python code static checker
Pylint
_.. _Pylint
: https://pylint.readthedocs.io/
.. This is used inside the doc to recover the start of the introduction
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Pylint is a static code analyser
_ for Python 2 or 3. The latest version supports Python
3.8.0 and above.
.. _static code analyser
: https://en.wikipedia.org/wiki/Static_code_analysis
Pylint analyses your code without actually running it. It checks for errors, enforces a
coding standard, looks for code smells
_, and can make suggestions about how the code
could be refactored.
.. _code smells
: https://martinfowler.com/bliki/CodeSmell.html
.. This is used inside the doc to recover the start of the short text for installation
For command line use, pylint is installed with::
pip install pylint
Or if you want to also check spelling with enchant
(you might need to
install the enchant C library <https://pyenchant.github.io/pyenchant/install.html#installing-the-enchant-c-library>
_):
.. code-block:: sh
pip install pylint[spelling]
It can also be integrated in most editors or IDEs. More information can be found
in the documentation
_.
.. _in the documentation: https://pylint.readthedocs.io/en/latest/user_guide/installation/index.html
.. This is used inside the doc to recover the end of the short text for installation
Pylint is not trusting your typing and is inferring the actual value of nodes (for a
start because there was no typing when pylint started off) using its internal code
representation (astroid). If your code is import logging as argparse
, Pylint
can check and know that argparse.error(...)
is in fact a logging call and not an
argparse call. This makes pylint slower, but it also lets pylint find more issues if
your code is not fully typed.
[inference] is the killer feature that keeps us using [pylint] in our project despite how painfully slow it is.
- `Realist pylint user`_, 2022
.. _Realist pylint user
: https://github.com/charliermarsh/ruff/issues/970#issuecomment-1381067064
pylint, not afraid of being a little slower than it already is, is also a lot more thorough than other linters. There are more checks, including some opinionated ones that are deactivated by default but can be enabled using configuration.
Pylint isn't smarter than you: it may warn you about things that you have
conscientiously done or check for some things that you don't care about.
During adoption, especially in a legacy project where pylint was never enforced,
it's best to start with the --errors-only
flag, then disable
convention and refactor messages with --disable=C,R
and progressively
re-evaluate and re-enable messages as your priorities evolve.
Pylint is highly configurable and permits to write plugins in order to add your own checks (for example, for internal libraries or an internal rule). Pylint also has an ecosystem of existing plugins for popular frameworks and third-party libraries.
.. note::
Pylint supports the Python standard library out of the box. Third-party
libraries are not always supported, so a plugin might be needed. A good place
to start is ``PyPI`` which often returns a plugin by searching for
``pylint <library>``. `pylint-pydantic`_, `pylint-django`_ and
`pylint-sonarjson`_ are examples of such plugins. More information about plugins
and how to load them can be found at `plugins`_.
.. _plugins
: https://pylint.readthedocs.io/en/latest/development_guide/how_tos/plugins.html#plugins
.. _pylint-pydantic
: https://pypi.org/project/pylint-pydantic
.. _pylint-django
: https://github.com/pylint-dev/pylint-django
.. _pylint-sonarjson
: https://github.com/omegacen/pylint-sonarjson
Projects that you might want to use alongside pylint include ruff_ (really fast,
with builtin auto-fix and a large number of checks taken from popular linters, but
implemented in rust
) or flake8_ (a framework to implement your own checks in python using ast
directly),
mypy_, pyright_ / pylance or pyre_ (typing checks), bandit_ (security oriented checks), black_ and
isort_ (auto-formatting), autoflake_ (automated removal of unused imports or variables), pyupgrade_
(automated upgrade to newer python syntax) and pydocstringformatter_ (automated pep257).
.. _ruff: https://github.com/charliermarsh/ruff .. _flake8: https://github.com/PyCQA/flake8 .. _bandit: https://github.com/PyCQA/bandit .. _mypy: https://github.com/python/mypy .. _pyright: https://github.com/microsoft/pyright .. _pyre: https://github.com/facebook/pyre-check .. _black: https://github.com/psf/black .. _autoflake: https://github.com/myint/autoflake .. _pyupgrade: https://github.com/asottile/pyupgrade .. _pydocstringformatter: https://github.com/DanielNoord/pydocstringformatter .. _isort: https://pycqa.github.io/isort/
Pylint ships with two additional tools:
.. _pyreverse: https://pylint.readthedocs.io/en/latest/pyreverse.html .. _symilar: https://pylint.readthedocs.io/en/latest/symilar.html
.. This is used inside the doc to recover the end of the introduction
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We welcome all forms of contributions such as updates for documentation, new code, checking issues for duplicates or telling us
that we can close them, confirming that issues still exist, creating issues because you found a bug or want a feature
_, etc. Everything is much appreciated!
Please follow the code of conduct
_ and check the Contributor Guides
_ if you want to
make a code contribution.
.. _creating issues because you found a bug or want a feature: https://pylint.readthedocs.io/en/latest/contact.html#bug-reports-feedback .. _code of conduct: https://github.com/pylint-dev/pylint/blob/main/CODE_OF_CONDUCT.md .. _the Contributor Guides: https://pylint.readthedocs.io/en/latest/development_guide/contribute.html
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You can place this badge in your README to let others know your project uses pylint.
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:target: https://github.com/pylint-dev/pylint
Learn how to add a badge to your documentation in the badge documentation
_.
.. _the badge documentation: https://pylint.readthedocs.io/en/latest/user_guide/installation/badge.html
pylint is, with a few exceptions listed below, GPLv2 <https://github.com/pylint-dev/pylint/blob/main/LICENSE>
_.
The icon files are licensed under the CC BY-SA 4.0 <https://creativecommons.org/licenses/by-sa/4.0/>
_ license:
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_Please check the contact information
_.
.. _the contact information
: https://pylint.readthedocs.io/en/latest/contact.html
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from the experts who know it best, while seamlessly integrating with existing
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