Fix multivalued fields

Author: jordan-powers

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

@@ -17,18 +17,16 @@
 
 import java.io.IOException;
 
-public abstract class BinaryDocValuesSyntheticFieldLoaderLayer implements CompositeSyntheticFieldLoader.DocValuesLayer {
+public final class BinaryDocValuesSyntheticFieldLoaderLayer implements CompositeSyntheticFieldLoader.DocValuesLayer {
 
     private final String name;
     private SortedBinaryDocValues bytesValues;
     private boolean hasValue;
 
-    protected BinaryDocValuesSyntheticFieldLoaderLayer(String name) {
+    public BinaryDocValuesSyntheticFieldLoaderLayer(String name) {
         this.name = name;
     }
 
-    protected abstract void writeValue(XContentBuilder b, BytesRef value) throws IOException;
-
     @Override
     public long valueCount() {
         return bytesValues == null ? 0 : bytesValues.docValueCount();
@@ -61,7 +59,10 @@ public void write(XContentBuilder b) throws IOException {
             return;
         }
 
-        writeValue(b, bytesValues.nextValue());
+        for (int i = 0; i < bytesValues.docValueCount(); ++i) {
+            BytesRef value = bytesValues.nextValue();
+            b.utf8Value(value.bytes, value.offset, value.length);
+        }
     }
 
     @Override

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

@@ -1497,25 +1497,15 @@ protected BytesRef preserve(BytesRef value) {
             } else {
                 assert offsetsFieldName == null;
                 assert indexSettings.sourceKeepMode() == SourceKeepMode.NONE;
-                layers.add(new BinaryDocValuesSyntheticFieldLoaderLayer(fieldType().binaryDocValuesName()) {
-                    @Override
-                    protected void writeValue(XContentBuilder b, BytesRef value) throws IOException {
-                        b.utf8Value(value.bytes, value.offset, value.length);
-                    }
-                });
+                layers.add(new BinaryDocValuesSyntheticFieldLoaderLayer(fieldType().binaryDocValuesName()));
             }
         }
 
         // if ignore_above is set, then there is a chance that this field will be ignored. In such cases, we save an
         // extra copy of the field for supporting synthetic source. This layer will check that copy.
         if (fieldType().ignoreAbove.valuesPotentiallyIgnored()) {
             final String fieldName = fieldType().syntheticSourceFallbackFieldName();
-            layers.add(new BinaryDocValuesSyntheticFieldLoaderLayer(fieldName) {
-                @Override
-                public void writeValue(XContentBuilder b, BytesRef value) throws IOException {
-                    b.utf8Value(value.bytes, value.offset, value.length);
-                }
-            });
+            layers.add(new BinaryDocValuesSyntheticFieldLoaderLayer(fieldName));
         }
 
         return new CompositeSyntheticFieldLoader(leafFieldName, fullFieldName, layers);

x-pack/plugin/wildcard/src/main/java/org/elasticsearch/xpack/wildcard/mapper/WildcardFieldMapper.java

@@ -1104,12 +1104,7 @@ public FieldMapper.Builder getMergeBuilder() {
     protected SyntheticSourceSupport syntheticSourceSupport() {
         return new SyntheticSourceSupport.Native(() -> {
             var layers = new ArrayList<CompositeSyntheticFieldLoader.Layer>();
-            layers.add(new BinaryDocValuesSyntheticFieldLoaderLayer(fullPath()) {
-                @Override
-                protected void writeValue(XContentBuilder b, BytesRef value) throws IOException {
-                    b.utf8Value(value.bytes, value.offset, value.length);
-                }
-            });
+            layers.add(new BinaryDocValuesSyntheticFieldLoaderLayer(fullPath()));
             if (ignoreAbove.valuesPotentiallyIgnored()) {
                 layers.add(new CompositeSyntheticFieldLoader.StoredFieldLayer(originalName()) {
                     @Override