Add RecordBatch::schema_ref (#5474)

* Add RecordBatch::schema_ref

* Fix Clippy errors

---------

Co-authored-by: Clide Stefani <[email protected]>

arrow-array/src/record_batch.rs

@@ -236,6 +236,11 @@ impl RecordBatch {
         self.schema.clone()
     }
 
+    /// Returns a reference to the [`Schema`] of the record batch.
+    pub fn schema_ref(&self) -> &SchemaRef {
+        &self.schema
+    }
+
     /// Projects the schema onto the specified columns
     pub fn project(&self, indices: &[usize]) -> Result<RecordBatch, ArrowError> {
         let projected_schema = self.schema.project(indices)?;

arrow-flight/examples/flight_sql_server.rs

@@ -193,9 +193,9 @@ impl FlightSqlService for FlightSqlServiceImpl {
     ) -> Result<Response<<Self as FlightService>::DoGetStream>, Status> {
         self.check_token(&request)?;
         let batch = Self::fake_result().map_err(|e| status!("Could not fake a result", e))?;
-        let schema = batch.schema();
-        let batches = vec![batch];
-        let flight_data = batches_to_flight_data(schema.as_ref(), batches)
+        let schema = batch.schema_ref();
+        let batches = vec![batch.clone()];
+        let flight_data = batches_to_flight_data(schema, batches)
             .map_err(|e| status!("Could not convert batches", e))?
             .into_iter()
             .map(Ok);
@@ -641,10 +641,10 @@ impl FlightSqlService for FlightSqlServiceImpl {
         request: Request<Action>,
     ) -> Result<ActionCreatePreparedStatementResult, Status> {
         self.check_token(&request)?;
-        let schema = Self::fake_result()
-            .map_err(|e| status!("Error getting result schema", e))?
-            .schema();
-        let message = SchemaAsIpc::new(&schema, &IpcWriteOptions::default())
+        let record_batch =
+            Self::fake_result().map_err(|e| status!("Error getting result schema", e))?;
+        let schema = record_batch.schema_ref();
+        let message = SchemaAsIpc::new(schema, &IpcWriteOptions::default())
             .try_into()
             .map_err(|e| status!("Unable to serialize schema", e))?;
         let IpcMessage(schema_bytes) = message;

arrow-flight/src/encode.rs

@@ -320,7 +320,7 @@ impl FlightDataEncoder {
         let schema = match &self.schema {
             Some(schema) => schema.clone(),
             // encode the schema if this is the first time we have seen it
-            None => self.encode_schema(&batch.schema()),
+            None => self.encode_schema(batch.schema_ref()),
         };
 
         // encode the batch
@@ -565,12 +565,12 @@ mod tests {
 
         let batch = RecordBatch::try_from_iter(vec![("a", Arc::new(c1) as ArrayRef)])
             .expect("cannot create record batch");
-        let schema = batch.schema();
+        let schema = batch.schema_ref();
 
         let (_, baseline_flight_batch) = make_flight_data(&batch, &options);
 
         let big_batch = batch.slice(0, batch.num_rows() - 1);
-        let optimized_big_batch = prepare_batch_for_flight(&big_batch, Arc::clone(&schema), false)
+        let optimized_big_batch = prepare_batch_for_flight(&big_batch, Arc::clone(schema), false)
             .expect("failed to optimize");
         let (_, optimized_big_flight_batch) = make_flight_data(&optimized_big_batch, &options);
 
@@ -581,7 +581,7 @@ mod tests {
 
         let small_batch = batch.slice(0, 1);
         let optimized_small_batch =
-            prepare_batch_for_flight(&small_batch, Arc::clone(&schema), false)
+            prepare_batch_for_flight(&small_batch, Arc::clone(schema), false)
                 .expect("failed to optimize");
         let (_, optimized_small_flight_batch) = make_flight_data(&optimized_small_batch, &options);
 

arrow-flight/tests/encode_decode.rs

@@ -465,7 +465,7 @@ async fn roundtrip(input: Vec<RecordBatch>) {
 /// When <https://github.com/apache/arrow-rs/issues/3389> is resolved,
 /// it should be possible to use `roundtrip`
 async fn roundtrip_dictionary(input: Vec<RecordBatch>) {
-    let schema = Arc::new(prepare_schema_for_flight(&input[0].schema()));
+    let schema = Arc::new(prepare_schema_for_flight(input[0].schema_ref()));
     let expected_output: Vec<_> = input
         .iter()
         .map(|batch| prepare_batch_for_flight(batch, schema.clone()).unwrap())

arrow-flight/tests/flight_sql_client_cli.rs

@@ -189,7 +189,7 @@ impl FlightSqlServiceImpl {
         let batch = Self::fake_result()?;
 
