still su each user in a loop to delete old profiles.

• @rycee based on the above, if you want nix-collect-garbage -d to collect the current user's Home Manager generations, you should put them into ${XDG_STATE_HOME-$HOME/.local/state}/nix/profiles.

[nixos-discourse]

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

https://discourse.nixos.org/t/2023-03-23-nix-team-meeting-minutes-43/26758/1

[thufschmitt]

Closing since home-manager isn't impacted by this any more

[nixos-discourse]

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

https://discourse.nixos.org/t/2023-03-31-nix-team-meeting-minutes-45/27002/1

[flokli]

My home-manager still/again seems to be impacted, ran into this when trying to start the home-manager-flokli.service on a new NixOS box.

What's the recommended way forward here? Should I just mkdir /nix/var/nix/{gcroots,profiles}/per-user/flokli from now on, or how is this supposed to work on a new system (Nix 2.17.0)?

[thufschmitt]

@flokli what's your home-manager/Nix version? And what's the exact error you see?

[flokli]

This was home-manager fae8af43e201a8929ce45a5ea46192bbd1ffff18, and Nix 2.17.0.

I didn't set any experimental xdg options in Nix.

The log messages were:

Aug 30 11:55:58 x1 systemd[1]: Starting Home Manager environment for flokli...
Aug 30 11:55:58 x1 hm-activate-flokli[11783]: Starting Home Manager activation
Aug 30 11:55:58 x1 hm-activate-flokli[11783]: Sanity checking Nix
Aug 30 11:55:58 x1 hm-activate-flokli[11783]: Sanity checking oldGenNum and oldGenPath
Aug 30 11:55:58 x1 hm-activate-flokli[11783]: This is a live run
Aug 30 11:55:58 x1 hm-activate-flokli[11783]: Using Nix version: nix-env (Nix) 2.17.0
Aug 30 11:55:58 x1 hm-activate-flokli[11783]: Activation variables:
Aug 30 11:55:58 x1 hm-activate-flokli[11783]:   oldGenNum=231
Aug 30 11:55:58 x1 hm-activate-flokli[11783]:   oldGenPath=/nix/store/05ypwxsrlzbl4kzaj1jnj7abab6p8344-home-manager-generation
Aug 30 11:55:58 x1 hm-activate-flokli[11783]:   newGenPath=/nix/store/rrah84zn1q9z4sf31la52vmilqrpmn73-home-manager-generation
Aug 30 11:55:58 x1 hm-activate-flokli[11783]:   newGenNum=232
Aug 30 11:55:58 x1 hm-activate-flokli[11783]:   genProfilePath=/home/flokli/.local/state/nix/profiles/home-manager
Aug 30 11:55:58 x1 hm-activate-flokli[11783]:   newGenGcPath=/home/flokli/.local/state/home-manager/gcroots/current-home
Aug 30 11:55:58 x1 hm-activate-flokli[11783]:   legacyGenGcPath=/nix/var/nix/gcroots/per-user/flokli/current-home
Aug 30 11:55:58 x1 hm-activate-flokli[11783]: Activating checkFilesChanged
Aug 30 11:55:58 x1 hm-activate-flokli[11783]: Activating checkLinkTargets
Aug 30 11:55:58 x1 hm-activate-flokli[11783]: Activating writeBoundary
Aug 30 11:55:58 x1 hm-activate-flokli[11783]: Activating installPackages
Aug 30 11:55:58 x1 hm-activate-flokli[12120]: installing 'home-manager-path'
Aug 30 11:55:58 x1 hm-activate-flokli[12120]: building '/nix/store/gn83jb0dqdc6i519cjqsqsi9rfmbjdq7-user-environment.drv'...
Aug 30 11:55:58 x1 hm-activate-flokli[12120]: error: opening lock file '/nix/var/nix/profiles/per-user/flokli/profile.lock': No such file or directory
Aug 30 11:55:58 x1 hm-activate-flokli[11783]: Oops, Nix failed to install your new Home Manager profile!
Aug 30 11:55:58 x1 hm-activate-flokli[11783]: Perhaps there is a conflict with a package that was installed using
Aug 30 11:55:58 x1 hm-activate-flokli[11783]: "nix-env -i"? Try running
Aug 30 11:55:58 x1 hm-activate-flokli[11783]:     nix-env -q
Aug 30 11:55:58 x1 hm-activate-flokli[11783]: and if there is a conflicting package you can remove it with
Aug 30 11:55:58 x1 hm-activate-flokli[11783]:     nix-env -e {package name}
Aug 30 11:55:58 x1 hm-activate-flokli[11783]: Then try activating your Home Manager configuration again.
Aug 30 11:55:58 x1 systemd[1]: home-manager-flokli.service: Main process exited, code=exited, status=1/FAILURE
Aug 30 11:55:58 x1 systemd[1]: home-manager-flokli.service: Failed with result 'exit-code'.
Aug 30 11:55:58 x1 systemd[1]: Failed to start Home Manager environment for flokli.