pylint

PyLint is a static code analysis tool for Python. It analyzes Python source code to identify programming errors, enforce coding standards, and flag code smells and potential issues before runtime.

It checks a wide range of conditions, including undefined or unused variables, redefined or missing names, syntax errors, and improper imports. PyLint also checks conformance to common style and naming conventions and can assess code complexity through the McCabe metric when the related extension is enabled. Message codes categorize findings into convention (C), refactor (R), warning (W), error (E), and fatal (F).

Results are reported in a configurable format, typically as text with line numbers and message IDs, and can be exported as JSON or HTML. PyLint provides a score from 0 to 10 that summarizes overall code quality for a given run. It can be integrated into editors, IDEs, and continuous integration pipelines, and can be invoked from the command line or as part of a build script.

Configuration is flexible through a project-wide configuration file (.pylintrc or pylint.rc) and per-run command-line options. Users can enable or disable specific checks, define ignored modules, and extend PyLint with plugins. The project supports a large ecosystem of extensions that add new checkers or integrate with other tools.

PyLint is maintained by the Python community and has become one of the most widely used linters for Python code. It is complementary to style checkers like flake8 and tools that enforce formatting, such as Black, and is commonly used in code review and CI environments.