elastic · original-brownbear · Apr 22, 2025 · Apr 22, 2025
diff --git a/...olator/src/main/java/org/elasticsearch/percolator/PercolatorMatchedSlotSubFetchPhase.java b/...olator/src/main/java/org/elasticsearch/percolator/PercolatorMatchedSlotSubFetchPhase.java
@@ -100,7 +100,7 @@ public void process(HitContext hitContext) throws IOException {
                     IntStream slots = convertTopDocsToSlots(topDocs, pc.rootDocsBySlot);
                     // _percolator_document_slot fields are document fields and should be under "fields" section in a hit
                     List<Object> docSlots = slots.boxed().collect(Collectors.toList());
-                    hitContext.hit().setDocumentField(fieldName, new DocumentField(fieldName, docSlots));
+                    hitContext.hit().setDocumentField(new DocumentField(fieldName, docSlots));
 
                     // Add info what sub-queries of percolator query matched this each percolated document
                     if (fetchContext.getSearchExecutionContext().hasNamedQueries()) {
@@ -120,7 +120,7 @@ public void process(HitContext hitContext) throws IOException {
                                 matchedQueries.add(match.getName());
                             }
                             String matchedFieldName = fieldName + "_" + docSlots.get(i) + "_matched_queries";
-                            hitContext.hit().setDocumentField(matchedFieldName, new DocumentField(matchedFieldName, matchedQueries));
+                            hitContext.hit().setDocumentField(new DocumentField(matchedFieldName, matchedQueries));
                         }
                     }
                 }

diff --git a/...src/internalClusterTest/java/org/elasticsearch/search/aggregations/metrics/TopHitsIT.java b/...src/internalClusterTest/java/org/elasticsearch/search/aggregations/metrics/TopHitsIT.java
@@ -1327,8 +1327,7 @@ public void setNextReader(LeafReaderContext ctx) {
                         public void process(FetchSubPhase.HitContext hitContext) {
                             leafSearchLookup.setDocument(hitContext.docId());
                             FieldLookup fieldLookup = leafSearchLookup.fields().get("text");
-                            hitContext.hit()
-                                .setDocumentField("text_stored_lookup", new DocumentField("text_stored_lookup", fieldLookup.getValues()));
+                            hitContext.hit().setDocumentField(new DocumentField("text_stored_lookup", fieldLookup.getValues()));
                         }
 
                         @Override

diff --git a/...er/src/internalClusterTest/java/org/elasticsearch/search/fetch/FetchSubPhasePluginIT.java b/...er/src/internalClusterTest/java/org/elasticsearch/search/fetch/FetchSubPhasePluginIT.java
@@ -137,7 +137,7 @@ private void hitExecute(FetchContext context, HitContext hitContext) throws IOEx
             DocumentField hitField = hitContext.hit().getFields().get(NAME);
             if (hitField == null) {
                 hitField = new DocumentField(NAME, new ArrayList<>(1));
-                hitContext.hit().setDocumentField(NAME, hitField);
+                hitContext.hit().setDocumentField(hitField);
             }
             Terms terms = hitContext.reader().termVectors().get(hitContext.docId(), field);
             if (terms != null) {

diff --git a/server/src/main/java/org/elasticsearch/TransportVersions.java b/server/src/main/java/org/elasticsearch/TransportVersions.java
@@ -233,6 +233,7 @@ static TransportVersion def(int id) {
     public static final TransportVersion SEARCH_INCREMENTAL_TOP_DOCS_NULL = def(9_058_0_00);
     public static final TransportVersion COMPRESS_DELAYABLE_WRITEABLE = def(9_059_0_00);
     public static final TransportVersion SYNONYMS_REFRESH_PARAM = def(9_060_0_00);
+    public static final TransportVersion DOC_FIELDS_AS_LIST = def(9_061_0_00);
 
