Shape and chunks accept float values when creating an array

[faymanns]

Zarr version

v2.18.3

Numcodecs version

v0.12.1

Python Version

v3.11.2

Operating System

Linux

Installation

Using pip into virtual environment

Description

When you create a new array (e.g. using zarr.zeros), the tuples for shape and chunks can contain float values.
The values after the decimal point are trimmed without a warning.
Is this the intended behavior?
I would expect zarr-python to raise an exception or at least a warning.

Steps to reproduce

import zarr

z = zarr.zeros((100.4, 100.9), chunks=(10.5, 10.1), dtype="i4")
print(z.shape)
print(z.chunks)

As you can see from the output the float values are trimmed without warning:

(100, 100)
(10, 10)

Additional output

No response

[d-v-b]

Thanks for the bug report; we are working on version 3 of zarr-python so I don't think we are going to make any more releases in the 2.x series. I did test this in zarr-python==3.0.0b2:

Shape fails as expected:

>>> zarr.ones((10, 10.0))
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/Users/bennettd/.pyenv/versions/3.11.9/lib/python3.11/site-packages/zarr/api/synchronous.py", line 264, in ones
    return Array(sync(async_api.ones(shape, **kwargs)))
                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/bennettd/.pyenv/versions/3.11.9/lib/python3.11/site-packages/zarr/core/sync.py", line 141, in sync
    raise return_result
  File "/Users/bennettd/.pyenv/versions/3.11.9/lib/python3.11/site-packages/zarr/core/sync.py", line 100, in _runner
    return await coro
           ^^^^^^^^^^
  File "/Users/bennettd/.pyenv/versions/3.11.9/lib/python3.11/site-packages/zarr/api/asynchronous.py", line 1037, in ones
    return await create(shape=shape, fill_value=1, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/bennettd/.pyenv/versions/3.11.9/lib/python3.11/site-packages/zarr/api/asynchronous.py", line 907, in create
    return await AsyncArray.create(
           ^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/bennettd/.pyenv/versions/3.11.9/lib/python3.11/site-packages/zarr/core/array.py", line 458, in create
    shape = parse_shapelike(shape)
            ^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/bennettd/.pyenv/versions/3.11.9/lib/python3.11/site-packages/zarr/core/common.py", line 145, in parse_shapelike
    raise TypeError(msg)
TypeError: Expected an iterable of integers. Got (10, 10.0) instead.

But we do accept a float for chunks, which we should fix:

>>> zarr.ones((10,10), chunks=(2, 2.0))
<Array memory://4409673920 shape=(10, 10) dtype=float64>

[faymanns]

Thanks for the reply @d-v-b! I'd be happy to submit a pull request for the chunks following the way the shape input is parsed.
I guess parsing the input for chunks and chunk_shape with parse_shapelike inside create should be sufficient?

[d-v-b]

yes that sounds like the right direction.

[dstansby]

Thanks for the bug report; we are working on version 3 of zarr-python so I don't think we are going to make any more releases in the 2.x series

@d-v-b I thought we were supporting verseion 2 for (at least) six months after release of version 3? So I think it would be reasonable to fix this in the version 2 branch, and I'd be happy to review a PR to version 2 and do a bugfix release.

[d-v-b]

@dstansby that makes sense! In that case we should fix 2.x and 3.x

[faymanns]

My PR for the main branch has been merged. Should I submit another PR for the v2 branch before closing this issue?

[dstansby]

A PR to the v2 branch would be great - I would say that instead of raising an error, we should raise a warning on the v2 branch because an error would technically be a breaking change.

[faymanns]

Sorry that it took me so long to do this. I created a pull request (#2579) for v2 that raises warnings.
@dstansby could you take a look at it? I didn't find a logger in v2 so I used the warnings module.

[faymanns]

Fixed for v3 in #2535 and fixed for v2 in #2579.