changelog-generator

What this skill does

# Changelog Generator Skill

Automatically generate changelogs from git commits following conventional commits, semantic versioning, and best practices.

## Instructions

You are a changelog generation expert. When invoked:

1. **Analyze Commit History**:
   - Parse git commit messages
   - Identify conventional commit types
   - Group related changes
   - Determine version bumps (major, minor, patch)

2. **Generate Changelog Entries**:
   - Follow Keep a Changelog format
   - Categorize by change type
   - Include breaking changes prominently
   - Add relevant metadata (dates, versions, authors)

3. **Format Output**:
   - Use markdown formatting
   - Create clear section headers
   - Add links to commits and PRs
   - Include migration guides for breaking changes

4. **Version Management**:
   - Suggest semantic version numbers
   - Identify breaking changes
   - Track deprecations
   - Handle pre-release versions

## Conventional Commit Types

- **feat**: New feature (minor version bump)
- **fix**: Bug fix (patch version bump)
- **docs**: Documentation changes
- **style**: Code style changes (formatting, etc.)
- **refactor**: Code refactoring
- **perf**: Performance improvements
- **test**: Test additions or changes
- **build**: Build system changes
- **ci**: CI/CD changes
- **chore**: Maintenance tasks
- **revert**: Revert previous changes

**Breaking Change**: Any commit with `BREAKING CHANGE:` in body or `!` after type (major version bump)

## Usage Examples

```
@changelog-generator
@changelog-generator --since v1.2.0
@changelog-generator --unreleased
@changelog-generator --version 2.0.0
@changelog-generator --format keep-a-changelog
@changelog-generator --include-authors
```

## Changelog Formats

### Keep a Changelog Format

```markdown
# Changelog

All notable changes to this project will be documented in this file.

The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).

## [Unreleased]

### Added
- New feature X for improved user experience
- Support for configuration option Y

### Changed
- Updated dependency Z to version 2.0
- Improved performance of data processing

### Deprecated
- Function `oldMethod()` - use `newMethod()` instead

### Removed
- Removed deprecated API endpoint `/api/v1/old`

### Fixed
- Fixed memory leak in cache implementation
- Corrected timezone handling in date formatter

### Security
- Fixed XSS vulnerability in user input handling
- Updated crypto library to address CVE-2024-1234

## [1.5.0] - 2024-01-15

### Added
- User authentication with OAuth2
- Export functionality for reports
- Dark mode theme support

### Changed
- Redesigned dashboard UI
- Optimized database queries

### Fixed
- Fixed bug in pagination logic
- Resolved CORS issues with API

## [1.4.2] - 2024-01-10

### Fixed
- Critical bug in payment processing
- Memory leak in WebSocket connections

### Security
- Patched authentication bypass vulnerability

## [1.4.1] - 2024-01-05

### Fixed
- Hotfix for broken deployment script
- Fixed typo in error messages

## [1.4.0] - 2024-01-01

### Added
- Real-time notifications
- File upload with drag and drop
- Advanced search filters

### Changed
- Migrated from REST to GraphQL
- Updated UI components library

### Deprecated
- Old REST API endpoints (will be removed in 2.0)

[Unreleased]: https://github.com/user/repo/compare/v1.5.0...HEAD
[1.5.0]: https://github.com/user/repo/compare/v1.4.2...v1.5.0
[1.4.2]: https://github.com/user/repo/compare/v1.4.1...v1.4.2
[1.4.1]: https://github.com/user/repo/compare/v1.4.0...v1.4.1
[1.4.0]: https://github.com/user/repo/releases/tag/v1.4.0
```

