Path with no GC roots not being garbage collected

[Gabriella439]

Describe the bug

Nix refuses to garbage collect a path with no garbage collection roots

Steps To Reproduce

$ nix-store --delete /nix/store/kazyfiacq0mfcaqy28c4micglqxw9fhb-nixos-system-nixos-22.11.20220918.f1a49e2
finding garbage collector roots...
0 store paths deleted, 0.00 MiB freed
error: Cannot delete path '/nix/store/kazyfiacq0mfcaqy28c4micglqxw9fhb-nixos-system-nixos-22.11.20220918.f1a49e2' since it is still alive. To find out why, use: nix-store --query --roots

$ nix-store --query --roots /nix/store/kazyfiacq0mfcaqy28c4micglqxw9fhb-nixos-system-nixos-22.11.20220918.f1a49e2

$ # No output from the prior command

Expected behavior

I expected the path to be garbage collected since there are no garbage collection roots protecting the path.

Additional context

$ nix --version
nix (Nix) 2.11.0

The relevant parts of my Nix configuration are:

$ nix show-config
…
keep-derivations = true
…
keep-outputs = false
…

I also verified that there were no temp roots associated with the path either. The only thing in /nix/var/nix/temproots was /nix/var/nix/temproots/30015 which contained this:

/nix/store/hy04g0cmmsvkwabwas03d7kjv1y40pd9-source^@/nix/store/ln3h4rn8hfmn7jdlwqffixi8611zj90n-source^@

I also tried restarting the nix-daemon and trying again.

The problem still remains but it is not urgent to fix, so I can let it stay this way and run additional commands to debug things further if that helps.

[ncfavier]

Possible duplicates: #6135 #6141 #7053