Fix for handling special characters in attribute names with WRITE_IF_NOT_EXISTS update behavior

Author: bmaizels

.changes/next-release/bugfix-AmazonDynamoDBEnhancedClient-6338e31.json

@@ -0,0 +1,5 @@
+{
+    "type": "bugfix",
+    "category": "Amazon DynamoDB Enhanced Client",
+    "description": "Fix for handling special characters in attribute names with WRITE_IF_NOT_EXISTS update behavior"
+}

services-custom/dynamodb-enhanced/src/main/java/software/amazon/awssdk/enhanced/dynamodb/internal/operations/UpdateItemOperation.java

@@ -59,7 +59,8 @@ public class UpdateItemOperation<T>
         key -> "#AMZN_MAPPED_" + EnhancedClientUtils.cleanAttributeName(key);
 
     private static final Function<String, String> CONDITIONAL_UPDATE_MAPPER =
-        key -> "if_not_exists(" + key + ", " + EXPRESSION_VALUE_KEY_MAPPER.apply(key) + ")";
+        key -> "if_not_exists(" + EXPRESSION_KEY_MAPPER.apply(key) + ", " +
+                EXPRESSION_VALUE_KEY_MAPPER.apply(key) + ")";
 
     private final UpdateItemEnhancedRequest<T> request;
 

services-custom/dynamodb-enhanced/src/test/java/software/amazon/awssdk/enhanced/dynamodb/functionaltests/models/RecordWithUpdateBehaviors.java

@@ -17,6 +17,7 @@
 
 import java.time.Instant;
 import software.amazon.awssdk.enhanced.dynamodb.extensions.annotations.DynamoDbVersionAttribute;
+import software.amazon.awssdk.enhanced.dynamodb.mapper.annotations.DynamoDbAttribute;
 import software.amazon.awssdk.enhanced.dynamodb.mapper.annotations.DynamoDbBean;
 import software.amazon.awssdk.enhanced.dynamodb.mapper.annotations.DynamoDbPartitionKey;
 import software.amazon.awssdk.enhanced.dynamodb.mapper.annotations.DynamoDbUpdateBehavior;
@@ -41,6 +42,7 @@ public void setId(String id) {
     }
 
     @DynamoDbUpdateBehavior(WRITE_IF_NOT_EXISTS)
+    @DynamoDbAttribute("created-on")                           // Forces a test on attribute name cleaning
     public Instant getCreatedOn() {
         return createdOn;
     }