Fix pylibcudf to_arrow with multiple nested data types

python/pylibcudf/pylibcudf/interop.pyx

@@ -273,10 +273,19 @@ cdef void _release_array(object array_capsule) noexcept:
     free(array)
 
 
+def _maybe_create_nested_column_metadata(Column col):
+    return ColumnMetadata(
+        children_meta=[
+            _maybe_create_nested_column_metadata(child) for child in col.children()
+        ]
+    )
+
+
 def _table_to_schema(Table tbl, metadata):
     if metadata is None:
-        metadata = [ColumnMetadata() for _ in range(len(tbl.columns()))]
-    metadata = [ColumnMetadata(m) if isinstance(m, str) else m for m in metadata]
+        metadata = [_maybe_create_nested_column_metadata(col) for col in tbl.columns()]
+    else:
+        metadata = [ColumnMetadata(m) if isinstance(m, str) else m for m in metadata]
 
     cdef vector[column_metadata] c_metadata
     c_metadata.reserve(len(metadata))

python/pylibcudf/pylibcudf/tests/test_interop.py

@@ -40,6 +40,28 @@ def test_struct_dtype_roundtrip():
     assert arrow_type == struct_type
 
 
+def test_table_with_nested_dtype_to_arrow():
+    pa_array = pa.array([[{"": 1}]])
+    plc_table = plc.Table([plc.interop.from_arrow(pa_array)])
+    result = plc.interop.to_arrow(plc_table)
+    expected_schema = pa.schema(
+        [
+            pa.field(
+                "",
+                pa.list_(
+                    pa.field(
+                        "",
+                        pa.struct([pa.field("", pa.int64(), nullable=False)]),
+                        nullable=False,
+                    )
+                ),
+                nullable=False,
+            )
+        ]
+    )
+    assert result.schema == expected_schema
+
+
 def test_decimal128_roundtrip():
     decimal_type = pa.decimal128(10, 2)
     plc_type = plc.interop.from_arrow(decimal_type)