     /*
      * STOP! READ THIS FIRST! No, really,

@@ -24,6 +24,7 @@
 import java.util.Collections;
 import java.util.Iterator;
 import java.util.List;
+import java.util.Map;
 import java.util.Objects;
 
 import static org.elasticsearch.common.xcontent.XContentParserUtils.ensureExpectedToken;
@@ -70,6 +71,15 @@ public DocumentField(String name, List<Object> values, List<Object> ignoredValue
             : "DocumentField can't have both lookup fields and values";
     }
 
+    /**
+     * Read map of document fields written via {@link StreamOutput#writeMapValues(Map)}.
+     * @param in stream input
+     * @return map of {@link DocumentField} keyed by {@link DocumentField#getName()}
+     */
+    public static Map<String, DocumentField> readFieldsFromMapValues(StreamInput in) throws IOException {
+        return in.readMapValues(DocumentField::new, DocumentField::getName);
+    }
+
     /**
      * The name of the field.
      */

diff --git a/server/src/main/java/org/elasticsearch/index/get/GetResult.java b/server/src/main/java/org/elasticsearch/index/get/GetResult.java
@@ -74,8 +74,8 @@ public GetResult(StreamInput in) throws IOException {
             if (source.length() == 0) {
                 source = null;
             }
-            documentFields = in.readMapValues(DocumentField::new, DocumentField::getName);
-            metaFields = in.readMapValues(DocumentField::new, DocumentField::getName);
+            documentFields = DocumentField.readFieldsFromMapValues(in);
+            metaFields = DocumentField.readFieldsFromMapValues(in);
         } else {
             metaFields = Collections.emptyMap();
             documentFields = Collections.emptyMap();

diff --git a/server/src/main/java/org/elasticsearch/search/SearchHit.java b/server/src/main/java/org/elasticsearch/search/SearchHit.java
@@ -216,8 +216,15 @@ public static SearchHit readFrom(StreamInput in, boolean pooled) throws IOExcept
         if (in.readBoolean()) {
             explanation = readExplanation(in);
         }
-        final Map<String, DocumentField> documentFields = in.readMap(DocumentField::new);
-        final Map<String, DocumentField> metaFields = in.readMap(DocumentField::new);
+        final Map<String, DocumentField> documentFields;
+        final Map<String, DocumentField> metaFields;
+        if (in.getTransportVersion().onOrAfter(TransportVersions.DOC_FIELDS_AS_LIST)) {
+            documentFields = DocumentField.readFieldsFromMapValues(in);
+            metaFields = DocumentField.readFieldsFromMapValues(in);
+        } else {
+            documentFields = in.readMap(DocumentField::new);
+            metaFields = in.readMap(DocumentField::new);
+        }
         Map<String, HighlightField> highlightFields = in.readMapValues(HighlightField::new, HighlightField::name);
         highlightFields = highlightFields.isEmpty() ? null : unmodifiableMap(highlightFields);
 
@@ -322,8 +329,13 @@ public void writeTo(StreamOutput out) throws IOException {
             out.writeBoolean(true);
             writeExplanation(out, explanation);
         }
-        out.writeMap(documentFields, StreamOutput::writeWriteable);
-        out.writeMap(metaFields, StreamOutput::writeWriteable);
+        if (out.getTransportVersion().onOrAfter(TransportVersions.DOC_FIELDS_AS_LIST)) {
+            out.writeMapValues(documentFields);
+            out.writeMapValues(metaFields);
+        } else {
+            out.writeMap(documentFields, StreamOutput::writeWriteable);
+            out.writeMap(metaFields, StreamOutput::writeWriteable);
+        }
         if (highlightFields == null) {
             out.writeVInt(0);
         } else {
@@ -502,9 +514,9 @@ public DocumentField field(String fieldName) {
     /*
     * Adds a new DocumentField to the map in case both parameters are not null.
     * */
-    public void setDocumentField(String fieldName, DocumentField field) {
-        if (fieldName == null || field == null) return;
-        this.documentFields.put(fieldName, field);
+    public void setDocumentField(DocumentField field) {
+        if (field == null) return;
+        this.documentFields.put(field.getName(), field);
     }
 
