[BUG FIX] Fix the visit of inner query for NestedQueryBuilder

CHANGELOG.md

@@ -74,6 +74,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/),
 - Refactoring Grok.validatePatternBank by using an iterative approach ([#14206](https://github.com/opensearch-project/OpenSearch/pull/14206))
 - Update help output for _cat ([#14722](https://github.com/opensearch-project/OpenSearch/pull/14722))
 - Fix bulk upsert ignores the default_pipeline and final_pipeline when auto-created index matches the index template ([#12891](https://github.com/opensearch-project/OpenSearch/pull/12891))
+- Fix the visit of inner query for NestedQueryBuilder ([#14739](https://github.com/opensearch-project/OpenSearch/pull/14739))
 
 ### Security
 

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

@@ -34,6 +34,7 @@
 
 import org.apache.lucene.index.LeafReaderContext;
 import org.apache.lucene.index.ReaderUtil;
+import org.apache.lucene.search.BooleanClause;
 import org.apache.lucene.search.MatchNoDocsQuery;
 import org.apache.lucene.search.MultiCollector;
 import org.apache.lucene.search.Query;
@@ -505,4 +506,12 @@ public TopDocsAndMaxScore topDocs(SearchHit hit) throws IOException {
             }
         }
     }
+
+    @Override
+    public void visit(QueryBuilderVisitor visitor) {
+        visitor.accept(this);
+        if (query != null) {
+            visitor.getChildVisitor(BooleanClause.Occur.MUST).accept(query);
+        }
+    }
 }

server/src/test/java/org/opensearch/index/query/NestedQueryBuilderTests.java

@@ -59,8 +59,10 @@
 import org.hamcrest.Matchers;
 
 import java.io.IOException;
+import java.util.ArrayList;
 import java.util.Collections;
 import java.util.HashMap;
+import java.util.List;
 import java.util.Map;
 import java.util.Optional;
 
@@ -565,4 +567,13 @@ void doWithDepth(int depth, ThrowingConsumer<QueryShardContext> test) throws Exc
                 );
         }
     }
+
+    public void testVisit() {
+        NestedQueryBuilder builder = new NestedQueryBuilder("path", new MatchAllQueryBuilder(), ScoreMode.None);
+
+        List<QueryBuilder> visitedQueries = new ArrayList<>();
+        builder.visit(createTestVisitor(visitedQueries));
+
+        assertEquals(2, visitedQueries.size());
+    }
 }