cannot import name 'cbuffer_sizes' from 'numcodecs.blosc'

Hi,

It looks like the latest released version 0.16.0 is not compatible with zarr < 3. It gives me

/usr/share/miniconda/envs/ome_zarr_converter/lib/python3.11/site-packages/zarr/util.py:34: in <module>
    from numcodecs.blosc import cbuffer_sizes, cbuffer_metainfo
E   ImportError: cannot import name 'cbuffer_sizes' from 'numcodecs.blosc' (/usr/share/miniconda/envs/ome_zarr_converter/lib/python3.11/site-packages/numcodecs/blosc.cpython-311-x86_64-linux-gnu.so)

Thanks!

I run into this in https://github.com/pipefunc/pipefunc as well.

Pinning to <0.16 seems to fix it.

MAINT: Pin zarr-developers/numcodecs#721

This is likely due to removal of deprecated functions in PR: #712

Looks like Zarr still needs an update to drop these names: zarr-developers/zarr-python#2963

Solution #733

Pin numcodecs <0.16.0 for zarr 3 compatibility. See zarr-developers/n…

(Again) Pin numcodecs <0.16.0 for zarr 3 compatibility. See zarr-deve…

Improve Swagger doc (fix numcodecs==0.15.1 issue zarr-developers/numc…

Bump Zarr version

oh hoh, ping on this anniversary + 2 weeks .

Remove cap for numcodecs

A user from one of my libraries ran into this issue recently as well:

Traceback (most recent call last):
  File "C:\Users\username\redacted\main.py", line 4, in <module>
    import xscen
...
ImportError: cannot import name 'cbuffer_sizes' from 'numcodecs.blosc' (C:\ProgramData\anaconda3\envs\env_name\Lib\site-packages\numcodecs\blosc.cp313-win_amd64.pyd)

Downgrading numcodecs seemed to be the workaround.

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cannot import name 'cbuffer_sizes' from 'numcodecs.blosc' #721

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cannot import name 'cbuffer_sizes' from 'numcodecs.blosc' #721

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basnijholt commented on Apr 7, 2025

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