     public void addDocumentFields(Map<String, DocumentField> docFields, Map<String, DocumentField> metaFields) {

diff --git a/server/src/main/java/org/elasticsearch/search/fetch/subphase/FetchDocValuesPhase.java b/server/src/main/java/org/elasticsearch/search/fetch/subphase/FetchDocValuesPhase.java
@@ -76,7 +76,7 @@ public void process(HitContext hit) throws IOException {
                         hitField = new DocumentField(f.field, new ArrayList<>(2));
                         // even if we request a doc values of a meta-field (e.g. _routing),
                         // docValues fields will still be document fields, and put under "fields" section of a hit.
-                        hit.hit().setDocumentField(f.field, hitField);
+                        hit.hit().setDocumentField(hitField);
                     }
                     List<Object> ignoredValues = new ArrayList<>();
                     hitField.getValues().addAll(f.fetcher.fetchValues(hit.source(), hit.docId(), ignoredValues));

diff --git a/server/src/main/java/org/elasticsearch/search/fetch/subphase/ScriptFieldsPhase.java b/server/src/main/java/org/elasticsearch/search/fetch/subphase/ScriptFieldsPhase.java
@@ -75,7 +75,7 @@ public void process(HitContext hitContext) {
                         }
                         hitField = new DocumentField(scriptFieldName, values);
                         // script fields are never meta-fields
-                        hitContext.hit().setDocumentField(scriptFieldName, hitField);
+                        hitContext.hit().setDocumentField(hitField);
                     }
                 }
             }

diff --git a/server/src/main/java/org/elasticsearch/search/fetch/subphase/StoredFieldsPhase.java b/server/src/main/java/org/elasticsearch/search/fetch/subphase/StoredFieldsPhase.java
@@ -95,8 +95,7 @@ public void process(HitContext hitContext) {
                 Map<String, List<Object>> loadedFields = hitContext.loadedFields();
                 for (StoredField storedField : storedFields) {
                     if (storedField.hasValue(loadedFields)) {
-                        hitContext.hit()
-                            .setDocumentField(storedField.name, new DocumentField(storedField.name, storedField.process(loadedFields)));
+                        hitContext.hit().setDocumentField(new DocumentField(storedField.name, storedField.process(loadedFields)));
                     }
                 }
             }

diff --git a/server/src/test/java/org/elasticsearch/action/search/ExpandSearchPhaseTests.java b/server/src/test/java/org/elasticsearch/action/search/ExpandSearchPhaseTests.java
@@ -116,7 +116,7 @@ void sendExecuteMultiSearch(MultiSearchRequest request, SearchTask task, ActionL
                 };
 
                 SearchHit hit = new SearchHit(1, "ID");
-                hit.setDocumentField("someField", new DocumentField("someField", Collections.singletonList(collapseValue)));
+                hit.setDocumentField(new DocumentField("someField", Collections.singletonList(collapseValue)));
                 ExpandSearchPhase phase = newExpandSearchPhase(
                     mockSearchPhaseContext,
                     new SearchResponseSections(
@@ -188,9 +188,9 @@ void sendExecuteMultiSearch(MultiSearchRequest request, SearchTask task, ActionL
         };
 
         SearchHit hit1 = new SearchHit(1, "ID");
-        hit1.setDocumentField("someField", new DocumentField("someField", Collections.singletonList(collapseValue)));
+        hit1.setDocumentField(new DocumentField("someField", Collections.singletonList(collapseValue)));
         SearchHit hit2 = new SearchHit(2, "ID2");
-        hit2.setDocumentField("someField", new DocumentField("someField", Collections.singletonList(collapseValue)));
+        hit2.setDocumentField(new DocumentField("someField", Collections.singletonList(collapseValue)));
         try (
             SearchResponseSections searchResponseSections = new SearchResponseSections(
                 new SearchHits(new SearchHit[] { hit1, hit2 }, new TotalHits(1, TotalHits.Relation.EQUAL_TO), 1.0F),
@@ -225,9 +225,9 @@ void sendExecuteMultiSearch(MultiSearchRequest request, SearchTask task, ActionL
             };
 
