pkgutil.ImpImporter AttributeError in Python 3.12

Problem Statement

When installing Python packages (especially scientific libraries like pyspedas) using Python 3.12, you may encounter the following error:

AttributeError: module 'pkgutil' has no attribute 'ImpImporter'

This commonly occurs during pip install operations in new virtual environments or fresh Python 3.12 installations. The error appears because Python 3.12 removed long-deprecated symbols including pkgutil.ImpImporter from its standard library, as noted in the Python 3.12 release notes.

The root causes are:

1. Outdated setuptools in virtual environments (venv no longer pre-installs setuptools since Python 3.12)
2. Package dependencies incompatible with Python 3.12
3. Presence of old Python paths in PYTHONPATH
4. Missing system dependencies for package compilation

Recommended Solutions

Solution 1: Upgrade setuptools and pip in the virtual environment

The most reliable fix is updating setuptools and pip in your environment:

1. Create and activate virtual environment:

   python -m venv myenv
   source myenv/bin/activate        # Linux/macOS
   myenv\Scripts\activate           # Windows

2. Upgrade foundational tools:

   python -m ensurepip --upgrade
   python -m pip install --upgrade setuptools pip

3. Install your package:

   python -m pip install pyspedas

Why this works

Python 3.12 venvs no longer include setuptools by default. The old pkgutil.ImpImporter reference in outdated setuptools versions triggers the error. Upgrading resolves the compatibility issue.

Solution 2: Pin compatible package versions

If dependencies fail due to Python 3.12 incompatibility, pin specific versions:

python -m pip install numpy==1.26.4  # Required version for 3.12 compatibility
python -m pip install pyspedas

Package Compatibility

Many scientific packages require recent versions for Python 3.12 support. Key version requirements:

• numpy>=1.26.4
• pandas>=2.1.0
• setuptools>=68.0.0

Solution 3: Clean environment variables

Conflicting environment variables like PYTHONPATH can trigger this error. Resolve by:

1. Windows: Remove conflicting paths in System Properties → Environment Variables

   # Check current PYTHONPATH
   echo %PYTHONPATH%
   
   # Clear temporarily (in current session)
   set PYTHONPATH=

2. Linux/macOS:

   unset PYTHONPATH  # Clear temporarily

3. Verify no conflicting paths remain before installing packages

Solution 4: Install system dependencies (Linux)

For Linux systems, install Python development headers:

sudo apt update
sudo apt install python3.12-dev

Then proceed with upgrading setuptools and pip.

Solution 5: Use a compatible Python version

If dependencies lack 3.12 support, use an earlier Python version:

# Windows example: install Python 3.11
py -3.11 -m venv myenv
.\myenv\Scripts\activate
pip install pyspedas

# Linux example
sudo apt install python3.11
python3.11 -m venv myenv

For Conda Users

Conda avoids these issues by managing compatible environments:

conda create -n pyspedas_env python=3.10
conda activate pyspedas_env
conda install -c conda-forge pyspedas

Explanation of the Error

The pkgutil.ImpImporter attribute was a legacy component of Python's import system that was removed in Python 3.12 after years of deprecation. Packages using outdated build tools attempt to access this removed symbol during installation, causing the failure.

Key points:

• Virtual environments in Python 3.12 intentionally omit setuptools to reduce attack surface
• Packages and tools depending on Python's deprecated internal APIs will fail
• The error traces back to pkg_resources/__init__.py attempts to access pkgutil.ImpImporter

Additional Best Practices

1. Always upgrade pip/setuptools first in new Python 3.12 environments
2. Use virtual environments instead of global installs
3. Check package release notes for Python 3.12 compatibility
4. Report incompatibilities to package maintainers

By understanding the changes in Python 3.12's import system and following these solutions, you can resolve installation errors related to removed legacy features.

Production Note

For production systems, consider:

• Locking dependency versions in requirements.txt
• Testing upgrades in isolation first
• Using Docker containers for environment consistency