Set a environment variable for venv prompt

[batisteo]

BPO	35328
Nosy	@brettcannon, @vsajip, @asottile, @lysnikolaou, @ZackerySpytz, @tirkarthi, @batisteo, @mafredri
PRs	bpo-35328: Set VIRTUAL_ENV_PROMPT at venv activation #10745 bpo-35328: Set VIRTUAL_ENV_PROMPT at venv activation (GH-21587) #21587 bpo-35328: Always set VIRTUAL_ENV_PROMPT at venv activation #22324

^{Note: these values reflect the state of the issue at the time it was migrated and might not reflect the current state.}

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GitHub fields:

assignee = None
closed_at = None
created_at = <Date 2018-11-27.16:12:29.700>
labels = ['type-feature', 'library', '3.10']
title = 'Set a environment variable for venv prompt'
updated_at = <Date 2020-09-21.18:58:02.565>
user = 'https://github.com/batisteo'

bugs.python.org fields:

activity = <Date 2020-09-21.18:58:02.565>
actor = 'brett.cannon'
assignee = 'none'
closed = False
closed_date = None
closer = None
components = ['Library (Lib)']
creation = <Date 2018-11-27.16:12:29.700>
creator = 'batisteo'
dependencies = []
files = []
hgrepos = []
issue_num = 35328
keywords = ['patch']
message_count = 10.0
messages = ['330533', '330542', '330548', '333043', '342860', '343325', '343327', '343328', '374481', '377175']
nosy_count = 8.0
nosy_names = ['brett.cannon', 'vinay.sajip', 'Anthony Sottile', 'lys.nikolaou', 'ZackerySpytz', 'xtreak', 'batisteo', 'mafredri']
pr_nums = ['10745', '21587', '22324']
priority = 'normal'
resolution = None
stage = 'resolved'
status = 'open'
superseder = None
type = 'enhancement'
url = 'https://bugs.python.org/issue35328'
versions = ['Python 3.10']

[batisteo]

When creating a new virtual env with python3 -m venv .venv --prompt env, the prompt information is only used to set a temporary PS1.

This information is lost when using custom prompt, for example with ZSH.

I propose to set VIRTUAL_ENV_PROMPT=VENV_PROMPT when activating the newly created venv, to be used by tools and other shells.

[asottile]

The current prompt works fine for me on zsh -- what's the bug here?

zsh $ virtualenv venv --prompt '(wat)'
Using real prefix '/usr/local/Cellar/python/3.7.0/Frameworks/Python.framework/Versions/3.7'
New python executable in /private/tmp/venv/bin/python3.7
Also creating executable in /private/tmp/venv/bin/python
Installing setuptools, pip, wheel...done.
zsh $ . venv/bin/activate
(wat)zsh $

[batisteo]

How the venv prompt name would be displayed in a project like Powerline?

Or in VS Code? https://i.ibb.co/JHYrnk2/Screenshot-from-2018-11-27-19-41-47.png

Or in my custom prompt? https://gist.github.com/batisteo/c5c9bd87a344cdbfb7a6401648c118a2#file-batisteo-zsh-theme-L194

[tirkarthi]

bpo-34439 seems like a similar proposal. I am adding @vinay.sajip. Since this seems like a new feature I have removed 3.7 from the version list.

[lysnikolaou]

Is anybody still working on this?

[brettcannon]

@lys.nikolaou it looks like there was an initial PR, but it only updated things for Bash and not for all the other shells that we support for virtual environments.

[lysnikolaou]

@brettcannon, yeah I saw that, but there hasn't been any progress since November. I'm still interested in this though. What would the correct workflow be? Pushing commits to the same PR or opening a new one with a co-author?

[brettcannon]

You can open a new PR with co-author or basing off of their fork if it's still around.

[vsajip]

New changeset c82dda1 by Zackery Spytz in branch 'master':
bpo-35328: Set VIRTUAL_ENV_PROMPT at venv activation (GH-21587)
c82dda1

[mafredri]

I believe #65786 does not fully address this issue because VIRTUAL_ENV_PROMPT is being conditionally set only if VIRTUAL_ENV_DISABLE_PROMPT is unset. Shell prompts must set VIRTUAL_ENV_DISABLE_PROMPT to non-empty to prevent venv from hijacking PS1. I'm one of the maintainers of the Pure prompt for zsh, and it would be great if VIRTUAL_ENV_PROMPT could always be set, just as VIRTUAL_ENV is too.