pylint-venv

Pylint does not respect the currently activated virtualenv if it is not installed in every virtual environment individually. This module provides a Pylint init-hook to use the same Pylint installation with different virtual environments.

Installation

pip install pylint-venv

Add the hook to your Pylint configuration. See the section below corresponding to the type of configuration file you use.

Configure with pyproject.toml

Add the following to your pyproject.toml:

[tool.pylint.MAIN]
init-hook = """
try: import pylint_venv
except ImportError: pass
else: pylint_venv.inithook()
"""

Configure with .pylintrc

Add the following to your .pylintrc:

[MAIN]
init-hook=
    try: import pylint_venv
    except ImportError: pass
    else: pylint_venv.inithook()

If you add this to your ~/.pylintrc in your home directory, it will be applied to all projects by default.

Usage

The hook will then be used automatically if

• a virtualenv without pylint is active,
• or a Conda environment without pylint is active,
• or no environment is active but your CWD contains virtualenv directory.

Anything listed in the PYLINT_VENV_PATH environment variable is considered a virtualenv directory. The default, if the variable is unset, is .venv. Use a colon (:) as path separator. Example for checking directories .venv and .virtualenv:

PYLINT_VENV_PATH=.venv:.virtualenv

You can also call the hook via a command line argument:

$ pylint --init-hook="import pylint_venv; pylint_venv.inithook()"

This way you can also explicitly set an environment to be used:

$ pylint --init-hook="import pylint_venv; pylint_venv.inithook('$(pwd)/env')"

If pylint itself is installed in a virtualenv, then you can ignore it by passing force_venv_activation=True to force the activation of a different virtualenv:

$ pylint --init-hook="import pylint_venv; pylint_venv.inithook(force_venv_activation=True)"

This will try to automatically detect virtualenv and activate it.

Troubleshooting

General

pylint_venv fails to import

Most likely pylint-venv is not installed in the same virtual environment as pylint. Either make sure to ensure pylint-venv into the same virtual environment as pylint, or add the appropriate path in the init hook:

import sys
sys.path.append("/path/to/installation/folder/of/pylint_venv")

pylint_venv breaks parsing with tools

When tools call pylint with -f json, an extra line may break the parser, as the output is no longer valid json. To avoid printing "using venv ...", pass quiet=True to inithook

$ pylint -f json --init-hook="import pylint_venv; pylint_venv.inithook(quiet=True)"

Virtual environment does not get used (installed modules are reported as 'unable to import')

Most likely the virtual environment does not get activated because pylint itself runs in a virtual environment. You can force the activation of the virtual environment with the force_venv_activation=True flag to the pylint_venv.inithook function.

Homebrew

Homebrew installs pylint into a separate virtual environment, thus you will need to set the force_venv_activation=True flag. This also means, that pylint_venv will be in a different search path and you must add the proper path to sys.path. You can use the following configuration adjusted to your Python version:

[MAIN]
init-hook=
    import sys
    sys.path.append("/usr/local/lib/python3.8/site-packages")
    try: import pylint_venv
    except ImportError: pass
    else: pylint_venv.inithook(force_venv_activation=True)