             SearchHit hit1 = new SearchHit(1, "ID");
-            hit1.setDocumentField("someField", new DocumentField("someField", Collections.singletonList(null)));
+            hit1.setDocumentField(new DocumentField("someField", Collections.singletonList(null)));
             SearchHit hit2 = new SearchHit(2, "ID2");
-            hit2.setDocumentField("someField", new DocumentField("someField", Collections.singletonList(null)));
+            hit2.setDocumentField(new DocumentField("someField", Collections.singletonList(null)));
             ExpandSearchPhase phase = newExpandSearchPhase(
                 mockSearchPhaseContext,
                 new SearchResponseSections(
@@ -313,7 +313,7 @@ void sendExecuteMultiSearch(MultiSearchRequest request, SearchTask task, ActionL
                 .routing("baz");
 
             SearchHit hit = new SearchHit(1, "ID");
-            hit.setDocumentField("someField", new DocumentField("someField", Collections.singletonList("foo")));
+            hit.setDocumentField(new DocumentField("someField", Collections.singletonList("foo")));
             try (
                 SearchResponseSections searchResponseSections = new SearchResponseSections(
                     new SearchHits(new SearchHit[] { hit }, new TotalHits(1, TotalHits.Relation.EQUAL_TO), 1.0F),
@@ -384,7 +384,7 @@ void sendExecuteMultiSearch(MultiSearchRequest request, SearchTask task, ActionL
                 .routing("baz");
 
             SearchHit hit = new SearchHit(1, "ID");
-            hit.setDocumentField("someField", new DocumentField("someField", Collections.singletonList("foo")));
+            hit.setDocumentField(new DocumentField("someField", Collections.singletonList("foo")));
             try (
                 SearchResponseSections searchResponseSections = new SearchResponseSections(
                     new SearchHits(new SearchHit[] { hit }, new TotalHits(1, TotalHits.Relation.EQUAL_TO), 1.0F),

diff --git a/server/src/test/java/org/elasticsearch/action/search/FetchLookupFieldsPhaseTests.java b/server/src/test/java/org/elasticsearch/action/search/FetchLookupFieldsPhaseTests.java
@@ -108,7 +108,7 @@ void sendExecuteMultiSearch(
                         final SearchHits searchHits;
                         if (fields != null) {
                             final SearchHit hit = new SearchHit(randomInt(1000));
-                            fields.forEach((f, values) -> hit.setDocumentField(f, new DocumentField(f, values, List.of())));
+                            fields.forEach((f, values) -> hit.setDocumentField(new DocumentField(f, values, List.of())));
                             searchHits = new SearchHits(new SearchHit[] { hit }, new TotalHits(1, TotalHits.Relation.EQUAL_TO), 1.0f);
                         } else {
                             searchHits = SearchHits.empty(new TotalHits(0, TotalHits.Relation.EQUAL_TO), 1.0f);
@@ -143,7 +143,6 @@ void sendExecuteMultiSearch(
             final List<FieldAndFormat> fetchFields = List.of(new FieldAndFormat(randomAlphaOfLength(10), null));
             {
                 leftHit0.setDocumentField(
-                    "lookup_field_1",
                     new DocumentField(
                         "lookup_field_1",
                         List.of(),
@@ -155,7 +154,6 @@ void sendExecuteMultiSearch(
                     )
                 );
                 leftHit0.setDocumentField(
-                    "lookup_field_2",
                     new DocumentField(
                         "lookup_field_2",
                         List.of(),
@@ -168,7 +166,6 @@ void sendExecuteMultiSearch(
             SearchHit leftHit1 = new SearchHit(randomInt(100));
             {
                 leftHit1.setDocumentField(
-                    "lookup_field_2",
                     new DocumentField(
                         "lookup_field_2",
                         List.of(),
@@ -180,7 +177,6 @@ void sendExecuteMultiSearch(
                     )
                 );
                 leftHit1.setDocumentField(
-                    "lookup_field_3",
                     new DocumentField(
                         "lookup_field_3",
                         List.of(),

