Files
clawhdf5/conformance/ref.py
T
osobhandClaude Opus 5.5 5c44630ea2 conformance: compare h5py's big-endian VL values corrected, confirm libhdf5 over-reads per run
The last 3 our-errors and 2 mismatches were documented as not ours but
still counted against us, on a heuristic (any big-endian VL mismatch) and
a fixed list.

- ref.py checks that the installed h5py returns big-endian VL elements
  with the file's bytes under a little-endian dtype (writing and reading
  a vlen('>f4') in memory) and, if so, relabels them with the file's byte
  order before hashing, marking the object `ref_fix`. The values are now
  compared: attr_datatypes.hdf5 /@vlen_uint64 and tcomplex_be.h5
  /VariableLengthDatasetFloatComplex are identical to ours (h5dump 1.14.6
  prints the same (1, 2), (3, 4, 5), (42)).
- ref_bugs.py re-reads each object h5py reads only through a libhdf5 bug
  in six processes with different heaps (import order, MALLOC_PERTURB_).
  Values the file determines are the same every time; these three change
  (6, 6 and 3 distinct results), so they are over-read memory, not data
  clawhdf5 could match. compare.py classifies a file `ref-bug` only when
  every difference is such an object confirmed in the same run.
- report.py: the ref-bug class, the evidence table, the corrected
  objects; test_ref.py covers both (run in the nightly job).

Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>
2026-09-27 22:26:32 -05:00

326 lines
11 KiB
Python
Executable File

#!/usr/bin/env python3
"""Reference probe: same JSON as the Rust `conformance-probe`, produced with h5py.
Walk: iterative DFS from '/', children in sorted (UTF-8 byte) name order, hard
links only, each object once (first path wins, deduplicated by object identity).
Canonical value encoding: see harness/src/main.rs.
"""
import hashlib
import json
import os
import struct
import sys
import numpy as np
import h5py
try:
import hdf5plugin # noqa: F401 registers blosc/lz4/zstd/bzip2/... filters
except Exception: # pragma: no cover
pass
MAX_BYTES = 200 * 1024 * 1024
MAX_OBJECTS = 200_000
def canon_str(b, out):
if isinstance(b, str):
b = b.encode("utf-8", "surrogateescape")
b = bytes(b)
cut = b.find(b"\x00")
if cut >= 0:
b = b[:cut]
b = b.rstrip(b" ")
out += b"S" + struct.pack("<I", len(b)) + b
def simple(dt):
if dt.fields:
return all(simple(dt.fields[n][0]) for n in dt.names)
if dt.subdtype:
return simple(dt.subdtype[0])
return dt.kind in "iufcbV"
def packed(dt):
if dt.fields:
return np.dtype([(n, packed(dt.fields[n][0])) for n in dt.names])
if dt.subdtype:
base, shape = dt.subdtype
return np.dtype((packed(base), shape))
if dt.kind in "iufcb":
return dt.newbyteorder("<")
return dt
# --- reference corrections ---------------------------------------------------
# Where h5py is known to return values the file does not hold, and the right
# values follow from what it returned, ref.py corrects them and records the
# correction on the object ("ref_fix"), so the comparison is still a real
# comparison and CONFORMANCE.md lists every corrected object. Each correction
# first checks that the installed h5py still has the bug.
# Corrections applied while encoding the current object.
FIXES = set()
_BE_VLEN_BUG = None
def be_vlen_bug():
"""h5py (3.16 / HDF5 2.0 at least) returns the elements of a
variable-length sequence whose base type is big-endian with the file's
big-endian bytes under a native (little-endian) dtype: a
`vlen_dtype('>f4')` dataset holding [1.0, 2.0] reads back as
[4.6e-41, 9.0e-44]. `h5dump` prints the file's values. Checked once per
process by writing and reading exactly that dataset in memory."""
