read_string, read_string_bytes, read_string_selection, read_vlen and
read_vlen_selection now retry as a whole, the global-heap decoding after the
read included; so do File::decode_strings / decode_string_bytes /
decode_vlen, Group::datasets / groups / attrs / attr, Dataset::attrs / attr,
the typed full reads (read_f64 ...), the header messages behind shape() and
dtype() (a shared message is read from another header), and
verify_provenance. Before, a transient failure on those reached the caller.
Attribute reads leave out an attribute they cannot read (or return a
variable-length string one as AttrValue::Raw) instead of failing, which hid
a transient error as a missing or raw attribute: on a live file such an
error of a retried kind now runs the read again too, and after the last
attempt the last result is returned as before. The format crate gains
find_attribute_reporting_in, which returns the errors find_attribute_in
skips (dense name-index lookups dropped them). The zero-copy reads need the
file in memory, which a live file never is, so they have nothing to retry.
Test: a storage that fails one read with a checksum mismatch; for 14 read
paths over a new fixture (tests/fixtures/swmr_strings_attrs.h5, an h5py
copy with the SWMR-write flag: vlen strings, vlen int32, dense attributes),
each read the path makes fails once in turn and the path must return the
same result with exactly one retry. It fails on the previous commit
(root.attrs, read 0). Dataset::attr on dense attributes returned None
before find_attribute_reporting_in.
Co-Authored-By: Claude Opus 5.5 (1M context) <[email protected]>
