[docs] [issue18939] Venv docs regarding original python install

Graham Wideman report at bugs.python.org
Fri Sep 6 00:02:40 CEST 2013

New submission from Graham Wideman:


More detail needed regarding the original python environment

The article explains how to use venv to create a new python installation with independent libraries etc, and a means to activate one or another virtual python environment. However, there are some points regarding the original python environment which are cloudy.

(1) After pyvenv, what status does the original python installation have? Does pyvenv turn it into just one of now two or more virtual environments? Or is the original one special? Must it be specifically deactivated in order to activate a (different) virtual environment?

(2) The motivation behind venv seems to be to create virtual enviroments that can be substantially or completely separate from the system site directories or from the original python that pyvenv was run from.  Yet elsewhere the doc discusses how  pyvenv creates a pyvenv.cfg file with a home key pointing back to the originating Python installation, and "sys.base_prefix and sys.base_exec_prefix point to the non-venv Python installation which was used to create the venv."... which suggest that a venv is _not_ independent of its creating Python installation.

It would be helpful to provide some context for this seemingly contradictory information.  Perhaps there are scenarios with differing degrees of independence, in which these pointers back to the originating Python installation may or may not be relevant?

(3) How do you proceed to create virtual environments from scratch when you have no initial python installation, or no python installation of that python version?

-- Hope these suggestions help.

assignee: docs at python
components: Documentation
messages: 197030
nosy: docs at python, gwideman
priority: normal
severity: normal
status: open
title: Venv docs regarding original python install
type: behavior
versions: Python 3.3

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