codewithbehnam/changelog

Generate a changelog for the changes since the last release:

1. Determine the range:

   • Check for existing tags: git tag --sort=-version:refname | head -5
   • If $ARGUMENTS contains --since <ref>, use that ref as the base
   • Otherwise use the most recent tag as the base: git describe --tags --abbrev=0
   • If there are no tags, use the first commit: git rev-list --max-parents=0 HEAD

2. Collect commits in the range:

   git log <base>..HEAD --pretty=format:"%H %s" --no-merges
   

3. Parse and categorize each commit by its conventional commit prefix:

   • feat: / feat(<scope>): -> Features
   • fix: / fix(<scope>): -> Bug Fixes
   • perf: / perf(<scope>): -> Performance Improvements
   • refactor: -> Internal Changes
   • docs: -> Documentation
   • test: -> Tests
   • chore: / ci: / build: -> Maintenance
   • BREAKING CHANGE: in commit body -> Breaking Changes (separate section at top)
   • Commits without a conventional prefix -> Uncategorized (include but note)

4. For each commit, fetch additional details if useful:

   • git show <hash> --stat to understand scope of change
   • Check for PR references (#NNN) in commit messages

5. Determine the version:

   • If $ARGUMENTS[0] looks like a version number (e.g., 1.2.0), use it
   • Otherwise, suggest a version based on the types of changes:
     • Any breaking change -> major bump
     • Any feat: commits -> minor bump
     • Only fix:/perf: -> patch bump

6. Format the changelog entry:

## [<version>] - <today's date>

### Breaking Changes
- Description of breaking change (commit abc1234)

### Features
- Short description of feature (commit abc1234)

### Bug Fixes
- Short description of fix (commit abc1234)

### Performance Improvements
- Short description (commit abc1234)

### Documentation
- Short description (commit abc1234)

### Maintenance
- Short description (commit abc1234)

7. Update CHANGELOG.md:

   • If the file exists, prepend the new entry after the title and any intro paragraph
   • If it does not exist, create it with a standard header and the new entry

8. Print the generated entry and the version recommendation.

Requirements

• Must be run inside a git repository with at least one commit
• Write access to CHANGELOG.md in the repository root

Error Handling

• If there are no commits since the last tag: report "No changes since <tag>" and stop
• If commits do not follow conventional format: include them under "Uncategorized" and suggest adopting conventional commits
• If CHANGELOG.md is very large: only update the top of the file, do not rewrite it