Bug 2345536

Summary: h5py fails to import with Python 3.14: ValueError: chr() arg not in range(0x110000)
Product: [Fedora] Fedora Reporter: Ben Beasley <code>
Component: h5pyAssignee: Terje Rosten <terjeros>
Status: CLOSED WORKSFORME QA Contact: Fedora Extras Quality Assurance <extras-qa>
Severity: medium Docs Contact:
Priority: unspecified    
Version: rawhideCC: orion, steve.traylen, terjeros
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OS: Linux   
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Last Closed: 2025-03-14 12:54:15 UTC Type: ---
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Bug Blocks: 2322407, 2345530, 2345531    

Description Ben Beasley 2025-02-13 12:29:36 UTC 
h5py fails to import with Python 3.14.

# python3 -c 'import h5py'
Traceback (most recent call last):
  File "<string>", line 1, in <module>
    import h5py
  File "/usr/lib64/python3.14/site-packages/h5py/__init__.py", line 45, in <module>
    from ._conv import register_converters as _register_converters, \
                       unregister_converters as _unregister_converters
  File "h5py/_conv.pyx", line 1, in init h5py._conv
  File "h5py/h5r.pyx", line 1, in init h5py.h5r
  File "h5py/h5p.pyx", line 1, in init h5py.h5p
  File "h5py/h5t.pyx", line 289, in init h5py.h5t
  File "h5py/h5t.pyx", line 281, in h5py.h5t._get_available_ftypes
ValueError: chr() arg not in range(0x110000)

It looks like h5py built in the Python 3.14 COPR at one point (the above traceback comes from python3-h5py-3.12.1-4.fc42.x86_64 package in the COPR), but more recent builds have been failing with the error reported in bug 2339470. See that bug for more details on COPR testing.

However, since h5py built at least once in the COPR (but isn‘t usable), dependent packages are starting to get Python 3.14 bug reports because they crash when h5py fails to import. I’ve opened this bug to track the issue and so those packages have something to block.

Reproducible: Always
Comment 1 Ben Beasley 2025-03-14 12:54:15 UTC 
This appears to be fixed in the latest build, https://copr.fedorainfracloud.org/coprs/g/python/python3.14/build/8736441/.