`sudo /nix/nix-installer uninstall` fails due to detecting `nix-darwin`, even though `nix-darwin` was already uninstalled

[mitchmindtree]

Following #149, I thought I'd try to reinstall determinate-nix with --prefer-upstream-nix.

When running the installer again it asks to first "try uninstalling the existing install with /nix/nix-installer uninstall".

I run sudo /nix/nix-installer uninstall, it says "nix-darwin installation detected, it must be removed before uninstalling Nix".

I run sudo darwin-uninstaller, it seems to complete with the following:

Proceed? [y/n] y
setting up /run via /etc/synthetic.conf...
failed to stitch firmlinks and/or create synthetics for root volume (c002) ...
setting up /Applications/Nix Apps...
warning: /Applications/Nix Apps is not owned by nix-darwin, skipping App linking...
setting up pam...
applying patches...
setting up /etc...
setting up launchd services...
configuring networking...
configuring power...
setting up /Library/Fonts/Nix Fonts...
setting nvram variables...
warning: nix-channel is deprecated in favor of flakes in Determinate Nix. See https://zero-to-nix.com for a guide to Nix flakes. For details and to offer feedback on the deprecation process, see: https://github.com/DeterminateSystems/nix-src/issues/34.
warning: selector 'darwin' matched no installed derivations
NOTE: the /run symlink will be removed on reboot
NOTE: The /nix/var/nix/profiles/system* profiles still exist and won't be garbage collected.

Done!

I run sudo /nix/nix-installer uninstall, it again fails with:

% sudo /nix/nix-installer uninstall
 INFO nix-installer v3.13.2
 INFO nix-installer v3.13.2
`nix-darwin` installation detected, it must be removed before uninstalling Nix. Please refer to https://github.com/LnL7/nix-darwin#uninstalling for instructions how to uninstall `nix-darwin`.

I restart the machine in case some daemon is still running or something, alas running sudo /nix/nix-installer uninstall still gives the same error.

I'm about to start reading the source of the uninstaller so I can see exactly what is left over that the uninstaller is not happy with.

I'm mostly sharing to keep track of my progress in case it helps someone else.

[mitchmindtree]

After reading the source I found that it checks for:

  1. darwin-rebuild command - Checks if it exists in your PATH
  2. darwin-option command - Checks if it exists in your PATH
  3. org.nixos.activate-system launchd service - Checks if this system service is still registered

Turns out I had darwin-rebuild installed under the user profile, so even though I had run the full darwin uninstaller, the nix-installer was still picking it up on my PATH.

Possible Solution

I guess an improvement here would be to have the uninstall command give more info about why it still detects nix-darwin so the user doesn't have to read the source.

[cole-h]

Great point. I think there are a few places like this (where we check thing and then error, without describing what we checked). I'll have a little bit of time coming up in the next few weeks that I might try to tackle this in. Otherwise, PRs very welcome!