On 8 January 2013 22:29, Christian Tismer <tis...@stackless.com> wrote: > So why is it so difficult to just use "except ValueError as e" ? > > Am I missing the point, or would it not just work with python 2.7 and up?
The problem is that distribute supports Python 2.4 and up. Until they drop support for at least 2.4 and 2.5, they don't stand a chance of moving away from 2to3 to a single-source model (and even then, it's a lot of work for little benefit so they may not want to take that step anyway). It's the 2to3 process that's the issue here. The issue with pip upgrade is then that pip uses distribute as part of the upgrade command, and you hit nasty self-reference problems as documented in pip issue #650. It's only a problem for distribute, not for other projects using 2to3, precisely because pip upgrade relies on distribute to do its work. There may be a workaround which can be added to pip (that would be a fix for issue #650), but it genuinely is a relatively minor issue because: 1. It only affects distribute, not all 2to3-using packages. 2. It's easy enough to work around by doing a manual "setup.py install" style installation of distribute. 3. A certain proportion of people probably just rebuild their virtualenvs if they want to upgrade distribute (I know I do, but it depends on your working practices, I guess). 4. Even if this problem was fixed, using distribute to upgrade itself will probably still not work on Windows, due to the process attempting to overwrite open files (I don't know this for certain, but I suspect it). As far as the question of people's perception of Python 3 goes, I would expect that the explanation that "distribute is a special case because it's part of the machinery used to implement pip upgrade and it can't upgrade itself - you can work around the issue like this (2 above)" would be acceptable to most people - assuming they were not simply looking for an excuse to prefer Python 2. FWIW, I'll try to spend some time looking at #650. I don't expect a complete fix, although at a minimum I would hope that it's possible to do at least some of the following: - add some comments to the documentation - allow the user to specify that pip should never upgrade distribute (issue #654) - never attempt to upgrade distribute due to implicit dependency resolution (i.e., the user has to explicitly specify it on the command line) - raise an error with a better explanation of the issue if the user does attempt to manually upgrade distribute with pip Paul Paul _______________________________________________ Distutils-SIG maillist - Distutils-SIG@python.org http://mail.python.org/mailman/listinfo/distutils-sig
