Once upon a time there was a user that wanted to install firefox.
The user tried to do
pacman -S firefox but it didn't work. The all
mighty pacman reported that
firefox-3.2.4-1.i686.pkg.tar.gz could not
be found on his mirror. So the user tried
pacman -Sy firefox. It
worked and the user rejoiced since he could once again go and troll /h/.
But all was not good. The user had made a grave error!
See, when the user told the almighty pacman to
-Sy firefox, pacman did
as it was told. It went and checked its databases, found firefox, and
noticed that firefox also wanted a new version of one of its friends,
readline. So the almighty pacman also updated readline.
The problem was that it was that this readline update was no small version bump. Oh no, it was a bump from version 5 to version 6! And this of course also included a .so name bump. But the user was blissfully ignorant to all this. After spending hours trolling /h/ and /d/, he decided to go to bed. Before he went to sleep, he shut down the system because it was quite noisy with all the papst fans running at 6000rpm.
The next morning when the user turned on his system to check what had transpired in /b/ while he was asleep. Instead of getting his hello-kitty gdm login theme he got a horrible message!
error while loading shared libraries: libreadline.so.5: cannot open shared object file: No such file or directory
Because bash (and many other packages) depended on
readline and not
readline<=5.x, bash had not been updated together with readline and
rendered the system unbootable.
The user struggled for hours with the system to no avail. At last he gave up, booted his laptop and went to bbs.archlinux.org. There he proceeded to flame and rant about how horrible of an OS archlinux was and how nøøbish its developers were. To this, the glorious evil overlords on the bbs replied:
PEBKAC. Don't upgrade single packages. Keep your system up to date.