[ggj][codegen] fix: ServiceStubSettings batching request type

src/main/java/com/google/api/generator/gapic/composer/BatchingDescriptorComposer.java

@@ -36,6 +36,7 @@
 import com.google.api.generator.engine.ast.TypeNode;
 import com.google.api.generator.engine.ast.UnaryOperationExpr;
 import com.google.api.generator.engine.ast.ValueExpr;
+import com.google.api.generator.engine.ast.VaporReference;
 import com.google.api.generator.engine.ast.Variable;
 import com.google.api.generator.engine.ast.VariableExpr;
 import com.google.api.generator.gapic.model.Field;
@@ -149,7 +150,14 @@ private static MethodDefinition createGetBatchPartitionKeyMethod(
 
   private static MethodDefinition createGetRequestBuilderMethod(
       Method method, GapicBatchingSettings batchingSettings) {
-    TypeNode builderType = toType(REQUEST_BUILDER_REF, method.inputType());
+    TypeNode builderType =
+        TypeNode.withReference(
+            VaporReference.builder()
+                .setEnclosingClassName(method.inputType().reference().name())
+                .setName("Builder")
+                .setPakkage(method.inputType().reference().pakkage())
+                .build());
+
     VariableExpr builderVarExpr =
         VariableExpr.withVariable(
             Variable.builder().setType(builderType).setName("builder").build());
@@ -220,9 +228,10 @@ private static MethodDefinition createGetRequestBuilderMethod(
                     .build())
             .build();
 
+    TypeNode anonClassType = toType(REQUEST_BUILDER_REF, method.inputType());
     AnonymousClassExpr requestBuilderAnonClassExpr =
         AnonymousClassExpr.builder()
-            .setType(builderType)
+            .setType(anonClassType)
             .setStatements(
                 Arrays.asList(
                     ExprStatement.withExpr(
@@ -237,7 +246,7 @@ private static MethodDefinition createGetRequestBuilderMethod(
     return MethodDefinition.builder()
         .setIsOverride(true)
         .setScope(ScopeNode.PUBLIC)
-        .setReturnType(builderType)
+        .setReturnType(anonClassType)
         .setName("getRequestBuilder")
         .setReturnExpr(requestBuilderAnonClassExpr)
         .build();

src/test/java/com/google/api/generator/gapic/composer/BatchingDescriptorComposerTest.java

@@ -114,7 +114,7 @@ public void batchingDescriptor_hasSubresponseField() {
             "@Override\n",
             "public RequestBuilder<PublishRequest> getRequestBuilder() {\n",
             "return new RequestBuilder<PublishRequest>() {\n",
-            "private RequestBuilder<PublishRequest> builder;\n",
+            "private PublishRequest.Builder builder;\n",
             "@Override\n",
             "public void appendRequest(PublishRequest request) {\n",
             "if (Objects.isNull(builder)) {\n",
@@ -234,7 +234,7 @@ public void batchingDescriptor_noSubresponseField() {
             "@Override\n",
             "public RequestBuilder<WriteLogEntriesRequest> getRequestBuilder() {\n",
             "return new RequestBuilder<WriteLogEntriesRequest>() {\n",
-            "private RequestBuilder<WriteLogEntriesRequest> builder;\n",
+            "private WriteLogEntriesRequest.Builder builder;\n",
             "@Override\n",
             "public void appendRequest(WriteLogEntriesRequest request) {\n",
             "if (Objects.isNull(builder)) {\n",

src/test/java/com/google/api/generator/gapic/composer/ServiceStubSettingsClassComposerTest.java

@@ -1063,7 +1063,7 @@ private static List<Service> parseServices(
           + "            @Override\n"
           + "            public RequestBuilder<WriteLogEntriesRequest> getRequestBuilder() {\n"
           + "              return new RequestBuilder<WriteLogEntriesRequest>() {\n"
-          + "                private RequestBuilder<WriteLogEntriesRequest> builder;\n"
+          + "                private WriteLogEntriesRequest.Builder builder;\n"
           + "\n"
           + "                @Override\n"
           + "                public void appendRequest(WriteLogEntriesRequest request) {\n"
@@ -1793,7 +1793,7 @@ private static List<Service> parseServices(
           + "        @Override\n"
           + "        public RequestBuilder<PublishRequest> getRequestBuilder() {\n"
           + "          return new RequestBuilder<PublishRequest>() {\n"
-          + "            private RequestBuilder<PublishRequest> builder;\n"
+          + "            private PublishRequest.Builder builder;\n"
           + "\n"
           + "            @Override\n"
           + "            public void appendRequest(PublishRequest request) {\n"