Change the default value of doc_values in WildcardFieldMapper to true

Signed-off-by: kkewwei <kewei.11@bytedance.com>
Signed-off-by: kkewwei <kkewwei@163.com>

Author: kkewwei

CHANGELOG.md

@@ -31,7 +31,8 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Refactor the ThreadPoolStats.Stats class to use the Builder pattern instead of constructors ([#19317](https://github.com/opensearch-project/OpenSearch/pull/19317))
 - Refactor the IndexingStats.Stats class to use the Builder pattern instead of constructors ([#19306](https://github.com/opensearch-project/OpenSearch/pull/19306))
 - Remove FeatureFlag.MERGED_SEGMENT_WARMER_EXPERIMENTAL_FLAG. ([#19715](https://github.com/opensearch-project/OpenSearch/pull/19715))
--
+- Change the default value of doc_values in WildcardFieldMapper to true. ([#19722](https://github.com/opensearch-project/OpenSearch/pull/19722))
+
 ### Fixed
 - Fix Allocation and Rebalance Constraints of WeightFunction are incorrectly reset ([#19012](https://github.com/opensearch-project/OpenSearch/pull/19012))
 - Fix flaky test FieldDataLoadingIT.testIndicesFieldDataCacheSizeSetting ([#19571](https://github.com/opensearch-project/OpenSearch/pull/19571))

rest-api-spec/src/main/resources/rest-api-spec/test/search/270_wildcard_fieldtype_queries.yml

@@ -19,6 +19,15 @@ setup:
                     type: wildcard
                     doc_values: true
 
+  - do:
+      indices.create:
+        index: test1
+        body:
+          mappings:
+            properties:
+              my_field:
+                type: wildcard
+
   - do:
       index:
         index: test
@@ -78,6 +87,15 @@ setup:
   - do:
       indices.refresh: {}
 
+---
+# Verify that mappings doc_values is stored.
+"Mappings":
+  - do:
+      indices.get_mapping:
+        index: test1
+  - is_true: test1.mappings
+  - match: { test1.mappings.properties.my_field.doc_values: true }
+
 ---
 "term query matches exact value":
   - do:

server/src/main/java/org/opensearch/index/mapper/WildcardFieldMapper.java

@@ -102,7 +102,7 @@ public static final class Builder extends ParametrizedFieldMapper.Builder {
         );
         private final Parameter<String> normalizer = Parameter.stringParam("normalizer", false, m -> toType(m).normalizerName, "default");
         private final Parameter<Map<String, String>> meta = Parameter.metaParam();
-        private final Parameter<Boolean> hasDocValues = Parameter.docValuesParam(m -> toType(m).hasDocValues, false).alwaysSerialize();
+        private final Parameter<Boolean> hasDocValues = Parameter.docValuesParam(m -> toType(m).hasDocValues, true).alwaysSerialize();
         private final IndexAnalyzers indexAnalyzers;
 
         public Builder(String name, IndexAnalyzers indexAnalyzers) {
@@ -328,7 +328,7 @@ public ValueFetcher valueFetcher(QueryShardContext context, SearchLookup searchL
                 throw new IllegalArgumentException("Field [" + name() + "] of type [" + typeName() + "] doesn't " + "support formats.");
             }
 
-            if (hasDocValues()) {
+            if (hasDocValues() && searchLookup != null) {
                 return new DocValueFetcher(DocValueFormat.RAW, searchLookup.doc().getForField(this));
             }
 

server/src/test/java/org/opensearch/index/mapper/WildcardFieldMapperTests.java

@@ -128,9 +128,16 @@ public void testEnableDocValues() throws IOException {
         assertEquals(DocValuesType.NONE, fields[0].fieldType().docValuesType());
         assertEquals(DocValuesType.SORTED_SET, fields[1].fieldType().docValuesType());
 
+        // doc_values is true by default
         mapper = createDocumentMapper(fieldMapping(b -> b.field("type", "wildcard")));
         doc = mapper.parse(source(b -> b.field("field", "1234")));
         fields = doc.rootDoc().getFields("field");
+        assertEquals(2, fields.length);
+        assertEquals(DocValuesType.NONE, fields[0].fieldType().docValuesType());
+
+        mapper = createDocumentMapper(fieldMapping(b -> b.field("type", "wildcard").field("doc_values", false)));
+        doc = mapper.parse(source(b -> b.field("field", "1234")));
+        fields = doc.rootDoc().getFields("field");
         assertEquals(1, fields.length);
         assertEquals(DocValuesType.NONE, fields[0].fieldType().docValuesType());
     }