commitgen

conventional-commit messages from your staged diff. no llm, no api key, no tokens. just regexes and path matching.

what it is

i got tired of writing chore: stuff at 2am, and i didn't want to pipe my diff to a model every time i make a commit. so this is about 400 lines of python that reads git diff --cached, runs a pile of rules over it, and prints something like feat(auth): add login flow. heuristics are dumb but mostly right, which is the bar i set.

install

pip install git+https://github.com/f4rkh4d/commitgen

needs python 3.10+ and git on your PATH.

usage

$ git add src/auth/login.py
$ commitgen
feat(auth): add login

$ commitgen --body
feat(auth): add login

- add login
- new src/auth/login.py

$ commitgen --no-scope
feat: add login

$ commitgen --type chore
chore: add login

$ commitgen --commit
# runs `git commit -m "feat(auth): add login"` for you

if nothing is staged, it exits 1 and tells you to git add something. reasonable.

how it decides

• if every changed file is under tests/, or matches test_*.py / *_test.go / *.test.ts, it's test
• if every file is *.md, README, docs/, LICENSE or CHANGELOG, it's docs
• workflows under .github/workflows/, Dockerfile, .gitlab-ci.yml, CircleCI, Travis → ci
• only manifests like pyproject.toml, package.json, Cargo.toml, go.mod, lockfiles → chore
• whitespace-only diff → style
• no new symbols + small diff + path has words like "fix"/"bug"/"patch" → fix
• new def/class/fn/func added and decent additions → feat
• nothing obvious, medium-sized diff → refactor
• fallback → chore

scope comes from the longest shared first-directory segment across staged files, ignoring a top-level src/, lib/, app/, pkg/, internal/. if files span multiple roots you don't get a scope. subject line picks the first newly-added symbol and humanizes it (UserSession → user session). 60-char cap.

honest caveats

• heuristics are dumb. if you've got 50 files staged across 5 concerns, it'll pick one and look confused.
• the subject line is a guess from the first new symbol. if that symbol is __init__, you'll get something lukewarm.
• i haven't tested on windows. pretty sure subprocess + git work there but i'm not volunteering.
• binary diffs are skipped from analysis. they still count for scope detection.

dev

git clone https://github.com/f4rkh4d/commitgen
cd commitgen
python -m venv .venv && . .venv/bin/activate
pip install -e '.[dev]'
pytest -q

license

MIT. see LICENSE.