[Mojo]: Env var PIP_REQUIRE_VIRTUALENV will cause `modular install mojo` to fail

[cjrh]

Issue description

Installing mojo will fail if a user has the PIP_REQUIRE_VIRTUALENV=true env var set. Setting this var has been a recommended practice in the Python community for a long time now. I had it in my .bashrc for example.

In addition, after the failure (in "Steps to reproduce") occurs, reinstall will also fail unless $ modular clean is done first.

Steps to reproduce

$ export PIP_REQUIRE_VIRTUALENV=true
$ modular install mojo
# Found release for https://packages.modular.com/mojo @ 0.2.1, installing to /home/caleb/.modular/pkg/packages.modular.com_mojo
# Downloads complete, setting configs...
# Configs complete, running post-install hooks...
ERROR: Could not find an activated virtualenv (required).
modular: error: failed to run python: 

Version Info

- Provide Modular CLI version by pasting the output of `modular -v`

modular 0.1.4 (6b54d308)

- What OS did you install modular CLI on ?


$ uname -a
Linux pop-os 6.4.6-76060406-generic #202307241739~1692717645~22.04~5597803 SMP PREEMPT_DYNAMIC Tue A x86_64 x86_64 x86_64 GNU/Linux

[drunkwcodes]

@cjrh Thank for the tip. I also wish to carry forward python's venv. To the point Modular team willing to implement Mojo venv with me. Thread: https://discord.com/channels/1087530497313357884/1143373527932743721

Things are clearer now. The path setting are witten in modular.cfg in .modular/.

We can try to implement Mojo venv openly now! Even with Python! Hope that os and shutil modules are implemented in mojo soon.

[jackos]

Resolved in nightly release by https://github.com/modularml/mojo/commit/b6776222dbd1e2e72a5e6f772d01b35fee7ea0d9. Mojo now finds libpython using the python executable on the top of PATH

You can test before the official release with modular install nightly/mojo. For environments like vscode codespaces that have a python on the top of PATH without a dynamic libpython.so you can activate a virtual environment to use a different version e.g. the system Python is able to link to a dynamic libpython:

/usr/bin/python3 -m venv ~/venv
source ~/venv/bin/activate

Or alternatively create and activate an environment that comes with libpython like pyenv or conda

Please reopen if you have any further issues.