And I thought it's time for me to upgrade to Python 2.5, partly due to a particular masked package and partly due to the fact that I had the itch to upgrade that particular package. So I gone ahead to doing that, happy that it's successful, and sort of left it there for a few days.
A few days later, I do the oh-so-routine of "emerge -uD world" and expect it to run smoothly, only to be proved wrong when emerge start to act up on me. One of the most prominent errors being "ACCESS VIOLATION SUMMARY" in big red text before the emerge fails. Then some of them seemed to have problems with xml2po.
Apparently when python is upgraded, python packages and a couple of programs that relies on it needs to be updated as well. This can be done by executing "python-updater" right after you do the release update of python. And later do the re-emerging of gnome-doc-util, just to be on the safe side.
Currently these steps weren't officially documented in Gentoo and the mention of it is in the GNOME 2.12 upgrading guide. But then again, Python 2.5 is still under the unstable flag, so such inconveniences was expected. Hopefully by the time when the maintainers believe Python 2.5 is ready for prime time (i.e. become "stable") they will issue a notice in the Gentoo newsletter or something.
[P/S: Still haven't got around unmerging Python 2.4 though, but probably I'd do that later]