See Issue #145 . When the outer key type is Empty, we use a single ref counted column of type Empty to prevent unnecessary allocations, but when the ungroup outer key type is not Empty, we currently do not allocate the key column for the output batch in the ungroup pipe, leading to a null reference.
See Issue #145 . When the outer key type is Empty, we use a single ref counted column of type Empty to prevent unnecessary allocations, but when the ungroup outer key type is not Empty, we currently do not allocate the key column for the output batch in the ungroup pipe, leading to a null reference.