global _BE_VLEN_BUG
if _BE_VLEN_BUG is None:
import io
try:
bio = io.BytesIO()
with h5py.File(bio, "w") as f:
d = f.create_dataset("v", (1,), dtype=h5py.vlen_dtype(np.dtype(">f4")))
d[0] = np.array([1.0, 2.0], dtype=">f4")
with h5py.File(bio, "r") as f:
got = np.asarray(f["v"][0])
_BE_VLEN_BUG = (got.dtype == np.dtype("<f4")
and got.view(">f4").tolist() == [1.0, 2.0]
and got.tolist() != [1.0, 2.0])
except Exception: # noqa: BLE001
_BE_VLEN_BUG = False
return _BE_VLEN_BUG
def unswapped(got, base):
"""`got` is `base` (big-endian somewhere) with every field in native
little-endian order instead: the shape of h5py's big-endian VL bug."""
return base.newbyteorder("<") == got and base != got
def canon_el(dt, val, out):
if dt.fields:
for n in dt.names:
canon_el(dt.fields[n][0], val[n], out)
return
if dt.subdtype:
base, _ = dt.subdtype
for x in np.asarray(val).reshape(-1):
canon_el(base, x, out)
return
k = dt.kind
if k in "iufcb":
out += np.asarray(val, dtype=dt).astype(dt.newbyteorder("<")).tobytes()
elif k == "V":
out += np.asarray(val, dtype=dt).tobytes()
elif k == "S":
canon_str(val, out)
elif k == "O":
if h5py.check_string_dtype(dt) is not None:
canon_str(val if val is not None else b"", out)
elif h5py.check_ref_dtype(dt) is not None:
out += b"R"
else:
base = h5py.check_vlen_dtype(dt)
if base is None:
raise TypeError(f"unhandled object dtype {dt!r}")
arr = np.asarray(val if val is not None else [])
if arr.dtype != base and be_vlen_bug() and unswapped(arr.dtype, base):
# h5py's big-endian VL bug (see be_vlen_bug): the bytes are
# the file's, the dtype label is wrong. Relabel, don't convert.
arr = arr.view(base)
FIXES.add("h5py-be-vlen")
arr = np.asarray(arr, dtype=base).reshape(-1)
out += b"V" + struct.pack("<I", arr.shape[0])
if simple(base):
out += arr.astype(packed(base)).tobytes()
else:
for x in arr:
canon_el(base, x, out)
elif k == "U":
canon_str(str(val), out)
else:
raise TypeError(f"unhandled dtype kind {k} ({dt!r})")
def has_obj(dt):
if dt.fields:
return any(has_obj(dt.fields[n][0]) for n in dt.names)
if dt.subdtype:
return has_obj(dt.subdtype[0])
return dt.kind == "O"
def note_conversion(tid, dt, rec):
"""h5py converts some file types (FP8, bfloat16, x87 long double, ...) to a
different-sized numpy type; then value bytes are not comparable."""
try:
if not has_obj(dt) and tid.get_size() != dt.itemsize:
rec["converted"] = f"file type size {tid.get_size()} -> numpy {dt} ({dt.itemsize})"
except Exception: # noqa: BLE001
pass
def hash_values(arr, dt, rec):
