fix(vortex): reject columns the writer cannot convert instead of panicking

crates/paimon/src/arrow/format/vortex.rs

@@ -444,6 +444,7 @@ pub(crate) struct VortexFormatWriter {
 
 impl VortexFormatWriter {
     pub(crate) async fn new(output: &OutputFile, schema: SchemaRef) -> crate::Result<Self> {
+        validate_vortex_schema(&schema)?;
         let dtype = DType::from_arrow(schema);
         let bytes_written = Arc::new(AtomicU64::new(0));
 
@@ -457,6 +458,42 @@ impl VortexFormatWriter {
     }
 }
 
+/// `DType::from_arrow` ends in `unimplemented!` for a type it has no arm for, so screen
+/// the schema first. `Map` is the only such type Paimon builds — it is what
+/// `paimon_type_to_arrow` emits for both `MAP` and `MULTISET` — and it can sit at any
+/// depth, so the walk descends the same containers `DType::from_arrow` does.
+fn validate_vortex_schema(schema: &SchemaRef) -> crate::Result<()> {
+    for field in schema.fields() {
+        if contains_unconvertible_type(field.data_type()) {
+            return Err(Error::Unsupported {
+                message: format!(
+                    ".vortex writer does not support column '{}' with type {:?}",
+                    field.name(),
+                    field.data_type()
+                ),
+            });
+        }
+    }
+    Ok(())
+}
+
+fn contains_unconvertible_type(data_type: &ArrowDataType) -> bool {
+    match data_type {
+        ArrowDataType::Map(..) => true,
+        ArrowDataType::List(field)
+        | ArrowDataType::LargeList(field)
+        | ArrowDataType::ListView(field)
+        | ArrowDataType::LargeListView(field)
+        | ArrowDataType::FixedSizeList(field, _)
+        | ArrowDataType::RunEndEncoded(_, field) => contains_unconvertible_type(field.data_type()),
+        ArrowDataType::Struct(fields) => fields
+            .iter()
+            .any(|field| contains_unconvertible_type(field.data_type())),
+        ArrowDataType::Dictionary(_, value_type) => contains_unconvertible_type(value_type),
+        _ => false,
+    }
+}
+
 #[async_trait]
 impl FormatFileWriter for VortexFormatWriter {
     async fn write(&mut self, batch: &RecordBatch) -> crate::Result<()> {
@@ -1392,4 +1429,104 @@ mod tests {
         }
         total_rows
     }
+
+    #[tokio::test]
+    async fn test_vortex_writer_rejects_a_map_column() {
+        use crate::arrow::build_target_arrow_schema;
+        use crate::spec::{DataField, DataType, IntType, MapType, VarCharType};
+
+        let fields = vec![
+            DataField::new(0, "id".to_string(), DataType::Int(IntType::new())),
+            DataField::new(
+                1,
+                "tags".to_string(),
+                DataType::Map(MapType::new(
+                    DataType::VarChar(VarCharType::string_type()),
+                    DataType::Int(IntType::new()),
+                )),
+            ),
+        ];
+        let schema = build_target_arrow_schema(&fields).unwrap();
+
+        let file_io = FileIOBuilder::new("memory").build().unwrap();
+        let output = file_io.new_output("memory:/reject_map.vortex").unwrap();
+
+        let err = match VortexFormatWriter::new(&output, schema).await {
+            Ok(_) => panic!("the vortex writer cannot convert a Map column"),
+            Err(err) => err,
+        };
+        let Error::Unsupported { message } = err else {
+            panic!("expected Unsupported, got {err:?}");
+        };
+        assert!(message.contains("'tags'"), "message: {message}");
+        assert!(message.contains("Map"), "message: {message}");
+    }
+
+    #[tokio::test]
+    async fn test_vortex_writer_rejects_a_multiset_nested_in_a_row() {
+        use crate::arrow::build_target_arrow_schema;
+        use crate::spec::{DataField, DataType, IntType, MultisetType, RowType, VarCharType};
+
+        let fields = vec![DataField::new(
+            0,
+            "nested".to_string(),
+            DataType::Row(RowType::new(vec![
+                DataField::new(1, "n".to_string(), DataType::Int(IntType::new())),
+                DataField::new(
+                    2,
+                    "m".to_string(),
+                    DataType::Multiset(MultisetType::new(DataType::VarChar(
+                        VarCharType::string_type(),
+                    ))),
+                ),
+            ])),
+        )];
+        let schema = build_target_arrow_schema(&fields).unwrap();
+
+        let file_io = FileIOBuilder::new("memory").build().unwrap();
+        let output = file_io
+            .new_output("memory:/reject_nested_multiset.vortex")
+            .unwrap();
+
+        let err = match VortexFormatWriter::new(&output, schema).await {
+            Ok(_) => panic!("a nested Multiset is just as unconvertible as a top-level Map"),
+            Err(err) => err,
+        };
+        let Error::Unsupported { message } = err else {
+            panic!("expected Unsupported, got {err:?}");
+        };
+        assert!(message.contains("'nested'"), "message: {message}");
+        assert!(message.contains("Map"), "message: {message}");
+    }
+
+    /// Positive control: a nested ROW of primitives must still be accepted, so the walk
+    /// cannot be satisfied by a blanket `Struct(..) => true`.
+    #[tokio::test]
+    async fn test_vortex_writer_accepts_a_nested_row_of_primitives() {
+        use crate::arrow::build_target_arrow_schema;
+        use crate::spec::{DataField, DataType, IntType, RowType, VarCharType};
+
+        let fields = vec![DataField::new(
+            0,
+            "nested".to_string(),
+            DataType::Row(RowType::new(vec![
+                DataField::new(1, "n".to_string(), DataType::Int(IntType::new())),
+                DataField::new(
+                    2,
+                    "s".to_string(),
+                    DataType::VarChar(VarCharType::string_type()),
+                ),
+            ])),
+        )];
+        let schema = build_target_arrow_schema(&fields).unwrap();
+
+        let file_io = FileIOBuilder::new("memory").build().unwrap();
+        let output = file_io
+            .new_output("memory:/accept_nested_row.vortex")
+            .unwrap();
+
+        VortexFormatWriter::new(&output, schema)
+            .await
+            .expect("a nested ROW of primitives is convertible");
+    }
 }