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.. -*- coding: utf-8 -*-
How To Write a Pylint Plugin
============================
Pylint provides support for writing two types of extensions.
First, there is the concept of **checkers**,
which can be used for finding problems in your code.
Secondly, there is also the concept of **transform plugin**,
which represents a way through which the inference and
the capabilities of Pylint can be enhanced
and tailored to a particular module, library of framework.
In general, a plugin is a module which should have a function ``register``,
which takes an instance of ``pylint.lint.PyLinter`` as input.
A plugin can optionally define a function, ``load_configuration``,
which takes an instance of ``pylint.lint.PyLinter`` as input. This
function is called after Pylint loads configuration from configuration
file and command line interface. This function should load additional
plugin specific configuration to Pylint.
So a basic hello-world plugin can be implemented as:
.. sourcecode:: python
# Inside hello_plugin.py
from typing import TYPE_CHECKING
import astroid
if TYPE_CHECKING:
from pylint.lint import PyLinter
def register(linter: "PyLinter") -> None:
"""This required method auto registers the checker during initialization.
:param linter: The linter to register the checker to.
"""
print('Hello world')
We can run this plugin by placing this module in the PYTHONPATH and invoking
**pylint** as:
.. sourcecode:: bash
$ pylint -E --load-plugins hello_plugin foo.py
Hello world
We can extend hello-world plugin to ignore some specific names using
``load_configuration`` function:
.. sourcecode:: python
# Inside hello_plugin.py
from typing import TYPE_CHECKING
import astroid
if TYPE_CHECKING:
from pylint.lint import PyLinter
def register(linter: "PyLinter") -> None:
"""This required method auto registers the checker during initialization.
:param linter: The linter to register the checker to.
"""
print('Hello world')
def load_configuration(linter):
name_checker = get_checker(linter, NameChecker)
# We consider as good names of variables Hello and World
name_checker.config.good_names += ('Hello', 'World')
# We ignore bin directory
linter.config.black_list += ('bin',)
Depending if we need a **transform plugin** or a **checker**, this might not
be enough. For the former, this is enough to declare the module as a plugin,
but in the case of the latter, we need to register our checker with the linter
object, by calling the following inside the ``register`` function::
linter.register_checker(OurChecker(linter))
For more information on writing a checker see :ref:`write_a_checker`.
|
