This problem is different from the Python issue Zed Shaw wrote about.

In Java, developers will bundle dozens of random .jar files with their application. Other versions of these libraries may exist in a Linux distribution already, but specific Java apps aren't linking to those and carefully documenting how to install all the dependencies (or which ones are optional). Instead, from the distro's point of view, these Java apps are being released with a bunch of binary blobs that may or may not contain bugs that need patching later. Which partly defeats the purpose of package management.

Python programmers don't do this. Distros love Python, which is why so many of their system administration/automation scripts depend on it. This puts some tension between packagers, who use it as a bash/perl replacement, and developers like Zed, who want to treat it like an up-to-date library -- but realize that the Java solution of just bundling the whole thing with the main app is ugly. That tension exists because Python developers haven't run amok the way Java developers have.

I just don't see this being true. In what distro is it stuck at 2.4?

I've come to the conclusion that every language is broken from the point of view of people actually working with the language rather than relying on tools previously written in it. Ruby has broken out of this with rvm, maven kinda-sorta fixes Java but seems to come with a bundle of baggage, virtualenv with your own python build works well enough. CLBuild and QuickLisp, the Haskell Platform and from what I can tell Racket automate a similar approach. I don't know much about the Perl ecosystem, but at a guess I'd say that Perl's backwards compatibility saves it better than most. And this is before you start looking at the code quality and release processes of the libraries packaged in the languages' own distribution mechanisms.

Seriously, unless you're working in C/++, I think it's only worth using the system-bundled languages if you're actually targeting the OS itself. If you're targeting more than one platform, using your own build seems to be the only way to stay sane. If you're only targeting a single platform, unless you're tracking a bleeding-edge-style distro like Arch, you can guarantee that all the fun development is going to be going on somewhere you can't reach.

Luckily, we have checkinstall.

I don't quite understand this. Can't Python 2.5 and 2.6 run scripts that were written for 2.4?