Fix codegen for implicit event payloads with a single enum field (#3056)

* update codegen for enums

generated/src/aws-cpp-sdk-qbusiness/include/aws/qbusiness/model/ChatInputStream.h

@@ -23,7 +23,7 @@ namespace Model
 {
 
   /**
-   * <p>The streaming input for the <code>Chat</code> API.</p><p><h3>See Also:</h3>  
+   * <p>The streaming input for the <code>Chat</code> API.</p><p><h3>See Also:</h3>
    * <a
    * href="http://docs.aws.amazon.com/goto/WebAPI/qbusiness-2023-11-27/ChatInputStream">AWS
    * API Reference</a></p>
@@ -85,7 +85,8 @@ namespace Model
        Aws::Utils::Event::Message msg;
        msg.InsertEventHeader(":message-type", Aws::String("event"));
        msg.InsertEventHeader(":event-type", Aws::String("AuthChallengeResponseEvent"));
-       AWS_UNREFERENCED_PARAM(value);
+       msg.InsertEventHeader(":content-type", Aws::String("application/json"));
+       msg.WriteEventPayload(value.Jsonize().View().WriteCompact());
        WriteEvent(msg);
        return *this;
     }

tools/code-generation/generator/src/main/java/com/amazonaws/util/awsclientgenerator/transform/C2jModelToGeneratorModelTransformer.java

@@ -305,9 +305,32 @@ header insertion there.  So strip this out of the model (affects S3's PutObjectR
                 } else if (shape.hasEventPayloadMembers() || shape.getMembers().size() == 1) {
                     if (shape.getMembers().size() == 1) {
                         shape.getMembers().entrySet().stream().forEach(memberEntry -> {
-                            memberEntry.getValue().setEventPayload(true);
-                            shape.setEventPayloadMemberName(memberEntry.getKey());
-                            shape.setEventPayloadType(memberEntry.getValue().getShape().getType());
+                            /**
+                             * Note: this is complicated and potentially not completely correct. 
+                             * So touch at your own risk until we have protocol tests supported.
+                             * In summary:
+                             * - we need to determine how to serialize events in eventstream
+                             * - to specify payload there is an eventpayload trait
+                             * - but what happens if that trait is not specified
+                             * - if there is one field and its a string, blob or struct then we assume that field is event payload
+                             *  (note: this might not be completely correct, spec is vague on that and other sdks do implicit struct around string and blob)
+                             * - if that one field is of any other type then treat parent shape as eventpayload
+                             * - if there is more than one field then parent shape is the payload
+                             */
+                            Shape memberShape = memberEntry.getValue().getShape();
+                            if (memberShape.isString() || 
+                                memberShape.isBlob() || 
+                                memberShape.isStructure()) {
+                                memberEntry.getValue().setEventPayload(true);
+                                shape.setEventPayloadMemberName(memberEntry.getKey());
+                                shape.setEventPayloadType(memberShape.getType());
+                            } else {
+                                if (!shape.getType().equals("structure")) {
+                                    throw new RuntimeException("Event shape should always has \"structure\" type if single member cannot be event payload.");
+                                }
+                                shape.setEventPayloadType(shape.getType());
+                            }
+
                         });
                     } else {
                         throw new RuntimeException("Event shape used in Event Stream should only has one member if it has event payload member.");

tools/code-generation/generator/src/test/java/com/amazonaws/util/awsclientgenerator/transform/C2jModelToGeneratorModelTransformerTest.java

