ImportError: cannot import name 'tarfile' from 'backports'

[efranzmann]

Describe the bug
I'm using astroquery with the jplhorizons module which uses keyring as a dependency. I had a student do a fresh install, and she's getting an error that traces back to keyring:

ImportError: cannot import name 'tarfile' from 'backports' (/opt/conda/lib/python3.11/site-packages/backports/__init__.py)

As an experiment I upgraded to the most recent version of keyring and am now seeing the error. Downgrading to keyring 24.3 (which is the version I had previously) fixes the issue.

backports.tarfile downloaded when I installed 25.1, if I'm interpreting things correctly the issue is that it doesn't seem to be finding it.

To Reproduce
Steps to reproduce the behavior:

1. pip install -U --user --pre astroquery
2. pip install -U --user keyring
3. in python: from astroquery.jplhorizons import Horizons

Expected behavior
Module imports and works (as with keyring 24.3)

Environment
Linux of some kind; this is on a JupyterHub run by a 3rd party. Python 3.11.6

$ pip list | grep keyring
keyring                       25.1.0
...
$ keyring --list-backends
Traceback (most recent call last):
  File "/home/jupyter/.local/bin/./keyring", line 5, in <module>
    from keyring.cli import main
  File "/home/jupyter/.local/lib/python3.11/site-packages/keyring/__init__.py", line 1, in <module>
    from .core import (
  File "/home/jupyter/.local/lib/python3.11/site-packages/keyring/core.py", line 11, in <module>
    from . import backend, credentials
  File "/home/jupyter/.local/lib/python3.11/site-packages/keyring/backend.py", line 14, in <module>
    from jaraco.context import ExceptionTrap
  File "/home/jupyter/.local/lib/python3.11/site-packages/jaraco/context.py", line 17, in <module>
    from backports import tarfile
ImportError: cannot import name 'tarfile' from 'backports' (/opt/conda/lib/python3.11/site-packages/backports/__init__.py)

Additional context
Add any other context about the problem here.

[jaraco]

I took a quick look at running the tests on Python 3.11 and they pass on my machine. There may be something more insidious going on on your side. Aha! I think I see the problem in site-packages/backports/__init__.py. The presence of that file indicates that there's another backports module masking the presence of backports.tarfile. Oh, right, because something is installed system-wide that's using the pkgutil-style namespace package, but backports.tarfile is installed in the user path and uses PEP 420 native namespace packages. Root of the issue is at brandon-rhodes/backports#1. I need to revisit that.

Can you identify what other backports you have installed by ls /opt/conda/lib/python3.11/site-packages/backports? Thanks.

[efranzmann]

Thanks for your reply! Result of the command:

$ ls /opt/conda/lib/python3.11/site-packages/backports 
functools_lru_cache.py  __init__.py  __pycache__

[jaraco]

I've confirmed that functools_lru_cache does in fact still use pkgutil style packages, so probably backports.tarfile should do the same. I'll transfer the issue there.

[alesimattia]

I've confirmed that functools_lru_cache does in fact still use pkgutil style packages, so probably backports.tarfile should do the same. I'll transfer the issue there.

Hi, I second the question since I have the same issue and have not resolved.
Could you tell how to "do the same" please?

[jaraco]

See the linked commit 76e9454.

Note that Setuptools 71 recently introduced a bug (pypa/setuptools#4476) that produced this error message, but was unrelated to how any backports.* package was organized.

[alesimattia]

Thank you