README.md

---
language:
- en
tags:
- code
- git
- commit-messages
- typescript
- conventional-commits
- fine-tuning
pretty_name: Git Diff → Conventional Commit Messages (TypeScript)
size_categories:
- 10K<n<100K
task_categories:
- text-generation
- summarization
---

# Git Diff → Conventional Commit Messages

A dataset of 12,433 `(git diff, commit message)` pairs scraped from real open-source TypeScript repositories, filtered for quality and formatted for fine-tuning small language models to generate [Conventional Commits](https://www.conventionalcommits.org/).

Built as part of a project to fine-tune a local LLM to write commit messages as a `prepare-commit-msg` git hook. Full write-up: [eliotbas.com/projects/commits-fine-tuning](https://eliotbas.com/projects/commits-fine-tuning/)

## Dataset details

### Source repositories

13 open-source TypeScript repositories selected for commit discipline and diversity:

- **Libraries**: Vite, Vitest, Vue.js core, Angular, tRPC, TanStack Query
- **Apps/platforms**: Supabase, Nuxt, Twenty, Prisma, TypeORM
- **Tooling**: typescript-eslint, commitlint
- **Workflow-specific**: Botpress OSS (to match the author's internship codebase)


### Format

JSONL, chat format. Each example has a `messages` field with two turns:

```json
{
  "messages": [
    {
      "role": "user",
      "content": "diff --git a/src/index.ts b/src/index.ts\n..."
    },
    {
      "role": "assistant",
      "content": "feat(core): add retry logic for failed requests"
    }
  ],
  "meta": {
    "repo": "vitejs/vite",
    "hash": "496a63ad5af3b9e5a7bba5477057f1e61a267a70"
  }
}
```

## Filtering and quality criteria

Not every commit was kept. The main filters applied:

- **Conventional Commits enforcement** — message must match `type(scope)?: description` format
- **Trailing ref stripping** — `(#1234)` references removed; not inferable from the diff and would be learned as hallucination fodder
- **Generated-file exclusion** — each commit must touch at least one non-generated file (lockfiles, minified JS, `dist/`, snapshots excluded)
- **Per-repo cap** — prevents large repos (e.g. Angular) from dominating the distribution
- **Length filter** — too small and too big commits are filtered

## Commit type distribution

| Type | Share |
|------|-------|
| fix | ~30% |
| chore | ~18% |
| docs | ~14% |
| feat | ~13% |
| test | ~8% |
| refactor | ~7% |
| ci / build / perf / style | ~10% combined |

## Key statistics

| Metric | Value |
|--------|-------|
| Commit message length (p50) | 54 chars |
| Commit message length (p95) | 91 chars |
| Diff length (p50) | 2,024 chars |
| Diff length (p95) | 7,827 chars |

## Intended use

Designed for LoRA fine-tuning of small code language models (0.5B–3B parameters) on the task of generating a single Conventional Commit message from a `git diff --staged` output.

Models fine-tuned on this dataset were evaluated in the accompanying article. Best results with:
- Qwen2.5-Coder-0.5B-Instruct
- Qwen2.5-Coder-1.5B-Instruct
- Qwen2.5-Coder-3B-Instruct

## Limitations

- **TypeScript-specific**: sourced entirely from TypeScript repos; may not generalize to other languages or mixed codebases
- **High-discipline repos only**: all source repos follow Conventional Commits strictly; behavior on messier codebases is untested
- **Diff-only context**: the model sees only the diff, not the ticket, PR description, or broader codebase context — the human author always had more information


## Related resources

- Article: [eliotbas.com/projects/commits-fine-tuning](https://eliotbas.com/projects/commits-fine-tuning/)
- GitHub (scraping scripts, training and evaluation code, git hook): [github.com/Elib27/commits-fine-tune](https://github.com/Elib27/commits-fine-tune)
- Fine-tuned models: *(HuggingFace model links)*