optimus-manager from the AUR would like a word with you then 
tl;dr, whenever a major python update is released, if optimus-manager is not updated or re-built by the user to support it, then during a system restart, your system will become unbootable until you fix the issue. I avoided this issue myself, but the earlier adopters were not so lucky. Thankfully the fix was simple and avoidable once you know what to look out for with updates. If you don’t use optimus-manager, than this is a non-issue, but for myself I’ve migrated to envycontrol in the hopes that I can avoid this issue for the next major python update.