issues: 417542619

This is due to setting multi-dimensional attributes being an error, as of the latest netCDF4-Python release: https://github.com/Unidata/netcdf4-python/blob/master/Changelog

E.g., as seen on Appveyor: https://ci.appveyor.com/project/shoyer/xray/builds/22834250/job/9q0ip6i3cchlbkw2 ``` ================================== FAILURES =================================== ___ TestValidateAttrs.test_validating_attrs _____ self = <xarray.tests.test_backends.TestValidateAttrs object at 0x00000096BE5FAFD0> def test_validating_attrs(self): def new_dataset(): return Dataset({'data': ('y', np.arange(10.0))}, {'y': np.arange(10)})

    def new_dataset_and_dataset_attrs():
        ds = new_dataset()
        return ds, ds.attrs

    def new_dataset_and_data_attrs():
        ds = new_dataset()
        return ds, ds.data.attrs

    def new_dataset_and_coord_attrs():
        ds = new_dataset()
        return ds, ds.coords['y'].attrs

    for new_dataset_and_attrs in [new_dataset_and_dataset_attrs,
                                  new_dataset_and_data_attrs,
                                  new_dataset_and_coord_attrs]:
        ds, attrs = new_dataset_and_attrs()

        attrs[123] = 'test'
        with raises_regex(TypeError, 'Invalid name for attr'):
            ds.to_netcdf('test.nc')

        ds, attrs = new_dataset_and_attrs()
        attrs[MiscObject()] = 'test'
        with raises_regex(TypeError, 'Invalid name for attr'):
            ds.to_netcdf('test.nc')

        ds, attrs = new_dataset_and_attrs()
        attrs[''] = 'test'
        with raises_regex(ValueError, 'Invalid name for attr'):
            ds.to_netcdf('test.nc')

        # This one should work
        ds, attrs = new_dataset_and_attrs()
        attrs['test'] = 'test'
        with create_tmp_file() as tmp_file:
            ds.to_netcdf(tmp_file)

        ds, attrs = new_dataset_and_attrs()
        attrs['test'] = {'a': 5}
        with raises_regex(TypeError, 'Invalid value for attr'):
            ds.to_netcdf('test.nc')

        ds, attrs = new_dataset_and_attrs()
        attrs['test'] = MiscObject()
        with raises_regex(TypeError, 'Invalid value for attr'):
            ds.to_netcdf('test.nc')

        ds, attrs = new_dataset_and_attrs()
        attrs['test'] = 5
        with create_tmp_file() as tmp_file:
            ds.to_netcdf(tmp_file)

        ds, attrs = new_dataset_and_attrs()
        attrs['test'] = 3.14
        with create_tmp_file() as tmp_file:
            ds.to_netcdf(tmp_file)

        ds, attrs = new_dataset_and_attrs()
        attrs['test'] = [1, 2, 3, 4]
        with create_tmp_file() as tmp_file:
            ds.to_netcdf(tmp_file)

        ds, attrs = new_dataset_and_attrs()
        attrs['test'] = (1.9, 2.5)
        with create_tmp_file() as tmp_file:
            ds.to_netcdf(tmp_file)

        ds, attrs = new_dataset_and_attrs()
        attrs['test'] = np.arange(5)
        with create_tmp_file() as tmp_file:
            ds.to_netcdf(tmp_file)

        ds, attrs = new_dataset_and_attrs()
        attrs['test'] = np.arange(12).reshape(3, 4)
        with create_tmp_file() as tmp_file:

          ds.to_netcdf(tmp_file)

xarray\tests\test_backends.py:3450:

xarray\core\dataset.py:1323: in to_netcdf compute=compute) xarray\backends\api.py:767: in to_netcdf unlimited_dims=unlimited_dims) xarray\backends\api.py:810: in dump_to_store unlimited_dims=unlimited_dims) xarray\backends\common.py:262: in store self.set_attributes(attributes) xarray\backends\common.py:278: in set_attributes self.set_attribute(k, v) xarray\backends\netCDF4_.py:418: in set_attribute set_nc_attribute(self.ds, key, value) xarray\backends\netCDF4.py:294: in _set_nc_attribute obj.setncattr(key, value) netCDF4_netCDF4.pyx:2781: in netCDF4._netCDF4.Dataset.setncattr ???

??? E ValueError: multi-dimensional array attributes not supported netCDF4_netCDF4.pyx:1514: ValueError ```