Fixed DynamoDbEnhancedClient TableSchema::itemToMap to handle flattened members when ignoreNulls is false

Author: iulianbudau

.changes/next-release/bugfix-AmazonDynamoDBEnhancedClient-752432f.json

@@ -0,0 +1,6 @@
+{
+    "type": "bugfix",
+    "category": "Amazon DynamoDB Enhanced Client",
+    "contributor": "",
+    "description": "Fixed DynamoDbEnhancedClient TableSchema::itemToMap to return a map that contains a consistent representation of null top-level (non-flattened) attributes and flattened attributes when their enclosing member is null and ignoreNulls is set to false."
+}

CHANGELOG.md

@@ -1,4 +1,9 @@
  #### 👋 _Looking for changelogs for older versions? You can find them in the [changelogs](./changelogs) directory._
+# __2.30.8__ __2025-01-28__
+## __Amazon DynamoDB Enhanced Client__
+  - ### Bugfixes
+    - Fixed DynamoDbEnhancedClient TableSchema::itemToMap doesn't respect ignoreNulls with null @DynamoDbFlattened members. See [#2540](https://github.com/aws/aws-sdk-java-v2/issues/2540)
+
 # __2.30.7__ __2025-01-27__
 ## __AWS Elemental MediaConvert__
   - ### Features

services-custom/dynamodb-enhanced/src/main/java/software/amazon/awssdk/enhanced/dynamodb/mapper/StaticImmutableTableSchema.java

@@ -126,7 +126,7 @@ private B mapToItem(B thisBuilder,
         private Map<String, AttributeValue> itemToMap(T item, boolean ignoreNulls) {
             T1 otherItem = this.otherItemGetter.apply(item);
 
-            if (otherItem == null) {
+            if (otherItem == null && ignoreNulls) {
                 return Collections.emptyMap();
             }
 
@@ -515,7 +515,9 @@ public Map<String, AttributeValue> itemToMap(T item, boolean ignoreNulls) {
 
         attributeMappers.forEach(attributeMapper -> {
             String attributeKey = attributeMapper.attributeName();
-            AttributeValue attributeValue = attributeMapper.attributeGetterMethod().apply(item);
+            AttributeValue attributeValue = item == null ?
+                                            AttributeValue.fromNul(true) :
+                                            attributeMapper.attributeGetterMethod().apply(item);
 
             if (!ignoreNulls || !isNullAttributeValue(attributeValue)) {
                 attributeValueMap.put(attributeKey, attributeValue);

services-custom/dynamodb-enhanced/src/test/java/software/amazon/awssdk/enhanced/dynamodb/mapper/StaticImmutableTableSchemaTest.java

@@ -1386,6 +1386,11 @@ public void buildAbstractWithFlatten() {
 
         assertThat(tableSchema.itemToMap(item, true),
                    is(singletonMap("documentString", AttributeValue.builder().s("test-string").build())));
+
+        Map<String, AttributeValue> attributeMapWithNulls = tableSchema.itemToMap(item, false);
+        assertThat(attributeMapWithNulls.size(), is(2));
+        assertThat(attributeMapWithNulls, hasEntry("documentString", AttributeValue.builder().s("test-string").build()));
+        assertThat(attributeMapWithNulls, hasEntry("documentInteger", AttributeValue.fromNul(true)));
     }
 
     @Test