gruuya commented on PR #7188:
URL: https://github.com/apache/arrow-rs/pull/7188#issuecomment-2681061340
I've found a work-around to reconstruct an empty batch that uses
`FlightRecordBatchStream` directly
```rust
#[tokio::test]
async fn test_empty_batch_round_trip() {
let schema = Schema::new(vec![Field::new("data", DataType::Int32,
false)]);
let empty_batch = RecordBatch::new_empty(Arc::new(schema));
let stream =
FlightDataEncoderBuilder::new().build(futures::stream::iter(vec![Ok(empty_batch.clone())]));
let mut stream = FlightRecordBatchStream::new_from_flight_data(stream);
let mut data: Vec<RecordBatch> = vec![];
while let Ok(Some(batch)) = stream.try_next().await {
data.push(batch);
}
// If no batches were decoded but a schema was, construct an empty batch
with that schema
if data.is_empty() && let Some(schema) = stream.schema() {
data = vec![RecordBatch::new_empty(schema.clone())];
}
assert_eq!(data, vec![empty_batch]);
}
```
In this way the stream is not consumed after extracting batches, so I can
check if a schema was received, and if so construct an empty batch with that
schema. Closing, thanks!
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