Right on the heels of version 2.8, we will be seeing a WordPress 2.8.1 release soon. There are several minor bugfixes in so far, mostly dealing with tweaks to plugin and menu management. But the big problem driving a quick update is a bug in the core upgrade feature. It seems that in the case where the upgrade can’t be completed for some reason, the upgrade feature was deleting the wrong files when it attempted to clean up. Oops!
On the bright side, when this did happen, it would only delete files that are part of the core package, not any of your plugin or theme files. So the failure could be fixed pretty easily, by just manually re-installing the 2.7.1 or 2.8 files from a zip archive. [...]
Bug Chasing
Okay, so in my post about Code Spelunking I mentioned about how working on a project can lead you to explore the code because you need to become more familiar with how the code works. But it can also lead you to explore the code to figure out why code doesn’t work. In this particular case, I spent many hours puzzling over why something didn’t work correctly, chasing down the root cause, and eventually finding a bug in the WordPress core. [...]