Changelog Generator

Generate structured changelogs from git commit history using conventional commits.

Usage

code

/changelog                          # since last tag
/changelog v1.2.0..v1.3.0          # between tags
/changelog --since="2 weeks ago"    # date range
/changelog main..feature-branch     # branch diff

Workflow

Step 1: Determine Range

Parse user input to determine the git range:

bash

# Default: last tag to HEAD
LAST_TAG=$(git describe --tags --abbrev=0 2>/dev/null || echo "")
if [ -n "$LAST_TAG" ]; then
  RANGE="$LAST_TAG..HEAD"
else
  RANGE="HEAD~50..HEAD"  # fallback: last 50 commits
fi

# User-specified range
RANGE="v1.2.0..v1.3.0"

# Date-based
git log --after="2025-01-01" --before="2025-02-01" --oneline

Step 2: Extract Commits

bash

# Get conventional commit log with authors
git log $RANGE --pretty=format:"%h|%s|%an|%ad" --date=short

# Include PR numbers if available
git log $RANGE --pretty=format:"%h|%s|%an" --grep="(#[0-9]*)"

Step 3: Categorize

Group commits by conventional commit prefix:

Prefix	Category	Emoji
`feat:`	Features	n/a
`fix:`	Bug Fixes	n/a
`perf:`	Performance	n/a
`refactor:`	Refactoring	n/a
`docs:`	Documentation	n/a
`test:`	Tests	n/a
`ci:`	CI/CD	n/a
`chore:`	Maintenance	n/a
`BREAKING CHANGE`	Breaking Changes	n/a

Commits without conventional prefix: categorize by analyzing the message.

Step 4: Enrich

For each commit, optionally:

•Link PR numbers: #123 -> [#123](https://github.com/org/repo/pull/123)
•Link issues: fixes #456 -> [#456](https://github.com/org/repo/issues/456)
•Get PR title if commit message is a merge commit
•Attribute contributors

Detect repo origin for links:

bash

REMOTE_URL=$(git remote get-url origin 2>/dev/null)

Step 5: Generate Output

Default format: Markdown

markdown

# Changelog

## [v1.3.0] - 2025-02-05

### Breaking Changes
- Description of breaking change (#PR)

### Features
- Add user authentication flow (#123) - @author
- Support batch processing for imports (#124) - @author

### Bug Fixes
- Fix race condition in session handler (#125) - @author

### Performance
- Optimize database query for user lookup (#126) - @author

### Contributors
@author1, @author2, @author3

Options

Flag	Effect
`--format=md`	Markdown (default)
`--format=json`	JSON output
`--format=slack`	Slack-friendly format
`--no-links`	Skip PR/issue linking
`--no-authors`	Omit contributor attribution
`--breaking-only`	Only show breaking changes
`--include-merge`	Include merge commits (excluded by default)

Slack Format

When --format=slack or user asks for Slack-friendly output:

code

*Release v1.3.0* (2025-02-05)

*Breaking Changes*
- Description of breaking change (<link|#PR>)

*Features*
- Add user authentication flow (<link|#123>)

*Bug Fixes*
- Fix race condition in session handler (<link|#125>)

JSON Format

json

{
  "version": "v1.3.0",
  "date": "2025-02-05",
  "range": "v1.2.0..v1.3.0",
  "categories": {
    "breaking": [],
    "features": [],
    "fixes": [],
    "performance": [],
    "other": []
  },
  "contributors": [],
  "stats": {
    "total_commits": 42,
    "files_changed": 87,
    "insertions": 1234,
    "deletions": 567
  }
}

Edge Cases

•No tags exist: Use commit count or date range, warn user
•Non-conventional commits: Best-effort categorization from message content
•Monorepo: If user specifies a path, scope with git log -- path/
•Squash merges: Parse PR title from squash commit message
•Co-authored commits: Extract Co-authored-by trailers