Verbose error handling for non-valid duckarrays

[Illviljan]

It is rather annoying trying to figure out why some arrays aren't valid duckarrays. This PR logs the missing attributes instead of just saying it isn't valid.

Example:

    def test_duck_array_class_pd_index(self) -> None:
        import pandas as pd

        a: duckarray[Any, Any] = pd.Index([])
        check_duck_array_typevar(a)

FAILED xarray/tests/test_namedarray.py::TestNamedArray::test_pd_index_duckarray - TypeError: a (<class 'pandas.core.indexes.base.Index'>) is not a valid _arrayfunction or _arrayapi. Missing following attrs:
_arrayfunction - {'imag', '__array_function__', 'real'}
_arrayapi - {'__array_namespace__'}

Further reading: python/cpython#104873

[Illviljan]

The mypy CI is uninstalling numpy 2.0.1 and installing numpy 1.26 instead for some reason, anyone know why?

Run python -m mypy --install-types --non-interactive --cobertura-xml-report mypy_report xarray/
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  Downloading pandas_stubs-2.2.2.240805-py3-none-any.whl.metadata (10 kB)
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Requirement already satisfied: urllib3>=2 in /home/runner/micromamba/envs/xarray-tests/lib/python3.11/site-packages (from types-requests) (2.2.2)
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Downloading numpy-1.26.4-cp311-cp311-manylinux_2_17_x86_64.manylinux2014_x86_64.whl (18.3 MB)
25l   ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━ 0.0/18.3 MB ? eta -:--:--
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25hDownloading types_docutils-0.21.0.20240724-py3-none-any.whl (27 kB)
Downloading types_setuptools-71.1.0.20240726-py3-none-any.whl (64 kB)
Installing collected packages: types-tqdm, types-setuptools, types-requests, types-PyYAML, types-pytz, types-python-dateutil, types-psutil, types-docutils, types-colorama, numpy, types-Pygments, types-cffi, pandas-stubs
  Attempting uninstall: numpy
    Found existing installation: numpy 2.0.1
    Uninstalling numpy-2.0.1:
      Successfully uninstalled numpy-2.0.1
Successfully installed numpy-1.26.4 pandas-stubs-2.2.2.240805 types-PyYAML-6.0.12.20240724 types-Pygments-2.18.0.20240506 types-cffi-1.16.0.20240331 types-colorama-0.4.15.20240311 types-docutils-0.21.0.20240724 types-psutil-6.0.0.20240621 types-python-dateutil-2.9.0.20240316 types-pytz-2024.1.0.20240417 types-requests-2.32.0.20240712 types-setuptools-71.1.0.20240726 types-tqdm-4.66.0.20240417

[Illviljan]

pandas-stubs forces numpy <2.0.0 now: pandas-dev/pandas-stubs#943
I'm not sure how to deal with this.

[max-sixty]

Very nice!