# Conformance sweep

Reads every HDF5 file of eight public corpora with clawhdf5 and with
h5py/libhdf5, compares the two readings object by object, and writes
[`CONFORMANCE.md`](../CONFORMANCE.md).

```sh
CLAWHDF5_PYTHON=/path/to/venv/bin/python conformance/run.sh      # ~30 s once the corpus is cached
conformance/run.sh --update-baseline                             # after an intended change in results
```

Needs Rust, `git`, `h5dump` (Debian/Ubuntu `hdf5-tools`), `libaec` (for the
probe's `szip` feature; `libaec-dev`), and a Python with the packages in
`requirements.txt`. The first run downloads about 450 MB of sparse checkouts.

| file | role |
|---|---|
| `corpus.txt` | the corpora: git URL, pinned commit, swept root, sparse-checkout patterns |
| `fetch-corpus.sh` | shallow, sparse, blob-filtered checkout of each pinned commit into `.cache/src/` (gitignored); no-op when already there |
| `list_files.py` | which files are probed (HDF5/netCDF-4 extensions minus netCDF classic, plus the CVE reproducers) |
| `probe/` | the clawhdf5 side: a standalone crate (outside the workspace, so `cargo test --workspace` never builds it) that walks a file with `clawhdf5-format` and prints canonical JSON |
| `ref.py` | the h5py side: the same JSON from h5py |
| `run_one.sh` | runs both sides on one file (and `h5dump` on the CVE corpus) under a timeout and an address-space limit |
| `compare.py` | classifies each file (ok / our-error / mismatch / h5py-cannot-read / panic / hang / crash / oom) and groups root causes |
| `report.py` | writes `CONFORMANCE.md` |
| `check.py` | the gate: fails on any panic/hang/crash/oom, on an ok count below `baseline.json`, or on a baseline-ok file that is no longer ok |
| `baseline.json` | the ok files the gate holds the line on |
| `requirements.txt` | pinned h5py / numpy / hdf5plugin / netCDF4 |

Results for every file (both sides' JSON and stderr, `results.csv`,
`results.json`, `summary.md`) are left in `.cache/results/`.

The nightly job is `.gitea/workflows/conformance.yml`; it prints the report
into the job log.

The canonical value encoding both sides hash is documented at the top of
`probe/src/main.rs`. Values are compared as libhdf5 presents them: a float
with a non-IEEE bit layout (N-Bit) or an integer with a bit offset is compared
as the converted number, not as raw file bytes.