LazilyOuterIndexedArray doesn't support slicing with slice objects #3022
Description
Code Sample, a copy-pastable example if possible
from xarray.core.indexing import LazilyOuterIndexedArray
import numpy as np
x = LazilyOuterIndexedArray(np.ones((5, 5)))
x[:3]---------------------------------------------------------------------------
AttributeError Traceback (most recent call last)
<ipython-input-4-42bee9beb30a> in <module>
----> 1 x[:3]
~/workspace/xarray/xarray/core/indexing.py in __getitem__(self, indexer)
518 array = LazilyVectorizedIndexedArray(self.array, self.key)
519 return array[indexer]
--> 520 return type(self)(self.array, self._updated_key(indexer))
521
522 def __setitem__(self, key, value):
~/workspace/xarray/xarray/core/indexing.py in _updated_key(self, new_key)
483
484 def _updated_key(self, new_key):
--> 485 iter_new_key = iter(expanded_indexer(new_key.tuple, self.ndim))
486 full_key = []
487 for size, k in zip(self.array.shape, self.key.tuple):
AttributeError: 'slice' object has no attribute 'tuple'Problem description
Dask array meta computations like to run x[:0, :0] on input arrays. This breaks with this class.
This is on master