bodduv opened a new issue, #692: URL: https://github.com/apache/arrow-java/issues/692
### Describe the bug, including details regarding any error messages, version, and platform. In the main branch, `DecimalVector` and `Decimal256Vector` are losing nullability information during a zero-copy transfer. It currently **forces** a nullable `FieldType` onto the "to" `ValueVector`. The deficiency in the code is in `DecimalVector.TransferImpl` class when trying to get a transfer `getTransferPair(String, BufferAllocator)` creating a `DecimalVector` with a nullable `FieldType` (although the "from" ValueVector's FieldType is non-nullable): https://github.com/apache/arrow-java/blob/48a20ba91605ebb44df845671782acd8f869bd4b/vector/src/main/java/org/apache/arrow/vector/DecimalVector.java#L563-L569 Note that all the other (at least the primitive) `ValueVector`s are transferred without losing nullability information by using the "from" `ValueVector`'s field. E.g.: https://github.com/apache/arrow-java/blob/48a20ba91605ebb44df845671782acd8f869bd4b/vector/src/main/java/org/apache/arrow/vector/BigIntVector.java#L319-L324 --- To **reproduce** the issue: add the following test in `src/test/java/org/apache/arrow/vector/TestDecimalVector.java` to see it fail. ```java @Test public void testGetTransferPairWithoutFieldNonNullable() { final FieldType decimalNonNullableType = new FieldType(false, new ArrowType.Decimal(10, scale), null); final DecimalVector fromVector = new DecimalVector("decimal", decimalNonNullableType, allocator); final TransferPair transferPair = fromVector.getTransferPair(fromVector.getField().getName(), allocator); final DecimalVector toVector = (DecimalVector) transferPair.getTo(); // These asserts fail assertSame(fromVector.getField().isNullable(), toVector.getField().isNullable()); assertSame(fromVector.getField().getFieldType(), toVector.getField().getFieldType()); } ``` -- 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: issues-unsubscr...@arrow.apache.org.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org
