getting alias fields for field caps

Author: Samiul-TheSoccerFan

server/src/main/java/org/elasticsearch/action/fieldcaps/FieldCapabilitiesFetcher.java

@@ -15,8 +15,8 @@
 import org.elasticsearch.core.Nullable;
 import org.elasticsearch.index.IndexService;
 import org.elasticsearch.index.engine.Engine;
-import org.elasticsearch.index.mapper.FieldMapper;
 import org.elasticsearch.index.mapper.MappedFieldType;
+import org.elasticsearch.index.mapper.Mapper;
 import org.elasticsearch.index.mapper.RootObjectMapper;
 import org.elasticsearch.index.mapper.RuntimeField;
 import org.elasticsearch.index.query.MatchAllQueryBuilder;
@@ -170,16 +170,16 @@ static Map<String, IndexFieldCapabilities> retrieveFieldCaps(
         includeEmptyFields = includeEmptyFields || enableFieldHasValue == false;
         Map<String, IndexFieldCapabilities> responseMap = new HashMap<>();
 
-        // populate field mappers including metadata field mappers
+        // populate with all types of mappers
         RootObjectMapper rootObjectMapper = context.getMappingLookup().getMapping().getRoot();
-        List<FieldMapper> allMappers = new ArrayList<>();
+        List<Mapper> allMappers = new ArrayList<>();
         allMappers.addAll(rootObjectMapper.getSourceFields());
         allMappers.addAll(context.getMetadataFields());
 
-        for (FieldMapper mapper : allMappers) {
+        for (Mapper mapper : allMappers) {
             addFieldToFieldCaps(
                 mapper.fullPath(),
-                mapper.fieldType(),
+                context.getFieldType(mapper.fullPath()),
                 fieldNameFilter,
                 fieldPredicate,
                 filter,

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

@@ -121,8 +121,8 @@ public int getTotalFieldsCount() {
     }
 
     @Override
-    public List<FieldMapper> getSourceFields() {
-        return List.of();
+    public List<Mapper> getSourceFields() {
+        return List.of(this);
     }
 
     public static class TypeParser implements Mapper.TypeParser {

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

@@ -450,8 +450,8 @@ public int getTotalFieldsCount() {
     }
 
     @Override
-    public List<FieldMapper> getSourceFields() {
-        List<FieldMapper> fields = new ArrayList<>();
+    public List<Mapper> getSourceFields() {
+        List<Mapper> fields = new ArrayList<>();
         for (FieldMapper mapper : builderParams.multiFields.mappers) {
             fields.addAll(mapper.getSourceFields());
         }

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

@@ -229,5 +229,5 @@ public String getOffsetFieldName() {
         return null;
     }
 
-    public abstract List<FieldMapper> getSourceFields();
+    public abstract List<Mapper> getSourceFields();
 }

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

@@ -269,8 +269,8 @@ public int getTotalFieldsCount() {
     }
 
     @Override
-    public List<FieldMapper> getSourceFields() {
-        List<FieldMapper> fields = new ArrayList<>();
+    public List<Mapper> getSourceFields() {
+        List<Mapper> fields = new ArrayList<>();
         for (Mapper mapper : mappers.values()) {
             fields.addAll(mapper.getSourceFields());
         }