python -m venv <dir> cause dir appairs more than one times in $PATH

[quchunguang]

Bug report

Bug description:

pwd # /home/qcg/py
python3 -m venv .
source bin/activate # or relogin the shell

import os

envs = os.environ['PATH'].split(':')
envs.sort()
print('\n'.join(envs))
#...
#/home/qcg/py/bin
#/home/qcg/py/bin
#...

my fix:
In bin/activate,

PATH="$VIRTUAL_ENV/bin:$PATH"
export PATH

===>

case ":${PATH}:" in
    *:"$VIRTUAL_ENV/bin":*)
        ;;
    *)
        export PATH="$VIRTUAL_ENV/bin:$PATH"
        ;;
esac

Tested on Ubuntu 24.04 (in Windows WSL2) with built-in python 3.12.3.

CPython versions tested on:

3.12

Operating systems tested on:

Linux

[gaogaotiantian]

I believe for the common use cases, you should not create your venv in an existing directory. So for normal usage, it won't be an issue.

Even if you are doing what you did, I think it's still valid to put the path at the front. Because

• It won't break anything and it's not uncommon to have duplicate paths.
• More importantly, order of paths matters. Even if the directory already exists and it's already in the path, moving up its priority still is a meaningful and useful operation.