changelog

name	changelog
description	Generate and manage changelogs from git history. Use for release notes, tracking breaking changes, and maintaining project history.

Changelog Generator

Generate changelogs from git commits and manage release notes.

Prerequisites

# Git
git --version

# GitHub CLI (for release notes)
brew install gh
gh auth login

# Gemini (for AI summaries)
pip install google-generativeai
export GEMINI_API_KEY=your_api_key

CLI Reference

Git History Commands

# Recent commits
git log --oneline -20

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

# Between tags
git log v1.0.0..v1.1.0 --oneline

# With full messages
git log v1.0.0..v1.1.0 --pretty=format:"%h %s%n%b"

# By author
git log --author="name" --oneline -10

# With dates
git log --format="%h %ad %s" --date=short

Finding Tags

# List all tags
git tag

# List tags with dates
git tag --sort=-creatordate --format='%(refname:short) %(creatordate:short)'

# Latest tag
git describe --tags --abbrev=0

# Tags matching pattern
git tag -l "v1.*"

Generating Changelogs

From Git Log

# Simple changelog since tag
git log v1.0.0..HEAD --oneline > CHANGELOG_DRAFT.md

# Categorized by conventional commits
git log v1.0.0..HEAD --oneline | grep "^[a-f0-9]* feat:"
git log v1.0.0..HEAD --oneline | grep "^[a-f0-9]* fix:"
git log v1.0.0..HEAD --oneline | grep "^[a-f0-9]* chore:"

Using GitHub CLI

# Generate release notes
gh release create v1.1.0 --generate-notes

# View release notes draft
gh release create v1.1.0 --generate-notes --notes-start-tag v1.0.0 --dry-run

# From existing release
gh release view v1.0.0

AI-Generated Changelog

# Get commits since last tag
COMMITS=$(git log $(git describe --tags --abbrev=0)..HEAD --pretty=format:"%s%n%b")

# Generate polished changelog
gemini -m pro -o text -e "" "Generate a changelog from these commits:

$COMMITS

Format as:
## [Version] - Date

### Added
- New features

### Changed
- Modifications

### Fixed
- Bug fixes

### Breaking Changes
- Any breaking changes

Write user-friendly descriptions, not raw commit messages."

Workflow Patterns

Release Preparation

#!/bin/bash
VERSION=$1
LAST_TAG=$(git describe --tags --abbrev=0)

echo "# Release $VERSION"
echo ""
echo "Changes since $LAST_TAG:"
echo ""

# Categorize commits
echo "## Features"
git log $LAST_TAG..HEAD --oneline | grep -i "feat:" | sed 's/^[a-f0-9]* feat: /- /'

echo ""
echo "## Fixes"
git log $LAST_TAG..HEAD --oneline | grep -i "fix:" | sed 's/^[a-f0-9]* fix: /- /'

echo ""
echo "## Other"
git log $LAST_TAG..HEAD --oneline | grep -v -i "feat:\|fix:" | sed 's/^[a-f0-9]* /- /'

Breaking Changes Detection

# Find breaking changes in commit messages
git log v1.0.0..HEAD --oneline | grep -i "breaking\|BREAKING"

# Find in commit bodies
git log v1.0.0..HEAD --grep="BREAKING" --pretty=format:"%h %s"

Maintaining CHANGELOG.md

Standard format (Keep a Changelog):

# Changelog

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

## [Unreleased]

### Added
- New feature X

### Changed
- Updated Y

### Fixed
- Bug in Z

## [1.1.0] - 2024-01-15

### Added
- Feature A
- Feature B

### Fixed
- Issue #123

Update Script

#!/bin/bash
VERSION=$1
DATE=$(date +%Y-%m-%d)

# Generate new section
NEW_SECTION="## [$VERSION] - $DATE

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

# Prepend to changelog (after header)
head -7 CHANGELOG.md > CHANGELOG_NEW.md
echo "" >> CHANGELOG_NEW.md
echo "$NEW_SECTION" >> CHANGELOG_NEW.md
echo "" >> CHANGELOG_NEW.md
tail -n +8 CHANGELOG.md >> CHANGELOG_NEW.md
mv CHANGELOG_NEW.md CHANGELOG.md

Statistics

# Commits by author since tag
git shortlog -sn v1.0.0..HEAD

# Files changed
git diff --stat v1.0.0..HEAD | tail -1

# Commits per day
git log --format="%ad" --date=short v1.0.0..HEAD | sort | uniq -c

# Most changed files
git diff --stat v1.0.0..HEAD | sort -k3 -n -r | head -10

GitHub Releases

# Create release with notes
gh release create v1.1.0 --title "v1.1.0" --notes-file RELEASE_NOTES.md

# Create from tag with auto-notes
gh release create v1.1.0 --generate-notes

# Edit existing release
gh release edit v1.1.0 --notes-file UPDATED_NOTES.md

# List releases
gh release list

# Download release assets
gh release download v1.1.0

Best Practices

1. Use conventional commits - Enables automatic categorization
2. Tag releases - Clean boundaries for changelogs
3. Write for users - Translate technical to user impact
4. Note breaking changes - Prominently marked
5. Include issue references - Link to related issues
6. Date your releases - Clear timeline
7. Keep unreleased section - Track ongoing work