Re: Patch now available
Yes, well, it was fast but according to reports it also broke SMB sharing between High Sierra machines.
The workaround is (drum roll) to use sudo at the command line to run some obscure utility in libexec.
It seems to me not so much a lack of testing—probably testers would never have thought of that anyway—but someone monkeying around in the code without having a deep understanding of how it works.
High Sierra was supposed to be a maintenance/performance release, with a new filesystem and window manager. It's hard to see how any of the touted changes could have required messing around with the login logic. Someone needs to put an iron fist down and limit the changes in each release to what's necessary, and in particular to forbid random reimplementations of modules just because they're not in Swift or not yet common to iOS.