Code Quality

# Check for issues
ruff check .

# Check and automatically fix issues
ruff check --fix .

# Format code
ruff format .

# Check only changed files
prek run ruff-check

[tool.ruff]
required-version = ">=0.15.1"

[tool.ruff.lint]
select = [
  "E",      # pycodestyle errors
  "F",      # pyflakes/autoflake
  "W",      # pycodestyle warnings
  "I",      # isort (import sorting)
  "UP",     # pyupgrade (modern Python syntax)
  "ASYNC",  # flake8-async
  "B",      # flake8-bugbear
  "SIM",    # flake8-simplify
  "PL",     # pylint
  "RUF",    # ruff-specific rules
  # ... and many more
]

# Lint a specific file
pylint homeassistant/components/light/init.py

# Lint changed files
script/lint

# Lint via pre-commit
prek run pylint

[tool.pylint.MAIN]
py-version = "3.14"
jobs = 2
load-plugins = [
  "pylint.extensions.code_style",
  "pylint.extensions.typing",
  "hass_async_load_fixtures",
  "hass_decorator",
  # ... custom plugins
]

# Check all files
mypy homeassistant/

# Check specific file
mypy homeassistant/components/light/__init__.py

# Via pre-commit
prek run mypy

from homeassistant.core import HomeAssistant
from homeassistant.config_entries import ConfigEntry

async def async_setup_entry(
    hass: HomeAssistant,
    entry: ConfigEntry,
) -> bool:
    """Set up from a config entry."""
    return True

# Check spelling
codespell

# Via pre-commit
prek run codespell

- id: codespell
  args:
    - --ignore-words-list=aiport,astroid,checkin,currenty,hass,iif,incomfort,lookin,nam,NotIn
    - --skip="./.*,*.csv,*.json,*.ambr"
    - --quiet-level=2

# Run hassfest checks
python3 -m script.hassfest

# Via pre-commit
prek run hassfest

prek install

repos:
  - repo: https://github.com/astral-sh/ruff-pre-commit
    hooks:
      - id: ruff-check
        args: [--fix]
      - id: ruff-format

  - repo: https://github.com/codespell-project/codespell
    hooks:
      - id: codespell

  - repo: local
    hooks:
      - id: mypy
        entry: script/run-in-env.sh mypy
      - id: pylint
        entry: script/run-in-env.sh pylint --ignore-missing-annotations=y
      - id: hassfest
        entry: script/run-in-env.sh python3 -m script.hassfest

# Run all hooks on all files
prek run --all-files

# Run specific hook
prek run ruff-check --all-files

# Run hooks on specific files
prek run --files path/to/file.py

"""Module docstring."""
# Standard library imports
import asyncio
import logging
from typing import Any

# Third-party imports
import voluptuous as vol

# Home Assistant imports
from homeassistant.core import HomeAssistant
from homeassistant.helpers import config_validation as cv

[tool.ruff.lint.isort]
force-sort-within-sections = true
known-first-party = ["homeassistant"]
combine-as-imports = true

def my_function(param1: str, param2: int) -> bool:
    """Brief description of function.

    Longer description if needed.

    Args:
        param1: Description of param1.
        param2: Description of param2.

    Returns:
        Description of return value.

    Raises:
        ValueError: When parameter is invalid.
    """
    return True

[tool.ruff.lint.pydocstyle]
convention = "google"

async def async_setup_entry(hass: HomeAssistant, entry: ConfigEntry) -> bool:
    """Set up from config entry."""
    await async_initialize()
    return True

ruff check --select I --fix path/to/file.py

# Before
def my_function(hass, config):
    pass

# After
def my_function(hass: HomeAssistant, config: dict[str, Any]) -> None:
    pass

# Before: Too many arguments
def setup(hass, config, arg1, arg2, arg3, arg4, arg5, arg6):
    pass

# After: Use a config object or dataclass
from dataclasses import dataclass

@dataclass
class SetupConfig:
    arg1: str
    arg2: int
    # ...

def setup(hass: HomeAssistant, config: SetupConfig) -> None:
    pass

# Break complex functions into smaller ones
def complex_function():
    result = _step_one()
    result = _step_two(result)
    return _step_three(result)

def _step_one():
    pass

def _step_two(data):
    pass

def _step_three(data):
    pass

{
  "domain": "example",
  "quality_scale": "gold"
}