With libver='latest', a chunked dataset with two or more unlimited dimensions
indexes its chunks with a v2 B-tree (layout v4, index type 5). Reading one
failed with "unsupported chunked layout version=4, index_type=Some(5)".
read_btree_v2_chunks decodes record types 10 (address + scaled offsets) and 11
(address, stored size, filter mask, scaled offsets). The width of the
stored-size field is taken from the record size the tree header declares
rather than re-deriving the library's formula. Scaled offsets are multiplied
back by the chunk dimensions with overflow checks.
The chunk-index dispatch existed four times (uncached, cached, sweep and
indexed readers). The three copies outside list_chunks now call it, so every
read path — and fill-value handling and partial reads — supports every index
type from one place.
h5py interop test: plain, gzip+shuffle, a 2500-chunk tree with internal nodes,
a sparse dataset with a fill value, and a strided hyperslab.
Co-Authored-By: Claude Fable 5.1 <[email protected]>
