ruff

Ruff is an extremely fast Python linter and formatter, written in Rust. It aims to be a single, high-performance tool that can replace a multitude of existing Python code quality tools such as Flake8, Black, isort, Pylint, pydocstyle, and more. Its primary goal is to provide a comprehensive, configurable, and incredibly fast solution for enforcing code style and detecting common programming errors in Python projects.

Key features of ruff include:
- Blazing Fast Performance: Due to its implementation in Rust, ruff is significantly faster than most traditional Python-based linters and formatters, making it ideal for large codebases and continuous integration pipelines.
- Comprehensive Rule Set: Ruff incorporates and implements rules from various linters, allowing users to enable or disable specific rule categories (e.g., Flake8's `E` and `W` rules, Pylint, isort, etc.) through a unified configuration. This consolidates many tools into one.
- Automatic Fixes: Many of ruff's diagnostic rules come with an automatic fix capability, allowing it to reformat code, remove unused imports, fix indentation issues, and address other style violations with a single command.
- Extensive Configuration: Ruff is highly configurable via `pyproject.toml`, `ruff.toml`, or `.ruff.toml` files, enabling users to specify rules to include/exclude, ignore paths, target Python versions, and define custom formatting options.
- Integration: It integrates seamlessly with popular development environments (like VS Code through extensions), pre-commit hooks, and CI/CD pipelines, making it easy to incorporate into existing workflows.

By using ruff, developers can ensure code consistency, improve readability, catch potential bugs early in the development cycle, and enforce project-specific coding standards efficiently. It simplifies the setup and maintenance of code quality tools by consolidating their functionality into a single, high-performance binary.

 1. Installation
pip install ruff

 2. Example Python file (main.py) with some common issues

 main.py
import os
import sys

def calculate_sum (a, b):
     This is a comment that's too long and not formatted properly. It needs to be shorter.
    result = a + b
    if result > 0: print("Positive sum")  Bad inline statement
    return result

class MyClass:
    def __init__ (self, value):
        self.value = value
        self.unused_variable = 10  Unused variable

    def get_value (self):
        return self.value

def main ():
    x = 5
    y = 10
    total = calculate_sum(x,y)
    print(f"The total is: {total}")

if __name__ == "__main__":
    main()

 3. How to run ruff to check for issues (from your terminal in the same directory as main.py)
 ruff check main.py

 4. How to run ruff to automatically fix issues
 ruff check main.py --fix

 5. Example pyproject.toml configuration for more control (create this file in your project root)

 pyproject.toml
[tool.ruff]
line-length = 88
target-version = "py310"
select = ["E", "W", "F", "I", "N", "D", "UP", "B", "A", "C90"]  Select common rule sets
ignore = ["D100", "D104", "E501"]  Ignore specific rules (e.g., missing docstrings for modules/packages, line too long)

[tool.ruff.mccabe]  Configuration for complexity rules
max-complexity = 10

[tool.ruff.isort]  Configuration for import sorting
known-first-party = ["my_project"]  Treat 'my_project' as a first-party import
force-single-line = false