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

"Martin v. Löwis" martin at v.loewis.de
Mon May 7 22:55:04 CEST 2012

On 07.05.2012 18:35, Carl Meyer wrote:

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.

Sounds fine to me as well.

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.

OTOH, it significantly reduces the burden on Python end users, for whom creation of a venv under a privileged account is a significant hassle.

This being free software, anybody needs to scratch her own itches, of course.

Regards, Martin

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