issue_comments

Yep, I hope I'll have time for more to come :)

Thanks @OriolAbril . I see this is your first PR. Thanks!

Thanks @OriolAbril . This looks good to me. Can you add a note under enhancements in whats-new.rst?

Fixed tests. Now single index coordinates will keep their attributes when converted to non indexing coordinates.

I think changes in code would also make multi index keep their attributes, but I don't think multiindex can have attributes so it does not make any difference. I was wondering is this would be enough to close the original issue or if there is extra work to be done with multiindex.

Modified test sounds good to me. I'll open another issue.

Thanks @dcherian! If there is anything I can do to help please say so. I don't really know where to start searching for this new error but I can run some tests or look into it if given some pointers. Whatever means less work for you.

Regarding current test, I can modify it so it does not trigger the bug and open an issue for this second bug. Is this ok or do yo prefer to tackle both in this PR?

Nice job @OriolAbril! you seem to have found a bug where renaming doesn't create an IndexVariable when necessary. I will look into this.

``` ___ TestDataArray.testreset_index_keep_attrs _____

self = <xarray.tests.test_dataarray.TestDataArray object at 0x7f266d36c4d0>

def test_reset_index_keep_attrs(self):
    coord_1 = xr.DataArray([1, 2], dims=["coord_1"], attrs={"attrs": True})
    da = xr.DataArray([1, 0], [coord_1])
    obj = da.reset_index("coord_1").rename({"coord_1_": "coord_1"})

  assert_identical(da, obj)

xarray/tests/test_dataarray.py:1837:

xarray/testing.py:267: in _assert_internal_invariants _assert_dataarray_invariants(xarray_obj)

da = <xarray.DataArray (coord_1: 2)> array([1, 0]) Coordinates: * coord_1 (coord_1) int64 1 2

def _assert_dataarray_invariants(da: DataArray):
    assert isinstance(da._variable, Variable), da._variable
    _assert_variable_invariants(da._variable)

    assert isinstance(da._coords, dict), da._coords
    assert all(isinstance(v, Variable) for v in da._coords.values()), da._coords
    assert all(set(v.dims) <= set(da.dims) for v in da._coords.values()), (
        da.dims,
        {k: v.dims for k, v in da._coords.items()},
    )
    assert all(
        isinstance(v, IndexVariable) for (k, v) in da._coords.items() if v.dims == (k,)

  ), {k: type(v) for k, v in da._coords.items()}

E AssertionError: {'coord_1': <class 'xarray.core.variable.Variable'>}

```