Pylint

Pylint is a comprehensive static code analysis tool for Python that analyzes source code without executing it, identifying programming errors, enforcing coding standards (PEP 8), checking for code smells, and providing metrics about code complexity and maintainability. Created in 2003 by Sylvain Thenault and Logilab, Pylint is one of the oldest and most thorough Python linters, with over 5,000 GitHub stars and millions of weekly downloads via pip. The tool performs deep analysis including undefined variable detection, unreachable code identification, import checking (unused imports, wrong import position), type checking using type hints and inference, naming convention validation configurable to match any style guide, line length and formatting checks, duplicate code detection, code complexity metrics (cyclomatic complexity, maintainability index, number of statements, methods, and attributes per class), design recommendations about refactoring opportunities, and comparison against module interfaces to catch signature mismatches. Pylint checks are organized into categories: Error (E), Warning (W), Convention (C), Refactor (R), and Fatal (F), each with configurable enable/disable rules. The tool supports incremental analysis for faster repeated runs, parallel execution across multiple CPU cores, custom checkers via plugin API, .pylintrc or pyproject.toml configuration files, and generates reports with global evaluation scores (rated out of 10). Pylint integrates with most Python IDEs including VS Code, PyCharm, Vim, and Emacs, and can be used as a pre-commit hook or CI/CD pipeline step. The current version is 3.3.x, released under the GPLv2 license.