diff --git a/server/src/test/java/org/elasticsearch/action/search/RankFeaturePhaseTests.java b/server/src/test/java/org/elasticsearch/action/search/RankFeaturePhaseTests.java
@@ -967,7 +967,7 @@ private void buildRankFeatureResult(
             searchHits[i] = SearchHit.unpooled(scoreDocs[i].doc);
             searchHits[i].shard(shardTarget);
             searchHits[i].score(scoreDocs[i].score);
-            searchHits[i].setDocumentField(DEFAULT_FIELD, new DocumentField(DEFAULT_FIELD, Collections.singletonList(scoreDocs[i].doc)));
+            searchHits[i].setDocumentField(new DocumentField(DEFAULT_FIELD, Collections.singletonList(scoreDocs[i].doc)));
             if (scoreDocs[i].score > maxScore) {
                 maxScore = scoreDocs[i].score;
             }

diff --git a/server/src/test/java/org/elasticsearch/search/rank/RankFeatureShardPhaseTests.java b/server/src/test/java/org/elasticsearch/search/rank/RankFeatureShardPhaseTests.java
@@ -297,16 +297,13 @@ public void testProcessFetch() {
             searchContext.addFetchResult();
             SearchHit[] hits = new SearchHit[3];
             hits[0] = SearchHit.unpooled(4);
-            hits[0].setDocumentField(fieldName, new DocumentField(fieldName, Collections.singletonList(expectedFieldData.get(4))));
+            hits[0].setDocumentField(new DocumentField(fieldName, Collections.singletonList(expectedFieldData.get(4))));
 
             hits[1] = SearchHit.unpooled(9);
-            hits[1].setDocumentField(fieldName, new DocumentField(fieldName, Collections.singletonList(expectedFieldData.get(9))));
+            hits[1].setDocumentField(new DocumentField(fieldName, Collections.singletonList(expectedFieldData.get(9))));
 
             hits[2] = SearchHit.unpooled(numDocs - 1);
-            hits[2].setDocumentField(
-                fieldName,
-                new DocumentField(fieldName, Collections.singletonList(expectedFieldData.get(numDocs - 1)))
-            );
+            hits[2].setDocumentField(new DocumentField(fieldName, Collections.singletonList(expectedFieldData.get(numDocs - 1))));
             searchHits = SearchHits.unpooled(hits, new TotalHits(3, TotalHits.Relation.EQUAL_TO), 1.0f);
             searchContext.fetchResult().shardResult(searchHits, null);
             when(searchContext.isCancelled()).thenReturn(false);

diff --git a/x-pack/plugin/ml/src/test/java/org/elasticsearch/xpack/ml/test/SearchHitBuilder.java b/x-pack/plugin/ml/src/test/java/org/elasticsearch/xpack/ml/test/SearchHitBuilder.java
@@ -30,7 +30,7 @@ public SearchHitBuilder addField(String name, Object value) {
     }
 
     public SearchHitBuilder addField(String name, List<Object> values) {
-        hit.setDocumentField(name, new DocumentField(name, values));
+        hit.setDocumentField(new DocumentField(name, values));
         return this;
     }
 

diff --git a/.../java/org/elasticsearch/xpack/sql/execution/search/extractor/ComputingExtractorTests.java b/.../java/org/elasticsearch/xpack/sql/execution/search/extractor/ComputingExtractorTests.java
@@ -83,7 +83,7 @@ public void testGet() {
             double expected = Math.log(value);
             DocumentField field = new DocumentField(fieldName, singletonList(value));
             SearchHit hit = SearchHit.unpooled(1, null);
-            hit.setDocumentField(fieldName, field);
+            hit.setDocumentField(field);
             assertEquals(expected, extractor.process(hit));
         }
     }