Allow errors as event stream output members

.changes/next-release/bugfix-AWSSDKforJavav2-52218bd.json

@@ -0,0 +1,6 @@
+{
+    "type": "bugfix",
+    "category": "AWS SDK for Java v2",
+    "contributor": "",
+    "description": "Update codegen to allow errors as event stream output members"
+}

codegen/src/main/java/software/amazon/awssdk/codegen/RemoveUnusedShapes.java

@@ -26,6 +26,7 @@
 import software.amazon.awssdk.codegen.model.intermediate.OperationModel;
 import software.amazon.awssdk.codegen.model.intermediate.ReturnTypeModel;
 import software.amazon.awssdk.codegen.model.intermediate.ShapeModel;
+import software.amazon.awssdk.codegen.model.intermediate.ShapeType;
 import software.amazon.awssdk.codegen.model.intermediate.VariableModel;
 
 /**
@@ -94,7 +95,7 @@ private static void addShapeAndMembers(String shapeName,
 
             if (members != null) {
                 for (MemberModel member : members) {
-                    List<String> memberShapes = resolveMemberShapes(member);
+                    List<String> memberShapes = resolveMemberShapes(member, in);
                     if (memberShapes == null) {
                         continue;
                     }
@@ -111,24 +112,31 @@ private static void addShapeAndMembers(String shapeName,
      * both the key shape and the value shape of the map will be resolved, so that the
      * returning list could have more than one elements.
      */
-    private static List<String> resolveMemberShapes(MemberModel member) {
+    private static List<String> resolveMemberShapes(MemberModel member, Map<String, ShapeModel> modelShapes) {
 
         if (member == null) {
             return new LinkedList<>();
         }
         if (member.getEnumType() != null) {
             return Collections.singletonList(member.getEnumType());
         } else if (member.isList()) {
-            return resolveMemberShapes(member.getListModel().getListMemberModel());
+            return resolveMemberShapes(member.getListModel().getListMemberModel(), modelShapes);
         } else if (member.isMap()) {
             List<String> memberShapes = new LinkedList<>();
-            memberShapes.addAll(resolveMemberShapes(member.getMapModel().getKeyModel()));
-            memberShapes.addAll(resolveMemberShapes(member.getMapModel().getValueModel()));
+            memberShapes.addAll(resolveMemberShapes(member.getMapModel().getKeyModel(), modelShapes));
+            memberShapes.addAll(resolveMemberShapes(member.getMapModel().getValueModel(), modelShapes));
             return memberShapes;
         } else if (member.isSimple()) {
             // member is scalar, do nothing
             return new LinkedList<>();
         } else {
+            // Exceptions have suffix appended, find shape by C2J name
+            for (ShapeModel shape : modelShapes.values()) {
+                if (shape.getShapeType().equals(ShapeType.Exception) && member.getC2jShape().equals(shape.getC2jName())) {
+                    return Collections.singletonList(shape.getShapeName());
+                }
+            }
+
             // member is a structure.
             return Collections.singletonList(member.getVariable().getSimpleType());
         }

codegen/src/test/resources/software/amazon/awssdk/codegen/poet/eventstream/service-2.json

@@ -68,6 +68,9 @@
       "members": {
         "EventStream": {
           "shape": "EventStream"
+        },
+        "EventStreamError": {
+          "shape": "EventStreamError"
         }
       }
     },
@@ -127,6 +130,16 @@
       },
       "event": true
     },
+    "EventStreamError": {
+      "type": "structure",
+      "members": {
+        "message": {
+          "shape": "String"
+        }
+      },
+      "exception": true,
+      "fault": true
+    },
     "EventStreamOperationWithOnlyInputRequest": {
       "type": "structure",
       "required": [