## Automated Changelog Generation

### Using Git Commits

```bash
#!/bin/bash
# generate-changelog.sh - Generate changelog from git commits

VERSION=${1:-"Unreleased"}
PREV_TAG=$(git describe --tags --abbrev=0 2>/dev/null || echo "")

echo "# Changelog"
echo ""
echo "## [$VERSION] - $(date +%Y-%m-%d)"
echo ""

# Get commits since last tag
if [ -z "$PREV_TAG" ]; then
  COMMITS=$(git log --pretty=format:"%s|||%h|||%an" --reverse)
else
  COMMITS=$(git log ${PREV_TAG}..HEAD --pretty=format:"%s|||%h|||%an" --reverse)
fi

# Arrays for different categories
declare -a features=()
declare -a fixes=()
declare -a breaking=()
declare -a docs=()
declare -a chores=()
declare -a other=()

# Parse commits
while IFS='|||' read -r message hash author; do
  case "$message" in
    feat:*|feat\(*\):*)
      features+=("- ${message#feat*: } ([${hash}](../../commit/${hash}))")
      ;;
    fix:*|fix\(*\):*)
      fixes+=("- ${message#fix*: } ([${hash}](../../commit/${hash}))")
      ;;
    *BREAKING*|*\!:*)
      breaking+=("- ${message} ([${hash}](../../commit/${hash}))")
      ;;
    docs:*)
      docs+=("- ${message#docs: } ([${hash}](../../commit/${hash}))")
      ;;
    chore:*|build:*|ci:*)
      chores+=("- ${message#*: } ([${hash}](../../commit/${hash}))")
      ;;
    *)
      other+=("- ${message} ([${hash}](../../commit/${hash}))")
      ;;
  esac
done <<< "$COMMITS"

# Output sections
if [ ${#breaking[@]} -gt 0 ]; then
  echo "### ⚠️ BREAKING CHANGES"
  echo ""
  printf '%s\n' "${breaking[@]}"
  echo ""
fi

if [ ${#features[@]} -gt 0 ]; then
  echo "### Added"
  echo ""
  printf '%s\n' "${features[@]}"
  echo ""
fi

if [ ${#fixes[@]} -gt 0 ]; then
  echo "### Fixed"
  echo ""
  printf '%s\n' "${fixes[@]}"
  echo ""
fi

if [ ${#docs[@]} -gt 0 ]; then
  echo "### Documentation"
  echo ""
  printf '%s\n' "${docs[@]}"
  echo ""
fi

if [ ${#chores[@]} -gt 0 ]; then
  echo "### Internal"
  echo ""
  printf '%s\n' "${chores[@]}"
  echo ""
fi

if [ ${#other[@]} -gt 0 ]; then
  echo "### Other Changes"
  echo ""
  printf '%s\n' "${other[@]}"
  echo ""
fi
```

### Using conventional-changelog

```bash
# Install
npm install -g conventional-changelog-cli

# Generate changelog
conventional-changelog -p angular -i CHANGELOG.md -s

# For first release
conventional-changelog -p angular -i CHANGELOG.md -s -r 0

# With specific version
conventional-changelog -p angular -i CHANGELOG.md -s --release-count 0 \
  --tag-prefix v --preset angular
```

**package.json configuration:**
```json
{
  "scripts": {
    "changelog": "conventional-changelog -p angular -i CHANGELOG.md -s",
    "version": "npm run changelog && git add CHANGELOG.md"
  },
  "devDependencies": {
    "conventional-changelog-cli": "^4.1.0"
  }
}
```

### Using standard-version

```bash
# Install
npm install -D standard-version

# Generate changelog and bump version
npx standard-version

# Preview without committing
npx standard-version --dry-run

# First release
npx standard-version --first-release

# Specific version
npx standard-version --release-as minor
npx standard-version --release-as 1.1.0

# Pre-release
npx standard-version --prerelease alpha
```

**package.json:**
```json
{
  "scripts": {
    "release": "standard-version",
    "release:minor": "standard-version --release-as minor",
    "release:major": "standard-version --release-as major",
    "release:alpha": "standard-version --prerelease alpha"
  },
  "standard-version": {
    "types": [
      {"type": "feat", "section": "Features"},
      {"type": "fix", "section": "Bug Fixes"},
      {"type": "chore", "hidden": true},
      {"type": "docs", "section": "Documentation"},
      {"type": "style", "hidden": true},
      {"type": "refactor", "section": "Code Refactoring"},
      {"type": "perf", "section": "Performance Improvements"},
      {"type": "test", "hidden": true}
    ]
  }
}
```

### Using release-please (GitHub Action)

**.github/workflows/release.yml:**
```yaml
name: Release

on:
  push:
    branches:
      - main

jobs:
  release:
    runs-on: ubuntu-latest
    steps:
      - uses: google-github-actions/release-please-action@v3
        id: release
        with:
          release-type: node
          package-name: my-package

      - uses: actions/checkout@v3
        if: ${{ steps.release.outputs.release_create