@@ -13,8 +13,10 @@
 import java.util.HashMap;
 import java.util.LinkedList;
 import java.util.Map;
+import com.google.common.collect.ImmutableList;
 
 import static org.junit.Assert.assertTrue;
+import static org.junit.Assert.assertFalse;
 import static org.junit.Assert.assertEquals;
 
 public class C2jModelToGeneratorModelTransformerTest {
@@ -342,7 +344,8 @@ public void testOperationConversion() {
     //     "EventStreamShape":{
     //         "type":"structure",
     //         "members":{
-    //             "EventShape":{"shape":"EventShape"}
+    //             "EventShape":{"shape":"EventShape"},
+    //             "EventEnumShape":{"shape":"EventEnumShape"}
     //         },
     //         "eventstream":true
     //     },
@@ -353,6 +356,17 @@ public void testOperationConversion() {
     //         },
     //         "event":true
     //     },
+    //     "EventEnumShape":{
+    //         "type":"structure",
+    //         "members":{
+    //             "BlobShape":{"shape":"BlobShape"}
+    //         },
+    //         "event":true
+    //     },
+    //     "EnumShape":{
+    //         "type":"string",
+    //          "enum":[VALUE]
+    //     }
     //     "BlobShape":{
     //         "type":"blob"
     //     }
@@ -390,14 +404,35 @@ public void testEventStreamShapeConversion() {
         eventStreamShape.setMembers(new HashMap<>());
         eventStreamShape.getMembers().put("EventShape", eventShapeMember);
 
+        C2jShape eventEnumShape = new C2jShape();
+        eventEnumShape.setType("structure");
+        eventEnumShape.setEvent(true);
+        c2jShapeMap.put("EventEnumShape", eventEnumShape);
+
+        C2jShape enumShape = new C2jShape();
+        enumShape.setType("string");
+        enumShape.setEnums(ImmutableList.of("VALUE"));
+        c2jShapeMap.put("EnumShape", enumShape);
+
+        C2jShapeMember enumShapeMember = new C2jShapeMember();
+        enumShapeMember.setShape("EnumShape");
+
+        eventEnumShape.setMembers(new HashMap<>());
+        eventEnumShape.getMembers().put("EnumShape", enumShapeMember);
+
+        C2jShapeMember eventEnumShapeMember = new C2jShapeMember();
+        eventEnumShapeMember.setShape("EventEnumShape");
+
+        eventStreamShape.getMembers().put("EvenEnumShape", eventEnumShapeMember);
+
         c2jServiceModel.setShapes(c2jShapeMap);
 
         C2jModelToGeneratorModelTransformer c2jModelToGeneratorModelTransformer = new C2jModelToGeneratorModelTransformer(c2jServiceModel, false);
         c2jModelToGeneratorModelTransformer.convertShapes();
         c2jModelToGeneratorModelTransformer.postProcessShapes();
 
         Map<String, Shape> shapes = c2jModelToGeneratorModelTransformer.shapes;
-        assertEquals(3, shapes.size());
+        assertEquals(5, shapes.size());
         assertEquals("EventStreamShape", shapes.get("EventStreamShape").getName());
         assertTrue(shapes.get("EventStreamShape").isEventStream());
         assertEquals("EventShape", shapes.get("EventShape").getName());
@@ -406,10 +441,13 @@ public void testEventStreamShapeConversion() {
         assertEquals("BlobShape", shapes.get("EventShape").getEventPayloadMemberName());
         assertEquals("BlobShape", shapes.get("BlobShape").getName());
         assertEquals("blob", shapes.get("BlobShape").getType());
-        assertEquals(1, shapes.get("EventStreamShape").getMembers().size());
+        assertEquals(2, shapes.get("EventStreamShape").getMembers().size());
         assertEquals("EventShape", shapes.get("EventStreamShape").getMembers().get("EventShape").getShape().getName());
         assertEquals(1, shapes.get("EventShape").getMembers().size());
         assertEquals("BlobShape", shapes.get("EventShape").getMembers().get("BlobShape").getShape().getName());
         assertTrue(shapes.get("EventShape").getMembers().get("BlobShape").isEventPayload());
+
+        assertFalse(shapes.get("EventEnumShape").getMembers().get("EnumShape").isEventPayload());
+        assertEquals("structure", shapes.get("EventEnumShape").getEventPayloadType());
     }
 }