---
pretty_name: Dafny GitHub Dataset
license: other
license_name: mixed-see-license-field
language:
  - code
task_categories:
  - text-generation
tags:
  - dafny
  - formal-verification
  - program-verification
  - code
  - theorem-proving
size_categories:
  - 100K<n<1M
configs:
  - config_name: default
    data_files:
      - split: train
        path: data/train-*.parquet
---

# Dafny GitHub Dataset

A corpus of publicly available **Dafny** (`.dfy`) source code crawled from GitHub, packaged as
JSONL for model training and analysis. Dafny is a verification-aware programming language with
built-in specification constructs (pre/postconditions, invariants, `assert`/`assume`) checked by
an SMT solver.

- **106,404** unique-by-content `.dfy` files
- **966** source repositories (of 1,018 discovered; forks excluded)
- **753 MB** of source (stored as ~44 MB of zstd Parquet), median **5** files per repo
- Crawled **2026-07-22**

## Dataset structure

One JSON object per line:

| field            | type   | description                                             |
|------------------|--------|---------------------------------------------------------|
| `repo`           | string | `owner/name` of the source repository                   |
| `path`           | string | file path within the repo                               |
| `license`        | string | SPDX id of the repo's license, or `null`                |
| `stars`          | int    | repo stargazer count at crawl time                      |
| `default_branch` | string | branch the file was taken from                          |
| `commit_sha`     | string | commit / tree sha the file was read from                |
| `pushed_at`      | string | repo last-push timestamp (ISO 8601)                     |
| `size_bytes`     | int    | file size in bytes                                      |
| `sha256`         | string | SHA-256 of the file content (deduplication key)         |
| `content`        | string | full UTF-8 source of the `.dfy` file                    |

```python
from datasets import load_dataset
ds = load_dataset("hath995/DafnyGithub-Dataset", split="train")
print(ds[0]["repo"], ds[0]["path"])
print(ds[0]["content"])
```

## How it was built

1. **Discovery** — union of two GitHub channels: repo search `language:Dafny` (747 repos) and code
   search `extension:dfy` sliced by file size to beat the 1,000-result cap (surfacing `.dfy` files
   in otherwise non-Dafny repos). Forks are excluded (GitHub search excludes them by default).
2. **Extraction** — each repo shallow-cloned with a blobless partial + sparse checkout of `*.dfy`
   only (so a 2 GB repo pulls just its Dafny files). Repos that fail to check out on Windows
   (invalid paths, sparse-checkout edge cases) were recovered via the GitHub trees + raw-blob API.
3. **Deduplication** — files are deduplicated by exact content (`sha256`); ~117k exact duplicates
   were dropped during the crawl. Near-duplicates are **not** collapsed.

## Considerations for using the data

### Licensing

All files are included regardless of license; the `license` field records each repo's SPDX id so
you can filter per your needs. **A `null` or `NOASSERTION` value does not grant redistribution or
training rights** — filter accordingly before releasing or training.

Files by license: `null`/NONE 47,205 · NOASSERTION 33,730 · MIT 20,552 · Apache-2.0 3,880 ·
GPL-3.0 725 · BSD-2-Clause 94 · AGPL-3.0 73 · GPL-2.0 61 · BSD-3-Clause 33 · CC0-1.0 22 ·
BSL-1.0 12 · Unlicense 11 · CC-BY-4.0 4 · ISC 2. (`NOASSERTION` = a LICENSE file GitHub could not
map to an SPDX id.)

### Synthetic / benchmark corpora dominate the tail

A handful of repos are auto-generated verification benchmarks or LLM / mutation study data. They
account for a large share of files, and because each differs by only a token or two, exact-content
dedup does not collapse them:

| repo | files | nature |
|------|-------|--------|
| `VeriFixer/DSpec2Test` | 26,875 | generated spec→test benchmark |
| `ValentinaWu1112/…LLM-APR` | 11,119 | LLM program-repair attempts |
| `VeriFixer/DafnyFaultLoc` | 7,878 | fault-localization benchmark |
| `Beneficial-AI-Foundation/vericoding-benchmark` | 6,169 | vericoding benchmark |
| `MutDafny/mutdafny-study-data` | 4,652 | mutation-testing variants (partial: GitHub truncated the tree) |

For human-authored Dafny, filter these out:

```python
DROP = {
    "VeriFixer/DSpec2Test", "VeriFixer/DafnyFaultLoc",
    "ValentinaWu1112/Automated-Program-Repair-of-Arithmetic-Programs-in-Dafny-using-Large-Language-Models",
    "Beneficial-AI-Foundation/vericoding-benchmark", "MutDafny/mutdafny-study-data",
}
ds_human = ds.filter(lambda r: r["repo"] not in DROP)
```

## Limitations

- Snapshot of default branches at crawl time; no history, branches, or PRs.
- `mutdafny-study-data` is partial (GitHub truncated its recursive tree).
- Files larger than 2 MB were skipped.
- Coverage reflects GitHub's code-search index, which does not include every repo exhaustively.

## Provenance

Reproducible via the crawler scripts (`discover_repos.py`, `fetch_files.py`, `retry_api.py`).
Content belongs to the original repository authors under their respective licenses.