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Is it related to this? 🤷‍♀️

• memoryview can set an exception in tp_clear python/cpython#77894

Hmm could the failure only happen in Python 3.11.2 + numpy-dev combo?

I cannot reproduce this with Python 3.11.0 from conda and numpy nightly wheel. The log in CI says it is using Python 3.11.2.

Last green devdeps: https://github.com/astropy/astropy/actions/runs/4247771490/jobs/7386198567 (before all the asdf deprecations getting in the way)

Full Python Version: 
3.11.2 (main, Feb  8 2023, 08:38:01) [GCC 11.3.0]

Numpy: 1.25.0.dev0+678.g51ecf8401

Now with this failure: https://github.com/astropy/astropy/actions/runs/4265444197/jobs/7424786551

Full Python Version: 
3.11.2 (main, Feb  8 2023, 08:38:01) [GCC 11.3.0]

Numpy: 1.25.0.dev0+787.g3f142646c

The diff can be seen in https://github.com/numpy/numpy/compare/51ecf8401..3f142646c but that is too many changes. The nightlies appear to be a week apart according to https://anaconda.org/scipy-wheels-nightly/numpy/files .

Almost certainly numpy/numpy#22924 given the "RuntimeError: Internal error, tried to fetch clear function for the user dtype '�' without fields or subarray (legacy support)", which was introduced there...

Our failure looks due to astropy/io/votable/tests/table_test.py, specifically test_binary2_masked_strings, but it does not raise if one just does the one test -- it requires test_no_field_not_empty_table to be run beforehand to cause the problem (all others can be commented out and do not change the result).

Indeed, the latter seems to be the real problem. in a separate ipython session, I get

In [1]: from astropy.io.votable.tests.table_test import test_no_field_not_empty_table

In [2]: test_no_field_not_empty_table()

In [3]:                                                                                                         
Do you really want to exit ([y]/n)? 
Exception ignored in tp_clear of: <class 'astropy.io.votable.tree.VOTableFile'>
Traceback (most recent call last):
  File "/data/mhvk/venv/numpy-dev2/lib/python3.11/site-packages/IPython/core/displayhook.py", line 317, in flush
    gc.collect()
RuntimeError: Internal error, tried to fetch clear function for the user dtype '' without fields or subarray (legacy support).

So, it clearly is something that happens only at clean-up time.

Minimal example to reproduce:

In [1]: from astropy.utils.data import get_pkg_data_filename

In [2]: from astropy.io.votable.table import parse

In [3]: votable = parse(get_pkg_data_filename("data/no_field_not_empty_table.xml", package='astropy.io.votable.t
   ...: ests'))

In [4]:                                                                                                         
Do you really want to exit ([y]/n)? 
Exception ignored in tp_clear of: <class 'astropy.io.votable.tree.VOTableFile'>
RuntimeError: Internal error, tried to fetch clear function for the user dtype '' without fields or subarray (legacy support).

Digging deeper, I think this may be the dtype causing a problem

In [26]: votable.resources[0].tables[0].array
Out[26]: 
masked_recarray(data=[],
                mask=[],
          fill_value=b'???',
               dtype='|V8')

This leads to a pure numpy example - see numpy/numpy#23277

Fixed upstream. CI is green on main now. Thanks, all!

https://github.com/astropy/astropy/actions/runs/4285566401/jobs/7464036187

Great!