PRE_COMMIT.md

Pre-commit Hooks Setup Guide

Overview

Pre-commit hooks automatically check your code before commits, ensuring code quality and preventing common issues. This guide helps you set up hooks based on your project's requirements.

Quick Start

1. Install Pre-commit

   uv add --dev pre-commit

2. Create Configuration Create .pre-commit-config.yaml with your chosen hooks

3. Install Hooks

   pre-commit install
   pre-commit install --hook-type pre-push  # For pre-push hooks

Choosing Hooks for Your Project

Essential Hooks (Recommended for all projects)

• Ruff: Fast Python linting and formatting
  • Template: pre-commit-ruff-hook.yaml
  • Purpose: Maintain code quality
• Type checking: MyPy or Pyright
  • Template: pre-commit-mypy-hook.yaml
  • Purpose: Catch type errors early

Additional Quality Hooks

• Secret detection: Prevent credential leaks
  • Template: pre-commit-secrets-hook.yaml
• Test coverage: Ensure adequate testing
  • Template: pre-commit-coverage-hook.yaml
• Documentation: Markdown and YAML validation
  • Template: pre-commit-markdown-hook.yaml

Available Hook Templates

Code Quality

• Ruff: pre-commit-ruff-hook.yaml
• Black: pre-commit-black-hook.yaml
• isort: pre-commit-isort-hook.yaml

Type Checking

• MyPy: pre-commit-mypy-hook.yaml
• Pyright: pre-commit-pyright-hook.yaml

Testing

• Coverage: pre-commit-coverage-hook.yaml
• Pytest: pre-commit-pytest-hook.yaml

Security

• Secrets: pre-commit-secrets-hook.yaml
• Bandit: pre-commit-bandit-hook.yaml
• Safety: pre-commit-safety-hook.yaml

Documentation

• Markdown: pre-commit-markdown-hook.yaml
• YAML: pre-commit-yaml-hook.yaml

Setting Up Hooks

Step 1: Start with a Basic Configuration

Create .pre-commit-config.yaml with essential hooks:

repos:
  # Ruff - Fast Python linter and formatter
  - repo: https://github.com/astral-sh/ruff-pre-commit
    rev: v0.8.0
    hooks:
      - id: ruff
        args: [--fix, --exit-non-zero-on-fix]
      - id: ruff-format

  # Standard hooks
  - repo: https://github.com/pre-commit/pre-commit-hooks
    rev: v4.5.0
    hooks:
      - id: trailing-whitespace
      - id: end-of-file-fixer
      - id: check-yaml
      - id: check-added-large-files

Step 2: Add Additional Hooks

Copy configurations from templates/cicd/hooks/ for:

• Type checking (mypy)
• Secret detection
• Test coverage
• Other project-specific needs

Step 3: Configure Hook Stages

# Default stage (pre-commit)
- id: ruff-check
  stages: [commit]

# Pre-push stage
- id: test-coverage
  stages: [push]

# Manual stage
- id: full-test-suite
  stages: [manual]

Step 4: Install and Test

# Install hooks
pre-commit install
pre-commit install --hook-type pre-push

# Test all hooks
pre-commit run --all-files

# Test specific hook
pre-commit run ruff-check --all-files

# Run manual stage hooks
pre-commit run --hook-stage manual

Hook Stages

Pre-commit Stage

Runs before each commit:

• Fast checks (< 5 seconds)
• Formatting fixes
• Basic linting

Pre-push Stage

Runs before pushing:

• Type checking
• Test coverage
• Security scans

Manual Stage

Run on demand:

• Full test suite
• Performance benchmarks
• Deep security analysis

Using uv with Pre-commit

Configure hooks to use uv:

- repo: local
  hooks:
    - id: pytest
      name: Run tests
      entry: uv run pytest
      language: system
      pass_filenames: false

Common Hook Patterns

Auto-fixing Hooks

- id: ruff-format
  name: Format with ruff
  entry: uv run ruff format
  language: system
  types: [python]
  # Files are automatically staged after fixes

Conditional Hooks

- id: test-changed
  name: Test changed files
  entry: uv run pytest
  language: system
  files: \.py$
  pass_filenames: true

Exclude Patterns

- id: mypy
  name: Type check
  entry: uv run mypy
  language: system
  types: [python]
  exclude: ^(tests/|docs/|examples/)

Best Practices

1. Start Small

Begin with essential hooks and add more gradually:

• Format checking
• Basic linting
• Secret detection

2. Keep Hooks Fast

Pre-commit hooks should complete quickly:

• Use --hook-stage for slow checks
• Run comprehensive tests in CI/CD
• Cache results when possible

3. Auto-fix When Possible

Enable auto-fixing for formatting:

- id: ruff-format
  args: [--fix]

4. Document Hook Configuration

In your README or contributing guide, document:

• Which hooks are required for contributors
• How to run hooks manually
• How to temporarily skip hooks (emergency only)

Troubleshooting

Common Issues

Hook Installation Failed

# Clear and reinstall
pre-commit clean
pre-commit uninstall
pre-commit install

Hook Timeout

# Increase timeout for slow hooks
- id: slow-hook
  timeout: 300  # 5 minutes

File Not Found

# Ensure dependencies are installed
uv sync --dev

Skipping Hooks (Emergency)

# Skip hooks for emergency commit
git commit --no-verify -m "Emergency fix"

# Skip specific hook
SKIP=hook-id git commit -m "Message"

CI/CD Integration

Validate Hooks in CI

# GitHub Actions example
- name: Run pre-commit
  run: |
    uv add --dev pre-commit
    pre-commit run --all-files

Pre-commit CI Service

# .pre-commit-config.yaml
ci:
  autofix_commit_msg: 'Auto-fix from pre-commit.ci'
  autofix_prs: true
  autoupdate_schedule: weekly

Related Documentation

• Pre-commit Documentation
• GitHub Actions Setup
• Package Management
• Test Coverage

Template Information

• Source: vibe-coding-templates
• Version: 1.0.0
• Date: 2025-08-19
• Author: chrishayuk
• Template: Generic Python Project

Customization Notes

When using this guide:

1. Start with essential hooks (ruff, basic checks)
2. Add more hooks gradually based on team needs
3. Test hooks locally before committing config
4. Document any hook overrides or exceptions
5. Keep hooks fast to maintain developer productivity