[Python-Dev] Python-3 transition in Arch Linux (original) (raw)

Thomas Wouters thomas at python.org
Fri Nov 5 09:47:18 CET 2010

On Fri, Nov 5, 2010 at 01:43, Stephen J. Turnbull <stephen at xemacs.org>wrote:

Thomas Wouters writes:

> To clarify (but I dont speak for the rest of #python, just myself), I think > the move was premature, but I don't use Arch and I don't know what typical > Arch users expect. All of the Arch users I know expect Arch to occasionally do radical things because they're the right things to do in the long run. But every avant garde distribution picks up its share of wannabes who don't understand how the process works. > The reason I think it's premature is that 'python2' just doesn't > work everywhere, and I would have gone for a transitionary period > where '/usr/bin/python' is something that screams loudly that it > shouldn't be used before it executes 'python2'. This is unrealistic. It would seriously annoy Arch's intended audience. (Eg, recently I've become a lot more favorable to using Word instead of OOo because Word doesn't pop up a useless warning every time I save a .doc file.) Practically speaking, it would have to be off by default, like Python pending deprecation warnings.

Wait, what? Warning about impending brokenness is more annoying than just plain breaking? How on earth would the warning be "useless"? Keep in mind that the warning would only show up if stuff would otherwise not work.

Anyway, I bet that anybody capable of upgrading their Arch packages

and complaining to #python about resulting breakage would be capable of complaining to #python about the weird warning about python2. And you can't have a NO /USR/BIN/PYTHON topic, can you?

Any change is disruptive. My comment wasn't about the crowd of people visiting #python and complaining, it was about the decision to change /usr/bin/python, and how it was done. However, a warning with a clear description -- for example, a link to a webpage explaining the situation -- would most assuredly have prevented many people from coming to #python in desperation. They might still have complained, in #python or elsewhere, but it would have been a lot clearer.

> As for #python, well, we got this storm of people utterly confused > about how their stuff doesn't work anymore, and putting the blame > in the wrong place. How so? Ultimately, Guido is responsible for this. Sure, the

immediate symptom was caused by Arch's action, but Python 3 is

rather incompatible with Python 2. You're going to get a storm every time a distro changes, and in a year or two, it's no longer going to be something you can dispose of by setting a hotkey to "Google for 'BOGUS Linux python'" -- it's going to be stuff that requires a real understanding of how Python 3 differs from Python 2, and often will be pretty subtle.

> I don't think a distribution should ever cause that (even though > many do in lesser ways)

Sure, and Guido should have exercised the Time Machine a little harder so that Python 3 never needed to happen. IOW, this is the price of success and wide distribution.

No, that's not my point at all. The problem isn't that Python 3 is incompatible with Python 2. The problem is that stuff broke without (apparently) fair warning. This isn't a Python thing, this is a distribution thing: for users of a distribution, having a clear, usable migration path for incompatible changes is important. For users, not packagers, this means you have to slap them in the face with upcoming incompatible changes, or they won't notice. It may not be important for Arch, or for the users Arch expects to have, but it sure as hell is important to me and every sysadmin I know :)

-- Thomas Wouters <thomas at python.org>

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