Bug#1122011: python3-numcodecs: incompatible to Python3.14

[Antonio Valentino]

Dear Ole,

On Fri, 5 Dec 2025 19:53:10 +0100 Ole Streicher <olebole at debian.org> wrote:
> Package: python3-numcodecs
> Version:  0.16.5+ds-1
> Severity: serious
> Control: affects -1 src:sunpy
> 
> With Python 3.14, numcodecs cannot be imported anymore:
> 
> $ python3.14
> Python 3.14.0 (main, Dec  1 2025, 11:18:59) [GCC 15.2.0] on linux
> Type "help", "copyright", "credits" or "license" for more information.
>  >>> import numcodecs
> Traceback (most recent call last):
>    File "<python-input-0>", line 1, in <module>
>      import numcodecs
>    File "/usr/lib/python3/dist-packages/numcodecs/__init__.py", line 43, 
> in <module>
>      from numcodecs import blosc
> ImportError: cannot import name 'blosc' from partially initialized 
> module 'numcodecs' (most likely due to a circular import) 
> (/usr/lib/python3/dist-packages/numcodecs/__init__.py)
> 
> This blocks the compilation of (the new version of) Sunpy.

I have the same issue with satpy but I think that the issue is just that 
numcodecs has been not re-built yet to generate the extension modules 
for Python 3.14.

It is indeed part of the python3.14-add transition: 
https://release.debian.org/transitions/html/python3.14-add.html

I can confirm that the package builds perfectly locally (x86_64).



kind regards
-- 
Antonio Valentino