wexpect fails in venv

[raczben]

Describe the bug
Wexpect cannot run inside venv. (Note wexpect works inside virtualenv)

To Reproduce
Create...:
python -m venv myvenv

...and activate venv
myvenv\Scripts\activate

Install wexpect:
python -m pip install wexpect

Run any of from wexpect examples:
python examples\hello_wexpect.py

Expected behavior
Not to crash with EOF

Environment:

• Win10.0.18363 Build 18363
• Python 3.7.4
• wexpect version: Doesnt care, wexpect==2.3.6, wexpect==3.1.0

[raczben]

The root-casue will be around process launching.
When the host process starts the console process, gets wring pid. the self.conpid is different than ConsoleReader's os.getpid()
Enable logging, to see more details.

Host's self.conpid matches with ConsoleReader's os.getpid() if wexpect not runs from venv.

[raczben]

This is the root cause.

[akent]

This fix in dev branch seems to work well. Any chance of a new release?

[ddeel]

It looks like this Issue has also turned into a problem for virtualenv...

I ran into a situation where wexpect programs that worked well on a system with an older virtualenv environment do NOT work on systems with newer virtualenv environments. In the newer virtualenv environments, wexpect programs always fail with the same pywintypes.error that says 'The system cannot find the file specified.'

After some debugging, I discovered that wexpect programs still work correctly on all my systems if virtualenv is not used. (But this is not very desirable for me.)

Looking at the virtualenv changelog, I found a note on Release 20.0.34 that says "Align with venv module when creating virtual environments with builtin creator on Windows 3.7 and later"; I'm thinking this means that starting with virtualenv 20.0.34, wexpect no longer works in virtualenv environments, because they'll have the same problem as venv environments.

My current work-around is to simply use virtualenv 20.0.30 for all my wexpect programs. It's not the latest version of virtualenv, but it seems to allow my wexpect programs to continue to work on all my systems, at least for now.

[raczben]

Thank this comment,

The 850eece shows a way to solve this issue in all virtualenv. This implementation does not uses the child process' pid to identify the pip.

[wamsachel]

The 850eece worked for me, thanks!

If anyone needs help, you can use the following cmd inside an activated venv to install the fix:

pip install git+https://github.com/raczben/wexpect.git@dev

[jgentil]

Please release this!

[Stefanhg]

@jgentil I think the package development is completely dead.
I have done a PR which haven't been merged yet.

My conclusion with this is that it does not always work as if you run multi or single user Python install it still breaks. I think the conclusion was with Python multi user install if you don't run cmd in admin it will install packages in AppData because of write permissions to C:/Program files so therefore it will create 2 Python locations which breaks it.

It sucks as I have some CLI things to test on Windows.