[Debian-med-packaging] Bug#1149346: pynwb: FTBFS against python 3.15rc2 ('__cached__' not found in expected module structure)

[Margarita Manterola]

Package: src:pynwb
Version: 2.8.2-4
User: debian-python at lists.debian.org
Usertags: python3.15
Tags: ftbfs, forky, sid
Severity: important

Hi!

While rebuilding the python related packages against the Python 3.15rc2 
version we found that pynwb fails to build from source:
https://debusine.debian.net/debian/r-python-python3.15/artifact/4856659/

 From the log, the error seems to be:

   =================================== FAILURES 
===================================
   _______________ TestImportStructure.test_outer_import_structure 
________________
   […]
           for member in expected_structure:
   >           self.assertIn(member=member, container=current_structure)
   E           AssertionError: '__cached__' not found in ['BuildManager', 
'CORE_NAMESPACE', 'DataChunkIterator', 'H5DataIO', 'HDMFIO', 
'NWBContainer', 'NWBData', 'NWBDatasetSpec', 'NWBFile', 'NWBGroupSpec', 
'NWBHDF5IO', 'NWBNamespace', 'NamespaceCatalog', 'Path', 
'ProcessingModule', 'TimeSeries', 'TypeMap', '_HDF5IO', '__NS_CATALOG', 
'__TYPE_MAP', '__builtins__', '__doc__', '__file__', '__get_resources', 
'__io', '__loader__', '__name__', '__package__', '__path__', 
'__resources', '__spec__', '__version__', '_due', '_get_resources', 
'_version', 'available_namespaces', 'base', 'behavior', 'core', 
'deepcopy', 'device', 'docval', 'ecephys', 'epoch', 'file', 'get_class', 
'get_docval', 'get_loaded_type_config', 'get_manager', 
'get_nwbfile_version', 'get_type_map', 'getargs', 'h5py', 'hdmf', 
'hdmf_get_loaded_type_config', 'hdmf_load_type_config', 'hdmf_typemap', 
'hdmf_unload_type_config', 'icephys', 'image', 'io', 'legacy', 
'load_namespaces', 'load_type_config', 'misc', 'ogen', 'ophys', 'os', 
'popargs', 'register_class', 'register_map', 'resources', 'spec', 
'testing', 'unload_type_config', 'validate', 'warn']

This is very likely due to an explicit 3.15 change. From 
https://docs.python.org/3.15/whatsnew/3.15.html:

The __cached__ attribute on modules, which was deprecated since version 
3.13, is no longer set or taken into consideration by the import system 
or standard library. Use __spec__.cached instead. (Contributed by Brett 
Cannon in gh-97879.)

Setting the severity to important for now. Once Python 3.15 is released 
and later added to python3-defaults, this bug will become release 
critical.

-- 
Regards,
Marga