[C++][Parquet] Fix schema conversion from two-level encoding nested list

[wgtmac]

Describe the bug, including details regarding any error messages, version, and platform.

I have seen an issue when reading a Parquet file created by Hudi. There is a nesting list as below:

  optional group a (LIST) {
    repeated group array (LIST) {
      repeated int32 array;
    }
  }

The C++ parquet reader infers its schema as array<struct<array:array<int>>>. The root cause is here:

arrow/cpp/src/parquet/arrow/schema.cc

Lines 657 to 663 in 12dddfc

	// We distinguish the special case that we have
	//
	// required/optional group name=whatever {
	// repeated group name=array or $SOMETHING_tuple {
	// required/optional TYPE item;
	// }
	// }

I think we need to regard them as a nesting two-level list, meaning that the correct interpretation is array<array<int>>.

Component(s)

C++, Parquet

[mapleFU]

array<array<int>>?