Release 4.13.1

Changes from 4.13.0 to 4.13.1

A maintenance and performance follow-up to 4.13.0 focused on remote data
access and expanded platform support. Lazy access is now the default for remote
arrays and container datasets, local HDF5 files are read directly via h5py
without auxiliary dependencies, warm opens replay cached bootstrap metadata
to eliminate redundant network discovery, disk caches use human-readable
directory structures, and native Windows ARM64 wheels are now built and tested.

Improvements

Remote access

• Lazy access is the default for remote arrays and datasets. blosc2.open()
  on remote .b2nd files or container datasets (HDF5, Zarr, B2Z) now returns a
  lazy RemoteArray without requiring an explicit lazy=True. Dataset paths
  require lazy access and reject lazy=False with NotImplementedError rather
  than attempting a silent eager download. For standalone array files (such as
  .b2nd), cache_dir= keeps the default lazy access and persists fetched chunks
  in a RemoteArray carrier. Pass lazy=False to download the complete container
  there instead. mmap_mode= or a nonzero offset= forces the eager path.
• Direct local HDF5 reads via h5py. Local .h5/.hdf5 datasets are now
  read directly through h5py without requiring kerchunk, zarr, or
  fsspec. Chunked datasets retain their native HDF5 chunk layout, while
  contiguous datasets receive automatically chosen Blosc2 cache chunks. Dataset
  attributes are loaded from HDF5 metadata, and file handles are safely closed
  when the source object is garbage-collected. Explicit refs= arguments
  continue to select the kerchunk reference reader.
• Faster HTTP discovery and instant warm opens.
  • Cold HTTP B2Z discovery: Opening a remote B2Z archive over HTTP now
    retrieves the ZIP directory tail and remote object identity in a single
    bounded range request, halving network round-trips during initial open.
  • Warm reopens: Reopening cached B2Z, Zarr, or HDF5 sources replays persisted
    bootstrap metadata directly from the carrier file, completely bypassing
    remote discovery. Sibling HDF5 leaves from the same container under a shared
    cache_dir= reuse a single on-disk reference snapshot.
  • Whole-member prefetch for small B2Z arrays: Members up to 64 KiB are
    fetched in full on open (frame header, chunks, and trailing metadata in a
    single request). Prefetched chunks live in the standard chunk cache, count
    toward cache_bytes, respect max_cache_bytes, and can be evicted with
    trim_cache().

Readable disk caches

• Readable source directories for cache_dir=. Persistent disk caches now
  mirror the source filename and internal dataset hierarchy (e.g.,
  hierarchy.b2z--03cc6a2f9314/d0/a1.b2nd) with a 12-character identity
  fingerprint computed from the URL and storage options. Unsafe characters are
  escaped and long components are shortened. RemoteStore caches follow the
  same naming convention. Complete containers localized with lazy=False use
  it too (e.g., temperatures.b2nd--4908c5e5602a/temperatures.b2nd).
• Legacy hash-only cache entries are ignored rather than overwritten or deleted;
  the first open under 4.13.1 creates a new cache. Explicit cache_path= targets
  and direct opens of existing carrier files continue to work. Legacy cache
  directories can be safely deleted to reclaim disk space.

Packaging and platform support

• Windows ARM64 builds and wheels. Added native Windows on ARM64
  (win_arm64) wheel building and testing via GitHub Actions runners,
  including build configuration adjustments for Clang and runtime fallback for
  JIT on ARM64.
• CI test stability and doctest isolation. Enhanced test suite stability
  with logical core utilization in pytest-xdist, per-test workspace isolation
  for doctests in conftest.py, and test deadlock diagnostics.
• Remote lazy expression examples. Added examples/remote/lazy-expr.py
  and documentation illustrating how to evaluate lazy expressions across
  remote B2Z, Zarr, and HDF5 arrays.

Bug fixes

• Embedded frames with an offset. Opening a local file whose name looks
  like a container (.h5, .hdf5, .b2z, .zarr) with a nonzero offset
  now opens the embedded Blosc2 frame directly instead of attempting container
  parsing.
• file:// HDF5 URLs on Windows. Dataset path separators (::) in
  file:// URLs survive URL-to-path conversion on Windows platforms
  (e.g., file:///C:/path/x.h5::/d0/a2).
• Credential masking. RemoteArray.info and str() mask sensitive query
  parameters and credentials in signed URLs. RemoteArray.info now also works
  reliably for local B2Z sources without raising an error.
• load_tensor() eager access. Explicitly requests eager access so it no
  longer inadvertently returns a lazy RemoteArray intermediate when loading
  known remote paths.
• Blosc2-filtered HDF5 decoding. Fixed decoding of HDF5 datasets
  compressed with the Blosc2 filter (filter ID 32026, as written by
  hdf5plugin) when read via kerchunk. Chunks containing multi-chunk
  super-chunk frames decoded via blosc2.from_cframe() now handle the resulting
  bytes correctly, avoiding an AttributeError on .tobytes().
• HDF5 reference snapshot publishing. Guarded reference snapshot export so
  it is only published when the leaf carrier actually holds a kerchunk map,
  fixing a crash when opening local h5py sources with a disk cache on Windows
  drive-letter paths.
• Read-only portable carriers. Attaching a sparse runtime cache to a
  read-only legacy B2Z carrier no longer fails when refreshing bootstrap
  metadata; the session safely uses the rebuilt bootstrap in memory.