Python 3.0 is incompatible with Python 2.0

Python 3.0 is incompatible with Python 2.0

Jesse Noller wrote:

I hate slashdot: Python 3000 is incompatible?!!!

and then says:

A sensationalist title, summary and normal slashdot commenters: "Python 3.0 To Be Backwards Incompatible"

I don't see how the title is sensationalist. Python 3.0 is backwards incompatible with Python 2.0. Conversion scripts are supplied, but that fundamental reality stands. The summary on Slashdot is this:

Organizations using Python will be affected in a major way by changes in store for the language over the course of the next twelve months, Linux.conf.au attendees were told this morning. The Python development community is working towards a new, backwards-incompatible version of the language, version 3.0, which is slated for release in early 2009. Anthony Baxter, the release manager for Python and a senior software engineer at Google Australia, said "We are going to break pretty much all the code. Pretty much every program will need changes." Baxter also added another tidbit for attendees, saying that Python accounts for around 15 percent of Google's code base."

I don't see anything sensationalist in this either. It's true: organizations and communities using Python are going to be impacted in a major way by the release of Python 3.0, and the reason they are going to be impacted is the non-backwards incompatibility. There are significant consequences for organizations that need to deal with this transition - for the organizations that go ahead and make it, and also for the organizations that wait and see and continue to use the Python 2.x version.

I haven't read any of the Slashdot comments. I'm sure some of them are very wrong, and very annoying; that's normal. It's just that I object to spreading the idea that this message is sensationalist or somehow wrong. It's not. It's the reality that one way or another the Python community will have to deal with. Objecting to an expression of this reality spreads the wrong message.

Recognizing that Python 3.0 is backwards incompatible makes us aware that we are heading for something we will have to deal with one way or another. It's a useful wakeup call for people who might not be aware of this.

The language developers are working on a migration script and are adjusting the Python 2.x line of Python so that we can prepare our code bases. By all means, spread that news too in addition to the backwards incompatibility news. But don't object if news sources forgo such subtleties in spreading the main message to take home about Python 3.0: without special action on your part, your code will break when you try to run it with the new interpreter. Adopting Python 3.0 as a community will mean an awful lot of code to transition. It'll be a process of years, and it won't be easy.

(as an aside: I think I wrote a reasonable posting about Python 3.0 just now. Of course that's what I thought when I posted about this last time, and then I had people land on my head like a ton of bricks. It left a very unpleasant taste in my mouth. Let's hope this time will be better. I think having an open discourse about this is important.)