ewoodbury commented on code in PR #3255:
URL: https://github.com/apache/iceberg-rust/pull/3255#discussion_r4235431634
##########
crates/iceberg/src/arrow/record_batch_transformer.rs:
##########
@@ -193,6 +195,284 @@ pub(crate) enum ColumnSource {
// post-processing step by using the projection mask.
}
+/// Reconciles a source array to the target type by matching nested fields on
+/// field id rather than position, mirroring iceberg-java's nested readers.
+///
+/// The plan is resolved once per file, when the `BatchTransform` is built, so
+/// applying it per batch is just index lookups and array assembly.
+#[derive(Debug)]
+pub(crate) enum PromotePlan {
+ PassThrough,
+ Cast(DataType),
+ Struct {
+ fields: Fields,
+ children: Vec<ChildPlan>,
+ },
+ List {
+ field: FieldRef,
+ element: Box<PromotePlan>,
+ },
+ Map {
+ field: FieldRef,
+ entry_fields: Fields,
+ entries: Vec<ChildPlan>,
+ sorted: bool,
+ },
+}
+
+#[derive(Debug)]
+pub(crate) enum ChildPlan {
+ FromSource {
+ source_index: usize,
+ plan: PromotePlan,
+ },
+ Add {
+ target_type: DataType,
+ value: Option<PrimitiveLiteral>,
+ },
+}
+
+impl PromotePlan {
+ fn build(
+ source: &DataType,
+ target: &DataType,
+ snapshot_schema: &IcebergSchema,
+ constant_fields: &HashMap<i32, ColumnConstant>,
+ ) -> Result<Self> {
+ if source == target {
+ return Ok(PromotePlan::PassThrough);
+ }
+ match (source, target) {
+ (DataType::Struct(source_fields), DataType::Struct(target_fields))
=> {
+ Ok(PromotePlan::Struct {
+ children: Self::build_struct_children(
+ source_fields,
+ target_fields,
+ snapshot_schema,
+ constant_fields,
+ )?,
+ fields: target_fields.clone(),
+ })
+ }
+ // A file's Arrow schema hint can give either offset width;
`apply` converts it.
+ // Table schemas are always `List`
(`ToArrowSchemaConverter::list`).
+ (
+ DataType::List(source_field) |
DataType::LargeList(source_field),
+ DataType::List(target_field),
+ ) => Ok(PromotePlan::List {
+ element: Box::new(Self::build(
+ source_field.data_type(),
+ target_field.data_type(),
+ snapshot_schema,
+ constant_fields,
+ )?),
+ field: target_field.clone(),
+ }),
+ (DataType::Map(source_entries, _), DataType::Map(target_entries,
sorted)) => {
+ match (source_entries.data_type(), target_entries.data_type())
{
+ (DataType::Struct(source_fields),
DataType::Struct(target_fields)) => {
+ Ok(PromotePlan::Map {
+ entries: Self::build_struct_children(
+ source_fields,
+ target_fields,
+ snapshot_schema,
+ constant_fields,
+ )?,
+ entry_fields: target_fields.clone(),
+ field: target_entries.clone(),
+ sorted: *sorted,
+ })
+ }
+ _ => Err(Error::new(
+ ErrorKind::Unexpected,
+ format!(
+ "expected struct-typed map entries, got
{source_entries:?} and {target_entries:?}"
Review Comment:
Makes sense, switched the map-entries arm to `invalid_data!` and added a
case for it. I kept `promote_err` as `Unexpected`: it only fires if a batch's
column doesn't match the schema the plan was built from (which is a caller bug
rather than bad file data).
--
This is an automated message from the Apache Git Service.
To respond to the message, please log on to GitHub and use the
URL above to go to the specific comment.
To unsubscribe, e-mail: [email protected]
For queries about this service, please contact Infrastructure at:
[email protected]
---------------------------------------------------------------------
To unsubscribe, e-mail: [email protected]
For additional commands, e-mail: [email protected]
