Force block partitions materialization

modin/core/execution/ray/implementations/pandas_on_ray/partitioning/virtual_partition.py

@@ -88,7 +88,7 @@ def __init__(
  if not isinstance(data, Collection) or len(data) == 1:
  if not isinstance(data, Collection):
  data = [data]
- self._set_data_ref(data[0]._data_ref)
+ self._set_data_ref(data[0]._data)
  self._num_splits = 1
  self._list_of_block_partitions = data
  return
@@ -119,6 +119,7 @@ def __init__(
  # TODO: We have a subset of the same frame here and can just get a single chunk
  # from the original frame instead of concatenating all these chunks.
 
+ data = [part._data for part in self._list_of_block_partitions]
  self._set_data_ref(self._concat(refs))
 
  def _set_data_ref(
@@ -165,16 +166,16 @@ def apply(
  if other_axis_partition is not None:
  if isinstance(other_axis_partition, Collection):
  if len(other_axis_partition) == 1:
- other_part = other_axis_partition[0]._data_ref
+ other_part = other_axis_partition[0]._data
  else:
  concat_fn = (
  PandasOnRayDataframeColumnPartition
  if self.axis
  else PandasOnRayDataframeRowPartition
  )._concat
- other_part = concat_fn([p._data_ref for p in other_axis_partition])
+ other_part = concat_fn([p._data for p in other_axis_partition])
  else:
- other_part = other_axis_partition._data_ref
+ other_part = other_axis_partition._data
  args = [other_part] + list(args)
 
  de = self._apply(func, args, kwargs)