On Wed, Sep 28, 2022, at 5:08 AM, Svante Signell wrote: > > You can easily revert any system having usrmerge installed with dpkg- > fsys-usrunmess. This should be known by all Debian users, by some > suitable channel.
Having used it myself a couple of times, I would question "easily". If all goes well, yes, you run it and you reboot and you're done, but if all *doesn't* go well you're left having to manually repair a system with important files not existing in *either* their unmerged or their merged location, which may require booting from recovery media. I'd say that if Debian were going to widely advertise the availability of dpkg-fsys-usrunmess, first it ought to be revamped to ensure that it's fully restartable, idempotent, and never, not even transiently, places the system in a state where it cannot boot at least as far as single user mode (in systemd terms, rescue.target, *not* just emergency.target). Of course the exact same criticism applies to convert-usrmerge -- skimming its code just now, it appears to be idempotent and restartable in principle, but if "the system crashes at a really bad time" (to quote its own comments) I think it _could_ leave the system in a state where it cannot boot as far as rescue.target. In fact, see #1020920. zw
