make unproject_layout do nothing; check report for shape_touched.

src/dask_awkward/lib/optimize.py

@@ -421,7 +421,7 @@ def _necessary_columns(dsk: HighLevelGraph) -> dict[str, list[str]]:
  """Pair layer names with lists of necessary columns."""
  kv = {}
  for name, report in _get_column_reports(dsk).items():
- cols = {_ for _ in report.data_touched if _ is not None}
+ cols = {_ for _ in report.data_touched + report.shape_touched if _ is not None}
  select = []
  for col in sorted(cols):
  if col == name:

src/dask_awkward/lib/unproject_layout.py

@@ -401,6 +401,7 @@ def unproject_layout(form: Form | None, layout: Content) -> Content:
  not appear in the projected layout will be PlaceholderArrays).
 
  """
- if form is None:
- return layout
- return _unproject_layout(form, layout, layout.length, layout.backend)
+ return layout
+ # if form is None:
+ # return layout
+ # return _unproject_layout(form, layout, layout.length, layout.backend)