osobhandClaude Opus 5.5 0555794850 fix(format): read version-1 shared message addresses after the heap offset ...

A version-1 shared message (HDF5 1.6) embeds the target as a symbol-table
entry: after six reserved bytes comes a length-sized local-heap offset,
then the object header address. We read the heap offset as the address,
so datasets using a committed datatype in 1.6-era files (tcompound.h5,
tcompound2.h5) failed with InvalidObjectHeaderVersion. parse_shared_ref
now takes length_size and skips the offset, as libhdf5 does.

Resolving a reference also no longer falls back to the first message of
any type in the target header: a missing target message is
SharedMessageTargetMissing instead of garbage.

Fixture: tcompound.h5 from libhdf5's tools/test/testfiles (8 KiB).

Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>

2026-09-25 22:07:50 -05:00

8.0 KiB

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