[SOLVED] Sudden issue with Python installation via Homebrew

Issue

I have Python 3.12 and virtualenv 20.25.0, both installed via Homebrew. The last time I used my computer, virtualenv was functioning properly. The very next time I try to use virtualenv, I am greeted with this error:

> $ virtualenv --version
Traceback (most recent call last):
  File "/usr/local/bin/virtualenv", line 5, in <module>
    from virtualenv.__main__ import run_with_catch
  File "/usr/local/lib/python3.12/site-packages/virtualenv/__init__.py", line 3, in <module>
    from .run import cli_run, session_via_cli
  File "/usr/local/lib/python3.12/site-packages/virtualenv/run/__init__.py", line 7, in <module>
    from virtualenv.app_data import make_app_data
  File "/usr/local/lib/python3.12/site-packages/virtualenv/app_data/__init__.py", line 11, in <module>
    from .read_only import ReadOnlyAppData
  File "/usr/local/lib/python3.12/site-packages/virtualenv/app_data/read_only.py", line 5, in <module>
    from virtualenv.util.lock import NoOpFileLock
  File "/usr/local/lib/python3.12/site-packages/virtualenv/util/lock.py", line 12, in <module>
    from filelock import FileLock, Timeout
ModuleNotFoundError: No module named 'filelock'

The internet happens to not be very helpful and I have done nothing myself in the time between using virtualenv successfully and now. What could've happened here?

Solution

pip install virtualenv installs filelock as a dependency. If Homebrew didn't install filelock it's a bug in its formulas.

Try to fix by installing filelock directly:

sudo python3.12 -m pip install --break-system-packages filelock

If that doesn't help try to upgrade the entire stack of dependencies for virtualenv:

sudo python3.12 -m pip install --break-system-packages --upgrade virtualenv

PS. I often recommend to avoid sudo but this time it's required to fix/upgrade what is installed under /usr/local

Answered By - phd

Answer Checked By - Katrina (WPSolving Volunteer)