Function with_unmapped_partition_columns 

fn with_unmapped_partition_columns(
    table: &TableRef,
    current: &TableRef,
) -> TableRef

Builds a table that keeps the schema of table and reports the partition columns of current as absent from that schema.

A scan’s projection holds indices into the schema it was built on, and Substrait sends that schema with those indices, so a plan cannot move to a changed schema. Reporting the columns as absent keeps distributed planning from relying on any of them.