Hacker News new | ask | show | jobs
by SudoAlex 4061 days ago
Libraries are a problem - it's difficult to switch unless all your dependencies are Python 3 compatible. The only ways to fix it are to either use an alternative, or perhaps to fork or contribute patches to the project - both of which take up valuable time when your code is still functional under 2.7.

I'm currently creating 2.7/3.3+ compatible code in whatever I create, but I'm still deploying to 2.7 hosts. For most of my projects this is due to just one package which has some Python 3 related bugs, so hopefully I can just flick the switch soon and use 3.4.

It's only easy when your project depends on a few popular packages (eg. the top 200 where 86% are currently Python 3 compatible [1]), it's much more difficult if you've got a long list of dependencies.

[1] https://python3wos.appspot.com/
2 comments
mpdehaan2 4061 days ago
Yep, for me, distributions are the biggest thing holding things back right now, because the existing ones are out there, and will be deployed for a long time.

If deploying a .com website, you can control your dependencies completely, and it's much easier than if you are deploying a system that must interact with existing systems the user/customer might have (for instance, management or monitoring apps).

Thankfully that's not a huuuge class of systems, but it's what I typically work with :)

link
aidos 4060 days ago
I suspect most people don't have to deal with that issue (fortunately, because that must suck). Is there not some way of wrapping the entire binary with your distribution? If I was working in that space I think I'd probably choose a different language, if possible.

As you say, it's not a problem for most of us as we get to dictate the platform.

link
anon3_ 4061 days ago
If you're wondering how you can do above / why it's not such a big deal: Python 2.7 has everything you need to write forward compatible code. It gives you all the __future__ dunders, the only extra thing you need is a compat module [1]:

See kaleidoscope of examples:

- https://www.google.com/search?q=site%3Agithub.com+compat.py+...

- https://github.com/search?utf8=✓&q=extension%3Apy+"if+PY2"&t...

[1]: http://lucumr.pocoo.org/2013/5/21/porting-to-python-3-redux/

link