Added fix in exists query builder to skip queries generation for virtual fields

Signed-off-by: Mrudhul Guda <gm13@iitbbs.ac.in>

Author: Luci-MG

modules/mapper-extras/src/main/java/org/opensearch/index/mapper/SearchAsYouTypeFieldMapper.java

@@ -454,6 +454,11 @@ public String typeName() {
         public String toString() {
             return super.toString() + ",prefixChars=" + minChars + ":" + maxChars;
         }
+
+        @Override
+        public Query existsQuery(QueryShardContext context) {
+            throw new UnsupportedOperationException();
+        }
     }
 
     static final class PrefixFieldMapper extends FieldMapper {

modules/mapper-extras/src/test/java/org/opensearch/index/mapper/SearchAsYouTypeFieldMapperTests.java

@@ -563,10 +563,8 @@ public void testNestedExistsQuery() throws IOException {
         QueryShardContext queryShardContext = createQueryShardContext(mapperService);
         Query actual = new QueryStringQueryBuilder("field:*").toQuery(queryShardContext);
         Query expected = new ConstantScoreQuery(
-            new BooleanQuery.Builder().add(new NormsFieldExistsQuery("field.nested_field"), BooleanClause.Occur.SHOULD)
-                .add(new NormsFieldExistsQuery("field.nested_field._3gram"), BooleanClause.Occur.SHOULD)
-                .add(new NormsFieldExistsQuery("field.nested_field._2gram"), BooleanClause.Occur.SHOULD)
-                .add(new TermQuery(new Term("_field_names", "field.nested_field._index_prefix")), BooleanClause.Occur.SHOULD)
+            new BooleanQuery.Builder()
+                .add(new NormsFieldExistsQuery("field.nested_field"), BooleanClause.Occur.SHOULD)
                 .build()
         );
         assertEquals(expected, actual);

server/src/main/java/org/opensearch/index/query/ExistsQueryBuilder.java

@@ -201,6 +201,11 @@ private static Query newObjectFieldExistsQuery(QueryShardContext context, String
         BooleanQuery.Builder booleanQuery = new BooleanQuery.Builder();
         Collection<String> fields = context.simpleMatchToIndexNames(objField + ".*");
         for (String field : fields) {
+            int dotPos = field.lastIndexOf('.');
+            if (dotPos > 0 && field.charAt(dotPos + 1) == '_') {
+                // This is a subfield (e.g. prefix) of a complex field type. Skip it.
+                continue;
+            }
             Query existsQuery = context.getMapperService().fieldType(field).existsQuery(context);
             booleanQuery.add(existsQuery, Occur.SHOULD);
         }