Python 3.8 brought the capability to put Python cache files under __pycache__/ anywhere. Control this behavior by setting the PYTHONPYCACHEPREFIX environment variable.

Example

• Windows: set environment variable PYTHONPYCACHEPREFIX to %temp%
• MacOS: export PYTHONPYCACHEPREFIX=/tmp
• Linux: export PYTHONPYCACHEPREFIX=/tmp

Workaround

Python older than 3.8 can avoid writing .pyc files anywhere by setting environment variable:

PYTHONDONTWRITEBYTECODE=1