osobhandClaude Opus 5.5
6559a91495
For a metadata cache image libhdf5 cannot load, libhdf5 opens the file and fails the first metadata read (the image loads on the first H5C_protect after open); h5py reports the error on the root group. The conformance probe reported it that way, but File::open refused the file, so the gate counted cve-2025-6269-1..4 and cve-2025-6516 as agreeing with h5py for behaviour the library did not have. The library now behaves as the probe reports: File (mmap, buffered and from_bytes) and MmapFile open the file and every object lookup (dataset, dataset_at, group, group listings and attributes, VL decoding) fails with the image's error; LazyFile reads the root group's header at open, so its open is that first read and fails. Probe and library take the three-way decision (refuse at open / image loads / image cannot load) from the same clawhdf5_format::superblock_ext::cache_image_state. One deliberate difference from libhdf5 remains, documented: after the failed first read libhdf5 reads the file's own metadata, which the image was meant to replace and may be stale; here every lookup keeps failing. File::cache_image_error / MmapFile::cache_image_error expose the error to code that parses as_bytes() itself; h5rs checks it before reading any object header (h5rs ls on cve-2025-6269-1 said "invalid object header version: 0" from the stale bytes). Test: metadata_cache_image.rs an_image_libhdf5_cannot_load_fails_every_object (the fixture with its image signature broken; h5py opens that file and fails the first read with "Bad metadata cache image header signature"). It fails on the previous commit, where File::open refuses the file. Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>
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.
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.