I've been traumatized by the automatic upgrade in the past, and am fearful to ever try it again. It seems that there's no transaction logic, and when it fails, it leaves everything broken. Is there some way I can tell whether the upgrade will succeed or not based upon WordPress' ability to overwrite certain files, and whether it can make necessary changes to the database?
I'd love to be able to simply ask WordPress to test the various types of access it needs to upgrade, and then tell me whether or not those tests passed before trying to do the actual upgrade. Any solution that is capable of doing this?