unfortunate /etc/passwd.pacnew experience leading to broken system

Description:

I ran pacman -Syu today and the "filesystem" package was updated to 2024.01.19-1, and a /etc/passwd.pacnew file was created containing only the user entry for the "root" user ( which is the state /etc/passwd is in since 8a443108 )

I didn't see any news items regarding this: https://archlinux.org/news/

So I naively replaced /etc/passwd with /etc/passwd.pacnew and rebooted, taking me to an unusable system with systemd/kernel boot logs spammed with "[FAILED] Failed to start Authorization Manager"

I was able to recover my system by booting from an installer USB, arch-chrooting in, and running systemd-sysusers

I'm mostly filing this issue so that others can find it if they end up in a similar state

I'm not really sure what could be done better here...

A news post warning users about this?

A pacman/alpm hook that automatically deletes /etc/passwd.pacnew and re-runs systemd-sysusers when appropriate? 🤷