Fix merge

Author: carlosdelest

server/src/main/java/org/elasticsearch/index/mapper/BlockDocValuesReader.java

@@ -38,6 +38,7 @@
 import java.io.IOException;
 
 import static org.elasticsearch.index.mapper.vectors.DenseVectorFieldMapper.COSINE_MAGNITUDE_FIELD_SUFFIX;
+import static org.elasticsearch.index.mapper.vectors.DenseVectorFieldMapper.ElementType.BYTE;
 
 /**
  * A reader that supports reading doc-values from a Lucene segment in Block fashion.
@@ -540,9 +541,8 @@ public AllReader reader(LeafReaderContext context) throws IOException {
                                 .getNumericDocValues(fieldType.name() + COSINE_MAGNITUDE_FIELD_SUFFIX);
                             return new FloatDenseVectorNormalizedValuesBlockReader(floatVectorValues, dimensions, magnitudeDocValues);
                         }
-                        }
-                        return new FloatDenseVectorValuesBlockReader(floatVectorValues, dimensions);
                     }
+                    return new FloatDenseVectorValuesBlockReader(floatVectorValues, dimensions);
                 }
                 case BYTE -> {
                     ByteVectorValues byteVectorValues = context.reader().getByteVectorValues(fieldName);
@@ -657,7 +657,6 @@ protected void appendDoc(BlockLoader.FloatBuilder builder) throws IOException {
         @Override
         public String toString() {
             return "BlockDocValuesReader.FloatDenseVectorNormalizedValuesBlockReader";
-            return "BlockDocValuesReader.FloatDenseVectorNormalizedValuesBlockReader";
         }
     }
 

x-pack/plugin/esql/src/internalClusterTest/java/org/elasticsearch/xpack/esql/DenseVectorFieldTypeIT.java

@@ -219,13 +219,14 @@ public void setup() throws IOException {
                         default -> throw new IllegalArgumentException("Unexpected element type: " + elementType);
                     }
                 }
-                if (similarity == DenseVectorFieldMapper.VectorSimilarity.DOT_PRODUCT || rarely()) {
+                if ((elementType == ElementType.FLOAT) && (similarity == DenseVectorFieldMapper.VectorSimilarity.DOT_PRODUCT || rarely())) {
                     // Normalize the vector
                     float magnitude = DenseVector.getMagnitude(vector);
-                    switch (elementType) {
-                        case FLOAT -> vector.replaceAll(number -> number.floatValue() / magnitude);
-                        case BYTE -> vector.replaceAll(number -> (byte) (number.byteValue() / magnitude));
-                    }
+                    vector.replaceAll(number -> number.floatValue() / magnitude);
+                }
+                if (vector.stream().allMatch(v -> v.floatValue() == 0.0f)) {
+                    // Avoid zero vectors
+                    vector.set(randomIntBetween(0, numDims - 1), 1.0f);
                 }
                 docs[i] = prepareIndex("test").setId("" + i).setSource("id", String.valueOf(i), "vector", vector);
                 indexedVectors.put(i, vector);