Hello!

This time, we ran into a puzzling problem while using a conda environment on WSL from PyCharm: the package lists did not match even though it was supposedly the same environment. In this article, we look at the cause and how to fix it.

The Situation

Our development flow was as follows:

1. Create a conda virtual environment in WSL
2. Set that environment as the project interpreter in PyCharm
3. Notice something strange as development progresses

Specifically, the following two lists did not match:

• The list of pip packages shown in PyCharm's project settings
• The list of packages shown by the pip list command after activating the conda environment in WSL

Because these did not agree, we had a problem where packages installed directly from the WSL shell were not recognized by PyCharm.

The usual causes of this kind of problem are that PyCharm takes a little while to pick up changes on the WSL side, or that indexing is lagging—but that was not the cause this time.

A Dangerous "Silent Failure"

The most troublesome aspect of this problem is that no error message is displayed at all. To the user, everything looks perfectly normal, which makes it hard even to notice that a problem exists.

(my_conda_env) user@wsl:~$ conda activate my_conda_env
(my_conda_env) user@wsl:~$ pip install numpy  # Looks like it succeeded!

At first glance, the commands above appear to succeed. The prompt shows (my_conda_env), and the pip command runs without complaint. In reality, however, the package was not installed into the conda environment.

This is an extremely troublesome "silent failure."

You are convinced you are working inside the conda environment, but the actual package installation is happening somewhere else entirely. If you keep developing without noticing, you will later be plagued by inexplicable errors and environment mismatches.

Investigating the Cause

Investigating the environment on the WSL side revealed the root cause:

(qualiteg_ml_dev_env) qualiteg_dev@LLM-Inf-Dev:~$ which pip
/home/qualiteg_dev/.local/bin/pip

Even though the conda environment was activated, the which pip command pointed not to the pip inside the conda environment but to the one in the user's home directory at .local/bin/pip. The pip inside the conda environment is the one that should have been used...

In other words, no matter how many times we ran pip install on the WSL side, packages were being installed not into the conda environment but into the user's .local directory. PyCharm, on the other hand, was correctly using the conda environment's pip—hence the mismatch in package lists.

How to Detect and Verify the Problem

To catch this "silent failure," the following checks proved important.

1. Checking for mismatches with PyCharm
   Compare PyCharm's package list with the output of conda list and pip list in WSL. If they disagree, you should suspect this same kind of problem.

Comparing package lists before and after installation

(my_conda_env) user@wsl:~$ conda list numpy  # before installing
(my_conda_env) user@wsl:~$ pip install numpy
(my_conda_env) user@wsl:~$ conda list numpy  # after installing

If a package you supposedly installed via pip does not show up in conda list, the problem is present.

Checking the path after activating the environment

(my_conda_env) user@wsl:~$ which pip

If the result of this command does not point inside the conda environment (for example, /home/user/anaconda3/envs/my_conda_env/bin/pip), that is a warning sign.

The Problem in the .bashrc File

Wondering why this strange behavior was happening, we examined the

.bashrc file and found a problem in the PATH configuration:

# Problematic .bashrc configuration
export PATH=$PATH:/home/qualiteg_dev/.local/bin
export PATH=~/anaconda3/bin:$PATH

# >>> conda initialize >>>
# !! Contents within this block are managed by 'conda init' !!
__conda_setup="$('/home/qualiteg_dev/anaconda3/bin/conda' 'shell.bash' 'hook' 2> /dev/null)"
if [ $? -eq 0 ]; then
    eval "$__conda_setup"
else
    if [ -f "/home/qualiteg_dev/anaconda3/etc/profile.d/conda.sh" ]; then
        . "/home/qualiteg_dev/anaconda3/etc/profile.d/conda.sh"
    else
        export PATH="/home/qualiteg_dev/anaconda3/bin:$PATH"
    fi
fi
unset __conda_setup
# <<< conda initialize <

export PATH=~/anaconda3/bin:$PATH

There were two problems:

1. .local/bin was added to PATH in the form $PATH:/home/qualiteg_dev/.local/bin, which appended it after the system path
2. There was a duplicate PATH setting after the conda initialize block

As a result, even after activating the conda environment, the pip in the .local/bin directory was taking precedence.

The Impact

This "silent failure" cost us quite a bit of time.

1. An illusory development environment:
   We believed we were working inside the conda environment, but environment isolation was not actually working
   Even though the shell was properly inside the virtual environment, repeated pip install / pip uninstall changed nothing at all on the PyCharm side
   One welcome side effect of all this troubleshooting was that we finally got PyCharm updated to the latest version
   
2. A debugging nightmare
   With no error messages, pinpointing the root cause becomes very difficult. We were plagued by mysterious errors such as "the package I installed is missing" and "the behavior differs even though it's the same environment."

The Fix

To resolve the problem, we took the following concrete steps.

1. Fix .bashrc

Change the order of the PATH settings so that the conda environment's PATH takes precedence:

# Before
export PATH=$PATH:/home/qualiteg_dev/.local/bin

# After (prepend instead)
export PATH=/home/qualiteg_dev/.local/bin:$PATH

Also, delete the duplicate PATH line after the conda initialize block:

# Line to delete
export PATH=~/anaconda3/bin:$PATH

2. Run pip explicitly as a Python module

The safest and most reliable approach is to always run pip in the following form:

python -m pip install package_name

This form guarantees that the pip associated with the currently active Python environment (in this case, the conda environment) is used, preventing environment mismatch problems. Making this a habit makes virtual environment management dramatically more stable.

A Habit of Verifying the Environment Up Front

We had always thought of the WSL environment as a temporary development environment and never managed its setup very strictly, so at some point the .bashrc got rewritten without our noticing. Ideally, before starting a new project, you should make the following verification steps a habit.

1. Consistency check between PyCharm and WSL
   After setting up a new project, install a simple test package and confirm that it is recognized by both PyCharm and WSL.

Environment verification commands (example)

# Activate the conda environment
conda activate my_env

# Confirm that all of the following point inside the conda environment
which python
which pip

# Test install and verify
python -m pip install pytest
conda list pytest

Summary

This "silent failure" when creating a conda environment in WSL and using it from PyCharm was particularly nasty.
Because no error messages appeared, we pushed the project forward without noticing the problem existed, and were later plagued by seemingly inexplicable trouble.

To prevent this kind of problem, make it a habit, after activating an environment, to run which pip to confirm which pip is being used (a verification tool works too), and whenever possible install packages using the python -m pip form.
Also, periodically checking the consistency of the package lists between WSL and PyCharm lets you catch latent problems early.

Python virtual environments are powerful tools, but if the WSL side is managed carelessly, "silent failures" like this one will happen and steal your time—so stay vigilant!