codegen: Updates SDK's generated serde for unmodeled operation input/…

…output (#1050)

Updates the SDK's generate serializers and deserializers for operations without modeled input and output types. This fixes #1047 where the SDK was attempting to deserialize a response from a service for an operation that had no modeled output. The SDK should of ignored the response instead of trying to deserialize it.

This update will not attempt to serialize inputs for operations without modeled inputs, and will discard responses from services of operations with unmodeled outputs.

Related to aws/smithy-go#261
Fixes #1047

codegen/smithy-aws-go-codegen/src/main/java/software/amazon/smithy/aws/go/codegen/AwsQuery.java

@@ -68,9 +68,6 @@ protected void serializeInputDocument(GenerationContext context, OperationShape
             writer.openBlock("if err := $L(input, bodyEncoder.Value); err != nil {", "}", functionName, () -> {
                 writer.write("return out, metadata, &smithy.SerializationError{Err: err}");
             }).write("");
-        } else {
-            writer.write("_ = input");
-            writer.write("");
         }
 
         writer.write("err = bodyEncoder.Encode()");

codegen/smithy-aws-go-codegen/src/main/java/software/amazon/smithy/aws/go/codegen/JsonRpcProtocolGenerator.java

@@ -67,8 +67,6 @@ protected void serializeInputDocument(GenerationContext context, OperationShape
 
         // If there are no members then there's nothing to serialize
         if (input.members().size() == 0) {
-            // Prevent warnings caused by input not being used
-            writer.write("_ = input");
             return;
         }
 

codegen/smithy-aws-go-codegen/src/main/java/software/amazon/smithy/aws/go/codegen/XmlProtocolUtils.java

@@ -237,7 +237,9 @@ private static String getSerializedXMLShapeName(ProtocolGenerator.GenerationCont
         Optional<SyntheticClone> clone = shape.getTrait(SyntheticClone.class);
         if (clone.isPresent()) {
             SyntheticClone cl = clone.get();
-            shapeName = cl.getArchetype().getName();
+            if (cl.getArchetype().isPresent()) {
+                shapeName = cl.getArchetype().get().getName();
+            }
         }
 
         // check if shape is member shape