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)

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/1.1.0/),
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)

code

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

[optional body]

[optional footer(s)]

Types

Type	Description	Changelog Section
`feat`	New feature	Added
`fix`	Bug fix	Fixed
`docs`	Documentation	(usually skip)
`style`	Formatting	(usually skip)
`refactor`	Code restructure	Changed
`perf`	Performance	Changed
`test`	Tests	(usually skip)
`build`	Build system	(usually skip)
`ci`	CI/CD	(usually skip)
`chore`	Maintenance	(usually skip)
`revert`	Revert commit	Removed
`security`	Security fix	Security
`deprecate`	Deprecation	Deprecated

Breaking Changes

code

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

bash

# 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

bash

# 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

bash

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

Automation Script

bash

#!/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

code

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

Customer-Friendly

code

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

Transformation Guidelines

Technical	Customer-Friendly
"refactor X"	"Improved performance of X"
"fix race condition"	"Resolved intermittent issues with..."
"add validation"	"Enhanced security of..."
"update dependency"	"Improved stability"
"fix memory leak"	"Improved application performance"

GitHub Release Notes

bash

# 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

code

MAJOR.MINOR.PATCH

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

When to Bump

Change Type	Version Bump
Breaking API change	MAJOR
New feature	MINOR
Bug fix	PATCH
Security fix	PATCH (or MINOR if adds feature)
Performance improvement	PATCH
Deprecation notice	MINOR

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