         Ok(FlightInfo::new()
-            .try_with_schema(&batch.schema())
+            .try_with_schema(batch.schema_ref())
             .expect("encoding schema")
             .with_endpoint(
                 FlightEndpoint::new().with_ticket(Ticket::new(
@@ -245,9 +245,9 @@ impl FlightSqlService for FlightSqlServiceImpl {
             "part_2" => batch.slice(2, 1),
             ticket => panic!("Invalid ticket: {ticket:?}"),
         };
-        let schema = batch.schema();
-        let batches = vec![batch];
-        let flight_data = batches_to_flight_data(schema.as_ref(), batches)
+        let schema = batch.schema_ref();
+        let batches = vec![batch.clone()];
+        let flight_data = batches_to_flight_data(schema, batches)
             .unwrap()
             .into_iter()
             .map(Ok);

arrow-ipc/src/reader.rs

@@ -1429,7 +1429,7 @@ mod tests {
 
     fn roundtrip_ipc(rb: &RecordBatch) -> RecordBatch {
         let mut buf = Vec::new();
-        let mut writer = crate::writer::FileWriter::try_new(&mut buf, &rb.schema()).unwrap();
+        let mut writer = crate::writer::FileWriter::try_new(&mut buf, rb.schema_ref()).unwrap();
         writer.write(rb).unwrap();
         writer.finish().unwrap();
         drop(writer);
@@ -1440,7 +1440,7 @@ mod tests {
 
     fn roundtrip_ipc_stream(rb: &RecordBatch) -> RecordBatch {
         let mut buf = Vec::new();
-        let mut writer = crate::writer::StreamWriter::try_new(&mut buf, &rb.schema()).unwrap();
+        let mut writer = crate::writer::StreamWriter::try_new(&mut buf, rb.schema_ref()).unwrap();
         writer.write(rb).unwrap();
         writer.finish().unwrap();
         drop(writer);
@@ -1815,7 +1815,7 @@ mod tests {
         let batch = RecordBatch::new_empty(schema);
 
         let mut buf = Vec::new();
-        let mut writer = crate::writer::FileWriter::try_new(&mut buf, &batch.schema()).unwrap();
+        let mut writer = crate::writer::FileWriter::try_new(&mut buf, batch.schema_ref()).unwrap();
         writer.write(&batch).unwrap();
         writer.finish().unwrap();
         drop(writer);
@@ -1842,7 +1842,7 @@ mod tests {
         let batch = RecordBatch::new_empty(schema);
 
         let mut buf = Vec::new();
-        let mut writer = crate::writer::FileWriter::try_new(&mut buf, &batch.schema()).unwrap();
+        let mut writer = crate::writer::FileWriter::try_new(&mut buf, batch.schema_ref()).unwrap();
         writer.write(&batch).unwrap();
         writer.finish().unwrap();
         drop(writer);

arrow-ipc/src/writer.rs

@@ -1436,7 +1436,7 @@ mod tests {
     use super::*;
 
     fn serialize_file(rb: &RecordBatch) -> Vec<u8> {
-        let mut writer = FileWriter::try_new(vec![], &rb.schema()).unwrap();
+        let mut writer = FileWriter::try_new(vec![], rb.schema_ref()).unwrap();
         writer.write(rb).unwrap();
         writer.finish().unwrap();
         writer.into_inner().unwrap()
@@ -1448,7 +1448,7 @@ mod tests {
     }
 
     fn serialize_stream(record: &RecordBatch) -> Vec<u8> {
-        let mut stream_writer = StreamWriter::try_new(vec![], &record.schema()).unwrap();
+        let mut stream_writer = StreamWriter::try_new(vec![], record.schema_ref()).unwrap();
         stream_writer.write(record).unwrap();
         stream_writer.finish().unwrap();
         stream_writer.into_inner().unwrap()
@@ -1982,7 +1982,7 @@ mod tests {
         )
         .expect("new batch");
 
-        let mut writer = StreamWriter::try_new(vec![], &batch.schema()).expect("new writer");
+        let mut writer = StreamWriter::try_new(vec![], batch.schema_ref()).expect("new writer");
         writer.write(&batch).expect("write");
         let outbuf = writer.into_inner().expect("inner");
 

parquet/src/arrow/arrow_reader/mod.rs

@@ -3082,7 +3082,7 @@ mod tests {
                     .unwrap();
 
                 let batches = reader.collect::<Result<Vec<_>, _>>().unwrap();
-                let actual = concat_batches(&batch.schema(), &batches).unwrap();
+                let actual = concat_batches(batch.schema_ref(), &batches).unwrap();
                 assert_eq!(actual.num_rows(), selection.row_count());
 
                 let mut batch_offset = 0;