Access `dist-packages` when inside a venv

venv dist-packages site-packages

Source

• https://stackoverflow.com/a/47842938/12780516

• by default, python will only have access to the site-packages directly installed inside a venv

• if we want to access the packages from the (Linux) system’s dist-packages that were installed using the system’s package manager, there are multiple possible ways

  1. set PYTHONPATH to include /usr/lib/python<VERSION>/dist-packages this has the drawback that now the dist-packages take precedence over the site-packages from the venv, thus if we have the same package installed in the venv but with a different (usually more recent) version than in the dist-packages, python will use the one from the dist-packages, which is usually not what we want
  2. create a .pth file in the venv’s site-packages folder that points to the system’s dist-packages this has the advantage, that the venv’s packages will be used first and only if python cannot find a package in the venv, it will go looking into the system’s dist-packages

  echo "/usr/lib/python<VERSION>/dist-packages" > .venv/lib/python<VERSION>/site-packages/dist-packages.pth

  (the <VERSION> has to match, of course, so for Python 3.10, for example, this would read python3.10 in both cases)