Fix parsing of flattened fields within subobjects: false (#105373)

Author: felixbarny

docs/changelog/105373.yaml

@@ -0,0 +1,5 @@
+pr: 105373
+summary: "Fix parsing of flattened fields within subobjects: false"
+area: Mapping
+type: bug
+issues: []

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

@@ -455,11 +455,12 @@ private static void parseObject(final DocumentParserContext context, String curr
 
     private static void doParseObject(DocumentParserContext context, String currentFieldName, Mapper objectMapper) throws IOException {
         context.path().add(currentFieldName);
+        boolean withinLeafObject = context.path().isWithinLeafObject();
         if (objectMapper instanceof ObjectMapper objMapper && objMapper.subobjects() == false) {
             context.path().setWithinLeafObject(true);
         }
         parseObjectOrField(context, objectMapper);
-        context.path().setWithinLeafObject(false);
+        context.path().setWithinLeafObject(withinLeafObject);
         context.path().remove();
     }
 

server/src/test/java/org/elasticsearch/index/mapper/DocumentParserTests.java

@@ -2273,6 +2273,39 @@ public void testSubobjectsFalseParentDynamicFalse() throws Exception {
         assertNull(doc.dynamicMappingsUpdate());
     }
 
+    public void testSubobjectsFalseFlattened() throws Exception {
+        DocumentMapper mapper = createDocumentMapper(mapping(b -> {
+            b.startObject("attributes");
+            {
+                b.field("dynamic", false);
+                b.field("subobjects", false);
+                b.startObject("properties");
+                {
+                    b.startObject("simple.attribute");
+                    b.field("type", "keyword");
+                    b.endObject();
+                    b.startObject("complex.attribute");
+                    b.field("type", "flattened");
+                    b.endObject();
+                }
+                b.endObject();
+            }
+            b.endObject();
+        }));
+        ParsedDocument doc = mapper.parse(source("""
+            {
+              "attributes": {
+                "complex.attribute": {
+                  "foo" : "bar"
+                },
+                "simple.attribute": "foo"
+              }
+            }
+            """));
+        assertNotNull(doc.rootDoc().getField("attributes.complex.attribute"));
+        assertNotNull(doc.rootDoc().getField("attributes.simple.attribute"));
+    }
+
     public void testWriteToFieldAlias() throws Exception {
         DocumentMapper mapper = createDocumentMapper(mapping(b -> {
             b.startObject("alias-field");

server/src/test/java/org/elasticsearch/index/mapper/DynamicTemplatesTests.java

@@ -1807,6 +1807,53 @@ public void testSubobjectsFalseDocWithEmptyObject() throws IOException {
         assertFalse(leaf.subobjects());
     }
 
+    public void testSubobjectsFalseFlattened() throws IOException {
+        String mapping = """
+            {
+              "_doc": {
+                "properties": {
+                  "attributes": {
+                    "type": "object",
+                    "subobjects": false
+                  }
+                },
+                "dynamic_templates": [
+                  {
+                    "test": {
+                      "path_match": "attributes.*",
+                      "match_mapping_type": "object",
+                      "mapping": {
+                        "type": "flattened"
+                      }
+                    }
+                  }
+                ]
+              }
+            }
+            """;
+        String docJson = """
+            {
+              "attributes": {
+                "complex.attribute": {
+                  "a": "b"
+                },
+                "foo.bar": "baz"
+              }
+            }
+            """;
+
+        MapperService mapperService = createMapperService(mapping);
+        ParsedDocument parsedDoc = mapperService.documentMapper().parse(source(docJson));
+        merge(mapperService, dynamicMapping(parsedDoc.dynamicMappingsUpdate()));
+
+        Mapper fooBarMapper = mapperService.documentMapper().mappers().getMapper("attributes.foo.bar");
+        assertNotNull(fooBarMapper);
+        assertEquals("text", fooBarMapper.typeName());
+        Mapper fooStructuredMapper = mapperService.documentMapper().mappers().getMapper("attributes.complex.attribute");
+        assertNotNull(fooStructuredMapper);
+        assertEquals("flattened", fooStructuredMapper.typeName());
+    }
+
     public void testMatchWithArrayOfFieldNames() throws IOException {
         String mapping = """
             {