fix test

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

rest-api-spec/src/main/resources/rest-api-spec/test/index/106_flat_object_with_parameter.yml

@@ -1,7 +1,7 @@
 ---
 # The test setup includes:
 # - Create flat_object mapping for test_flat_object index to test five parameters:
-# - Create test_flat_object1 index to test edge cases:
+# - Create test_flat_object1,test_flat_object2 index to test edge cases:
 # - Index example documents
 # - Refresh the index so it is ready for search tests
 
@@ -68,6 +68,18 @@ setup:
           }
         }
 
+  - do:
+      index:
+        index: test_flat_object
+        id: 4
+        body: {
+          "issue": {
+            "labels": {
+               "age1":null
+            }
+          }
+        }
+
   - do:
       indices.refresh:
         index: test_flat_object
@@ -102,6 +114,44 @@ setup:
       indices.refresh:
         index: test_flat_object1
 
+  # index test_flat_object2
+  - do:
+      indices.create:
+        index: test_flat_object2
+        body:
+          mappings:
+            properties:
+              issue:
+                properties:
+                  labels:
+                    type: flat_object
+
+  - do:
+      index:
+        index: test_flat_object2
+        id: 1
+        body: {
+          "issue": {
+            "labels": {
+              "category": null
+            }
+          }
+        }
+
+  - do:
+      index:
+        index: test_flat_object2
+        id: 2
+        body: {
+          "issue": {
+            "labels": null
+          }
+        }
+
+  - do:
+      indices.refresh:
+        index: test_flat_object2
+
 ---
 # Delete Index when connection is teardown
 teardown:
@@ -145,7 +195,7 @@ teardown:
           }
         }
 
-  - length: { hits.hits: 3 }
+  - length: { hits.hits: 4 }
 
   - do:
       search:
@@ -158,6 +208,17 @@ teardown:
 
   - length: { hits.hits: 1 }
 
+  - do:
+      search:
+        index: test_flat_object2,
+        body: {
+          query: {
+            match_all: { }
+          }
+        }
+
+  - length: { hits.hits: 2 }
+
   # test ignore_above=4.
   - do:
       search:
@@ -211,6 +272,70 @@ teardown:
   - length: { hits.hits: 1 }
   - match: { hits.hits.0._source.issue.labels: null }
 
+  - do:
+      search:
+        index: test_flat_object,
+        body: {
+          _source: true,
+          query: {
+            exists: { field: "issue.labels" }
+          }
+        }
+
+  - length: { hits.hits: 1 }
+  - match: { hits.hits.0._source.issue.labels: null }
+
+  # test null_value="abc" and subField=null.
+  - do:
+      search:
+        index: test_flat_object,
+        body: {
+          _source: true,
+          query: {
+            term: { issue.labels.age1: "abc" }
+          }
+        }
+
+  - length: { hits.hits: 0 }
+
+  # null_value="abc" doesn't work on th subField
+  - do:
+      search:
+        index: test_flat_object,
+        body: {
+          _source: true,
+          query: {
+            exists: { field: "issue.labels.age1" }
+          }
+        }
+
+  - length: { hits.hits: 0 }
+
+  # test null_value=null and subField=null.
+  - do:
+      search:
+        index: test_flat_object2,
+        body: {
+          _source: true,
+          query: {
+            exists: { field: "issue.labels" }
+          }
+        }
+
+  - length: { hits.hits: 0 }
+
+  - do:
+      search:
+        index: test_flat_object2,
+        body: {
+          _source: true,
+          query: {
+            exists: { field: "issue.labels.category" }
+          }
+        }
+
+  - length: { hits.hits: 0 }
+
   # test depth_limit=3.
   - do:
       search:

server/src/main/java/org/opensearch/common/xcontent/JsonToStringXContentParser.java

@@ -137,6 +137,10 @@ private void parseToken(StringBuilder path, String currentFieldName, int depth)
                 if (parseValue(parsedFields)) {
                     this.valueList.add(parsedFields.toString());
                     this.valueAndPathList.add(path + EQUAL_SYMBOL + parsedFields);
+                } else {
+                    // it means that the value is invalid, we should delete the key from keyList.
+                    assert this.keyList.size() > 0;
+                    this.keyList.remove(keyList.size() - 1);
                 }
                 int dotIndex = path.lastIndexOf(DOT_SYMBOL, path.length());
                 if (dotIndex != -1 && path.length() > currentFieldName.length()) {

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

@@ -196,12 +196,20 @@ public void testIgnoreAbove() throws IOException {
     }
 
     public void testNullValue() throws IOException {
+        // test root field is null
         DocumentMapper mapper = createDocumentMapper(fieldMapping(this::minimalMapping));
         ParsedDocument doc = mapper.parse(source(b -> b.nullField("field")));
         assertArrayEquals(new IndexableField[0], doc.rootDoc().getFields("field"));
         assertArrayEquals(new IndexableField[0], doc.rootDoc().getFields("field" + VALUE_SUFFIX));
         assertArrayEquals(new IndexableField[0], doc.rootDoc().getFields("field" + VALUE_AND_PATH_SUFFIX));
 
+        // test subField is null
+        String json = XContentFactory.jsonBuilder().startObject().startObject("field").nullField("Foo").endObject().endObject().toString();
+        doc = mapper.parse(source(json));
+        assertArrayEquals(new IndexableField[0], doc.rootDoc().getFields("field"));
+        assertArrayEquals(new IndexableField[0], doc.rootDoc().getFields("field" + VALUE_SUFFIX));
+        assertArrayEquals(new IndexableField[0], doc.rootDoc().getFields("field" + VALUE_AND_PATH_SUFFIX));
+
         mapper = createDocumentMapper(fieldMapping(b -> b.field("type", "flat_object").field("null_value", "bar")));
         doc = mapper.parse(source(b -> {}));