changelog-generator

name: changelog-generator description: Transform git commits into customer-friendly release notes and changelogs. Use when preparing releases, generating CHANGELOG.md, or creating release documentation.

Changelog Generator

When to Use This Skill

• Preparing a new release
• Generating CHANGELOG.md updates
• Creating release notes for customers
• Summarizing changes between versions
• Automating release documentation

Changelog Format (Keep a Changelog)

Follow the Keep a Changelog format:

# 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/1.1.0/),
and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).

## [Unreleased]

### Added
- New feature X for doing Y

### Changed
- Updated dependency Z to version 2.0

### Deprecated
- Feature A will be removed in version 3.0

### Removed
- Dropped support for Node.js 14

### Fixed
- Resolved issue where X caused Y (#123)

### Security
- Updated library X to patch CVE-2024-XXXX

## [1.2.0] - 2024-01-15

### Added
- Dark mode support
- Export to PDF feature

### Fixed
- Memory leak in data processing (#456)

[Unreleased]: https://github.com/user/repo/compare/v1.2.0...HEAD
[1.2.0]: https://github.com/user/repo/compare/v1.1.0...v1.2.0

Commit Convention (Conventional Commits)

<type>(<scope>): <description>

[optional body]

[optional footer(s)]

Types

Breaking Changes

feat(api)!: change authentication method

BREAKING CHANGE: API now requires OAuth2 instead of API keys.
Migration guide at https://docs.example.com/migration

Git Commands for Changelog

Get Commits Since Last Tag

# List commits since last tag
git log $(git describe --tags --abbrev=0)..HEAD --oneline

# With conventional commit format
git log $(git describe --tags --abbrev=0)..HEAD --pretty=format:"%s"

# Group by type
git log $(git describe --tags --abbrev=0)..HEAD --pretty=format:"%s" | \
  grep -E "^(feat|fix|docs|style|refactor|perf|test|build|ci|chore)(\(.+\))?:" | \
  sort

Get Commits Between Tags

# Between specific versions
git log v1.0.0..v1.1.0 --oneline

# With author and date
git log v1.0.0..v1.1.0 --pretty=format:"%h - %s (%an, %ar)"

Extract PR Numbers

# Find PR references in commits
git log v1.0.0..HEAD --oneline | grep -oE "#[0-9]+" | sort -u

Automation Script

#!/bin/bash
# generate-changelog.sh

VERSION=$1
PREVIOUS_TAG=$(git describe --tags --abbrev=0 2>/dev/null || echo "")

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

# Added (feat)
ADDED=$(git log ${PREVIOUS_TAG:+$PREVIOUS_TAG..}HEAD --pretty=format:"%s" | grep "^feat" | sed 's/^feat(\([^)]*\)): /- **\1**: /' | sed 's/^feat: /- /')
if [ -n "$ADDED" ]; then
  echo "### Added"
  echo "$ADDED"
  echo ""
fi

# Fixed (fix)
FIXED=$(git log ${PREVIOUS_TAG:+$PREVIOUS_TAG..}HEAD --pretty=format:"%s" | grep "^fix" | sed 's/^fix(\([^)]*\)): /- **\1**: /' | sed 's/^fix: /- /')
if [ -n "$FIXED" ]; then
  echo "### Fixed"
  echo "$FIXED"
  echo ""
fi

# Changed (refactor, perf)
CHANGED=$(git log ${PREVIOUS_TAG:+$PREVIOUS_TAG..}HEAD --pretty=format:"%s" | grep -E "^(refactor|perf)" | sed 's/^\(refactor\|perf\)(\([^)]*\)): /- **\2**: /' | sed 's/^\(refactor\|perf\): /- /')
if [ -n "$CHANGED" ]; then
  echo "### Changed"
  echo "$CHANGED"
  echo ""
fi

# Security
SECURITY=$(git log ${PREVIOUS_TAG:+$PREVIOUS_TAG..}HEAD --pretty=format:"%s" | grep -i "security\|CVE\|vulnerability")
if [ -n "$SECURITY" ]; then
  echo "### Security"
  echo "$SECURITY" | sed 's/^/- /'
  echo ""
fi

Customer-Friendly Release Notes

Transform technical commits into user-facing notes:

Technical Commit

fix(auth): resolve race condition in token refresh causing intermittent 401 errors

Customer-Friendly

### Fixed
- Resolved an issue where some users were unexpectedly logged out during long sessions

Transformation Guidelines

GitHub Release Notes

# Generate release notes from GitHub
gh release create v1.2.0 --generate-notes

# Create with custom notes
gh release create v1.2.0 --notes-file RELEASE_NOTES.md

# View existing release notes
gh release view v1.2.0

Semantic Versioning

MAJOR.MINOR.PATCH

MAJOR: Breaking changes
MINOR: New features (backward compatible)
PATCH: Bug fixes (backward compatible)

When to Bump

Checklist

• Collect all commits since last release
• Categorize by type (Added, Changed, Fixed, etc.)
• Rewrite technical details for end users
• Include issue/PR references
• Note breaking changes prominently
• Update version links at bottom
• Review for sensitive information
• Proofread for clarity