issue_comments: 602044048

Hmm...the upstream-dev CI environment does not seem to be using the latest version of pandas. The failures don't seem to reflect the fact that https://github.com/pandas-dev/pandas/pull/32684 was merged.

Testing locally with pandas master, I'm actually getting some new failures related to CFTimeIndex, e.g.: ``` ______ testconcat_cftimeindex[proleptic_gregorian] ________

date_type = <class 'cftime._cftime.DatetimeProlepticGregorian'>

@requires_cftime
def test_concat_cftimeindex(date_type):
    da1 = xr.DataArray(

      [1.0, 2.0], coords=[[date_type(1, 1, 1), date_type(1, 2, 1)]], dims=["time"]
    )

test_cftimeindex.py:670:

../core/dataarray.py:344: in init coords, dims = _infer_coords_and_dims(data.shape, coords, dims) ../core/dataarray.py:165: in _infer_coords_and_dims assert_unique_multiindex_level_names(new_coords) ../core/variable.py:2390: in assert_unique_multiindex_level_names idx_level_names = var.to_index_variable().level_names ../core/variable.py:2252: in level_names index = self.to_index() ../core/variable.py:2244: in to_index index = index.set_names(self.name) ../../../pandas/pandas/core/indexes/base.py:1291: in set_names idx = self._shallow_copy()

self = CFTimeIndex([0001-01-01 00:00:00, 0001-02-01 00:00:00], dtype='object'), values = None, name = None

def _shallow_copy(self, values=None, name: Label = no_default):
    """
    Create a new Index with the same class as the caller, don't copy the
    data, use the same object attributes with passed in attributes taking
    precedence.

    *this is an internal non-public method*

    Parameters
    ----------
    values : the values to create the new Index, optional
    name : Label, defaults to self.name
    """
    name = self.name if name is no_default else name

  cache = self._cache.copy() if values is None else {}

E AttributeError: 'CFTimeIndex' object has no attribute '_cache'

../../../pandas/pandas/core/indexes/base.py:500: AttributeError ```