Why would you garbage-collect older working generations without testing whether the latest works. You'd have to go out of your way to do that, and it goes against the entire purpose of it.
Not every bug manifests itself right after reboot. You can easily have a bunch of generations you just think are ok.
The point is entirely different: if you update the channel-list you need the network for any changes to the configuration and I don't know of a way to go back to an earlier channel state.
> The point is entirely different: if you update the channel-list you need the network for any changes to the configuration and I don't know of a way to go back to an earlier channel state.
`nix-channel` does have a `--rollback` flag to it.
However, I feel that Nix Flakes would allow you a better experience. With nix flakes, the revision of the nixpkgs input is persisted in a lockfile. You could check this file in somewhere, and then getting your working directory back to a known working state is much easier.
This is not a support forum and we're not trying to diagnose and fix someone's issue. It's just not that hard to get into trouble with NixOS and there's still a room for improvement, that's all.
Reading on `nix-channel --rollback`, it should definitely help in some cases and I don't know how I missed it, maybe the docs weren't clear it's not tied to config generations or I just didn't pay enough attention.
The point is entirely different: if you update the channel-list you need the network for any changes to the configuration and I don't know of a way to go back to an earlier channel state.