On NixOS installing any package is the same as reinstalling the operating system. Reinstalling the operating system just took a minute longer because it had to

On NixOS installing any package is the same as reinstalling the operating system. Reinstalling the operating system just took a minute longer because it had to do more downloading. (edit: in theory, I actually bet that the certificates sneakily leak mutable state into the system with the expiry process, i.e. I bet that if I reinstalled the same version of NixOS with the same configuration, I'd get an install that would actually be able to talk to the nixos package servers) But you're right to be worried a little bit, and this is exactly why many people criticize NixOS. In theory it's the most perfect operating system, but in practice it's so complicated that when something's bugged it's really hard to figure out how to recover, and the documentation is not up to the task of educating you on what to do when things are wrong. Also this situation was a bit special because it couldn't talk to the NixOS servers for upgrading (I presume due to an expired root certificate, but I couldn't figure it out), if it was any other problem, I could simply roll back the upgrade process (which would be instantaneous because it doesn't actually remove the old packages when you upgrade).