Complex dtypes lost when writing V2 arrays

[martindurant]

Zarr version

3.0.1++

Numcodecs version

Python Version

3.12

Operating System

linux

Installation

manual from source

Description

Compound dtypes ("records") are allowed by numpy and worked in V2. They now loose their internal structure.

Steps to reproduce

The following passes on v2, not on v3

g = zarr.open(mode="w", zarr_version=2)
arr = g.create_array("name", dtype=[('a', "i8"), ('b', 'f8')], shape=(1, ), chunks=(1,), compressor=None, overwrite=True)
arr2 = g["name"]
assert arr2.dtype == [('a', '<i8'), ('b', '<f8')]

The v3 dtype comes back as dtype('V16').

Additional output

No response

[d-v-b]

xref #2134

[d-v-b]

i think #2681 will fix this

[martindurant]

Sorry, I should have checked for similar reports

[d-v-b]

no worries! the volume of issues related to any given problem is so far a good informal measure of severity.