NumPy 2 support

[quasiben]

To assist reproducing bugs, please include the following:

• Operating System: Mac 14.4.1 (23E224))
• Python version: 3.11
• Where Python was acquired (e.g. system Python on MacOS or Linux, Anaconda on
  Windows)
• h5py version: 3.11
• HDF5 version: 1.14.3

I'm testing out a variety of pydata tools (as part of dask testing) with the release candidate for NumPy 2: 2.0.0rc1 . I'm getting an error on import of h5py and NumPy 2 installed. I searched the tracker and couldn't find anything related to NumPy 2 testing so I filed this to start the discussion.

╰─$ python -c 'import h5py'
Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "/Users/bzaitlen/miniforge3/envs/test-environment/lib/python3.11/site-packages/h5py/__init__.py", line 45, in <module>
    from ._conv import register_converters as _register_converters, \
  File "h5py/_conv.pyx", line 1, in init h5py._conv
  File "h5py/h5r.pyx", line 1, in init h5py.h5r
  File "h5py/h5p.pyx", line 1, in init h5py.h5p
ValueError: numpy.dtype size changed, may indicate binary incompatibility. Expected 96 from C header, got 88 from PyObject

[jakirkham]

Thanks Ben! 🙏

How did you install h5py?

[quasiben]

Through conda-forge:

h5py 3.11.0 nompi_py311hd00467f_100 conda-forge

[jakirkham]

Think the conda-forge h5py won't work in this case as it hasn't been rebuilt with NumPy 2 yet. There is a plan to do so ( conda-forge/conda-forge-pinning-feedstock#5790 ), which likely starts soon

In the interim, maybe it is worth trying h5py wheels (assuming they have been built with NumPy 2)?

[tacaswell]

I believe the pre-release wheels have been built with numpy2 but the released ones have not. I could be wrong about that though.

If you want to test numpy2 it is probably best to install h5py either from the repo of via pip install --no-build-isolation --no-binary h5py h5py.

[quasiben]

Thanks @tacaswell ! The pip install command you noted worked. Closing