[Python-Dev] PEP 405 (pyvenv) and system Python upgrades

[Carl Meyer]

On 05/07/2012 03:52 AM, "Martin v. Löwis" wrote:
>> 3) Symlink the interpreter rather than copying. I include this here for
>> the sake of completeness, but it's already been rejected due to
>> significant problems on older Windows' and OS X.
>
> That sounds the right solution to me. PEP 405 specifies that bin/python3
> exists, but not that it is the actual Python interpreter binary that is
> normally used. For each target system, a solution should be defined that
> allows in-place updates of Python that also update all venvs automatically.

I propose that for Windows, that solution is to have a new enough 
version of Windows and the necessary privileges, and use the --symlink 
option to the pyvenv script, or else to manually update venvs using 
pyvenv --upgrade.

> For example, for Windows, it would be sufficient to just have the
> executable in bin/, as the update will only affect pythonXY.dll.
> That executable may be different from the regular python.exe, and
> it might be necessary that it locates its Python installation first.

This sounds to me like a level of complexity unwarranted by the severity 
of the problem, especially when considering the additional burden it 
imposes on alternative Python implementations.

Carl