GH-43320: [Java] fix for SchemaChangeRuntimeException transferring em…

…pty FixedSizeListVector (#43321) ### What changes are included in this PR? When we create a FSLV through TransferImpl, we check to see if the source's element vector is a ZeroVector and, if not, we don't call addOrGetVector. ### Are these changes tested? Yep - see TestFixedSizeListVector ### Are there any user-facing changes? No * GitHub Issue: #43320 Authored-by: James Henderson <[email protected]> Signed-off-by: David Li <[email protected]>
apache · Jul 19, 2024 · bbfb7b9 · bbfb7b9
1 parent 0bae073
commit bbfb7b9
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diff --git a/java/vector/src/main/java/org/apache/arrow/vector/complex/FixedSizeListVector.java b/java/vector/src/main/java/org/apache/arrow/vector/complex/FixedSizeListVector.java
@@ -602,7 +602,9 @@ public TransferImpl(Field field, BufferAllocator allocator, CallBack callBack) {
 
     public TransferImpl(FixedSizeListVector to) {
       this.to = to;
-      to.addOrGetVector(vector.getField().getFieldType());
+      if (!(vector instanceof ZeroVector)) {
+        to.addOrGetVector(vector.getField().getFieldType());
+      }
       dataPair = vector.makeTransferPair(to.vector);
     }
 

diff --git a/java/vector/src/test/java/org/apache/arrow/vector/TestFixedSizeListVector.java b/java/vector/src/test/java/org/apache/arrow/vector/TestFixedSizeListVector.java
@@ -26,6 +26,7 @@
 import java.math.BigDecimal;
 import java.nio.ByteBuffer;
 import java.nio.charset.StandardCharsets;
+import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
 import org.apache.arrow.memory.BufferAllocator;
@@ -243,6 +244,34 @@ public void testTransferPair() {
     }
   }
 
+  @Test
+  public void testTransferEmptyVector() throws Exception {
+    // #43320
+    try (FixedSizeListVector src =
+            new FixedSizeListVector(
+                "src", allocator, FieldType.nullable(new ArrowType.FixedSizeList(2)), null);
+        FixedSizeListVector dest =
+            new FixedSizeListVector(
+                "dest", allocator, FieldType.nullable(new ArrowType.FixedSizeList(2)), null)) {
+      src.makeTransferPair(dest).transfer();
+
+      IntVector els =
+          (IntVector) dest.addOrGetVector(FieldType.nullable(MinorType.INT.getType())).getVector();
+
+      dest.allocateNew();
+      dest.startNewValue(0);
+      els.setSafe(0, 1);
+      els.setSafe(1, 2);
+      dest.setValueCount(1);
+
+      List<Integer> expected = new ArrayList<>(2);
+      expected.add(1);
+      expected.add(2);
+
+      assertEquals(expected, dest.getObject(0));
+    }
+  }
+
   @Test
   public void testConsistentChildName() throws Exception {
     try (FixedSizeListVector listVector =