Error using Zarr.pySetup

[ehennestad]

I am getting the following error in Zarr.pySetup:

Error using six>__get__
Python Error: AttributeError: 'NoneType' object has no attribute 'BaseHTTPServer'

It is triggered by the following line:

MATLAB-support-for-Zarr-files/Zarr.m

Line 52 in 0c96a28

loadedModules = dictionary(sys.modules);

I have not explored which module in my environment causes this message

[jm9176]

Hi @ehennestad, could you please share the repro steps and MATLAB release (e.g. R2025a) info?

EDIT: Also share the OS info

[ehennestad]

I tried to reproduce this, but getting another error:

Error using dictionary/isKey
Unable to use 'string' as key for dictionary with 'cell' key type.

Error in Zarr.pySetup (line 53)
            if ~loadedModules.isKey("ZarrPy")

Error in Zarr (line 76)
            Zarr.pySetup;

Error in zarrread (line 14)
zarrObj = Zarr(filepath);

Caused by:
    Error using cell
    Conversion to cell from string is not possible.

This is MATLAB R2023b, it works on R2025a

[abhibaruah]

Hello @ehennestad
Can you share the reproduction steps along with the OS information?

[ehennestad]

I get the same error if I run this in R2023b

rootFolder = fileparts( mfilename("fullpath") );
root_zarr_folder = fullfile('test.zarr', 'groupA', 'groupB');
zarrcreate(root_zarr_folder, [100,100]) 

macOS 15.4.1

[abhibaruah]

In R2023b, conversion of a MATLAB dictionary to a Python dictionary is not supported. Which is why you are seeing this error.

For example, even this code fails iN R2023b but passes from R2024a onwards:

X = dictionary(["A", "B"], ["a", "b"]);
Y = py.dict(X)

I know we have mentioned that the minimum release is R2022b, but I suppose there are still a few things we need to iron out. The newer the MATLAB release, the better the support.