# h5py expands an HDF5 array element type into trailing array dims, a
# nested array type (an array of arrays) into all of them. Converting the
# expanded array back to the inner subarray type would broadcast every
# element into a whole subarray, so strip every level.
while dt.subdtype is not None:
dt = dt.subdtype[0]
arr = np.asarray(arr, dtype=dt)
FIXES.clear()
if simple(dt):
c = np.ascontiguousarray(arr).astype(packed(dt)).tobytes()
else:
out = bytearray()
for x in arr.reshape(-1):
canon_el(dt, x, out)
c = bytes(out)
if FIXES:
rec["ref_fix"] = sorted(FIXES)
rec["hash"] = hashlib.sha256(c).hexdigest()
rec["head"] = c[:48].hex()
def err(e):
s = f"{type(e).__name__}: {e}"
return s.splitlines()[0][:400] if s else type(e).__name__
def shape_of(s):
return "null" if s is None else list(s)
def n_bytes(shape, tid):
n = 1
for d in shape or ():
n *= d
return n * tid.get_size()
def read_attrs(obj):
out = {}
names = sorted(obj.attrs.keys(), key=lambda s: s.encode("utf-8", "surrogateescape"))
for name in names:
rec = {}
try:
aid = obj.attrs.get_id(name)
rec["dtype"] = str(aid.dtype)
rec["shape"] = shape_of(aid.shape)
note_conversion(aid.get_type(), aid.dtype, rec)
if aid.shape is None:
hash_values(np.empty((0,), dtype=aid.dtype), aid.dtype, rec)
else:
val = obj.attrs[name]
hash_values(val, aid.dtype, rec)
except Exception as e: # noqa: BLE001
rec = {"error": err(e)}
out[name] = rec
return out
def main(path):
top = {"file": path}
try:
f = h5py.File(path, "r")
except Exception as e: # noqa: BLE001
top["open_error"] = err(e)
print(json.dumps(top))
return
objects = []
seen = set()
# Objects h5py cannot open have no ObjectID to deduplicate by; they are
# deduplicated by the address their hard link points at instead, as the
# probe deduplicates every object by header address.
seen_unopenable = set()
stack = [("/", None, None)]
while stack:
p, obj, link_addr = stack.pop()
if len(objects) >= MAX_OBJECTS:
top["truncated"] = True
break
rec = {"path": p}
try:
if obj is None:
obj = f[p]
key = hash(obj.id) # h5py ObjectID hash = (fileno, object address/token)
except Exception as e: # noqa: BLE001
if link_addr is not None:
if link_addr in seen_unopenable:
continue
seen_unopenable.add(link_addr)
rec["kind"] = "unknown"
rec["error"] = err(e)
objects.append(rec)
continue
if key in seen:
continue
seen.add(key)
if isinstance(obj, h5py.Dataset):
kind = "dataset"
elif isinstance(obj, h5py.Group):
kind = "group"
elif isinstance(obj, h5py.Datatype):
kind = "datatype"
else:
kind = "unknown"
rec["kind"] = kind
if kind == "dataset":
try:
dt = obj.dtype
rec["dtype"] = str(dt)
rec["shape"] = shape_of(obj.shape)
note_conversion(obj.id.get_type(), dt, rec)
if obj.shape is None:
hash_values(np.empty((0,), dtype=dt), dt, rec)
elif n_bytes(obj.shape, obj.id.get_type()) > MAX_BYTES:
rec["skipped"] = "too large"
else:
arr = np.empty(obj.shape, dtype=dt)
if arr.size:
try:
obj.read_direct(arr)
except Exception: # noqa: BLE001
arr = obj[()]
hash_values(arr, dt, rec)
except Exception as e: # noqa: BLE001
rec["error"] = err(e)
if kind != "datatype":
try:
rec["attrs"] = read_attrs(obj)
except Exception as e: # noqa: BLE001
rec["attrs_error"] = err(e)
if kind == "group":
try:
names = sorted(obj.keys(), key=lambda s: s.encode("utf-8", "surrogateescape"))
base = "" if p == "/" else p
kids = []
for n in names:
# The link's own type: `obj.get(n, getlink=True)` reports
# a user-defined link (type 64-255) as a HardLink.
try:
info = obj.id.links.get_info(n.encode("utf-8", "surrogateescape"))
except Exception: # noqa: BLE001
info = None
if info is not None and info.type != h5py.h5l.TYPE_HARD:
continue
addr = info.u if info is not None else None
kids.append((f"{base}/{n}", addr))
for k, addr in reversed(kids):
stack.append((k, None, addr))
except Exception as e: # noqa: BLE001
rec["list_error"] = err(e)
objects.append(rec)
top["objects"] = objects
print(json.dumps(top), flush=True)
# Exit without tearing down the h5py objects: freeing them for some files
# that hold references (hdf5's h5repack_attr_refs.h5, cve-2024-32623.h5)
# makes libhdf5 2.0 abort with "free(): chunks in smallbin corrupted"
# about half the time. That happens after the reading is done, so it says
# nothing about what h5py read, but it flipped those files between ok and
# h5py-cannot-read from one run to the next.
os._exit(0)
if __name__ == "__main__":
main(sys.argv[1])