Re: Python 3.4 and ensurepip (rehashed, long)

[Matthias Klose <doko@debian.org>]

Am 21.03.2014 13:23, schrieb Piotr Ożarowski:
> [Barry Warsaw, 2014-03-19]
> > TL;DR: Let's re-enable the ensurepip module in Python 3.4, and possibly
> >     address some usability issues.  We should descend en masse on Montreal and
> >     stage a revolt at Pycon. :)
>
> IMO our ensurepip.py should look similar to this:
>
> | try:
> |     from pip import *
> | except ImportError:
> |     raise Exception('Please ask administrator to install python3-pip package.'
> |                     ' Note that installing packages system-wide using pip is'
> |                     ' considered harmful, please do not report Python related'
> |                     ' bugs in Debian bugtracker if you decide to do that.')
>
> IMO we should warn users that they can^W will break their systems and
> `sudo pip install ...` should raise an exception if
> --i-will-not-blame-debian option is not enabled.

the option name is not longer than --single-version-externally-managed, that 
seems to be wrong.

> FTR:
>
> After a while (10th time I was asked to clean after pip?) the very first
> thing I look for in tracebacks someone sends me is... ".egg" or
> "/usr/local" paths, seriously! It simply started annoying me and I hate
> every single upstream that recommends using sudo irresponsibly.

There are two issues here:

 - there are cases where you want to install extra packages to be
   used by the system python3.  These should never be installed into
   /usr/lib/python3/dist-packages,
   but into /usr/local/lib/python3.x/dist-packages.
   python3-pip should be patched to do that, and we should work with
   upstream to do that as well and not to mess up the system python.

   It might be good to have a mode for pip that tells you that a
   requirement can be fulfilled by a system package.

   Same thing for python2.7 and python-pip.

 - whether to use python3-pip or a freshly downloaded pip.  When using
   pip to install for the system python3, maybe try to use the shipped
   python3-pip.  I have no opinion if another pip is downloaded and
   installed into for environments created by venv or virtualenv.  Some
   package builds use virtual environments, but the population of these
   has to be satisfied by package build dependencies anyway.

Matthias