@CanIgnoreReturnValue for blocking stub methods returning Empty

grpc · Jun 15, 2024 · 56505b0 · 56505b0
1 parent 889893d
commit 56505b0
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Showing 2 changed files with 12 additions and 1 deletion.
diff --git a/compiler/src/java_plugin/cpp/java_generator.cpp b/compiler/src/java_plugin/cpp/java_generator.cpp
@@ -661,7 +661,8 @@ static void PrintStub(
  for (int i = 0; i < service->method_count(); ++i) {
  const MethodDescriptor* method = service->method(i);
  (*vars)["input_type"] = MessageFullJavaName(method->input_type());
- (*vars)["output_type"] = MessageFullJavaName(method->output_type());
+ std::string output_type = MessageFullJavaName(method->output_type());
+ (*vars)["output_type"] = output_type;
  (*vars)["lower_method_name"] = LowerMethodName(method);
  (*vars)["method_method_name"] = MethodPropertiesGetterName(method);
  bool client_streaming = method->client_streaming();
@@ -682,6 +683,11 @@ static void PrintStub(
  // TODO(nmittler): Replace with WriteMethodDocComment once included by the protobuf distro.
  GrpcWriteMethodDocComment(p, method);
 
+ if (call_type == BLOCKING_CALL &&
+ !server_streaming &&
+ output_type == "com.google.protobuf.Empty") {
+ p->Print(*vars, "@$CanIgnoreReturnValue$\n");
+ }
  if (method->options().deprecated()) {
  p->Print(*vars, "@$Deprecated$\n");
  }
@@ -1261,6 +1267,7 @@ void GenerateService(const ServiceDescriptor* service,
  vars["GrpcGenerated"] = "io.grpc.stub.annotations.GrpcGenerated";
  vars["ListenableFuture"] =
  "com.google.common.util.concurrent.ListenableFuture";
+ vars["CanIgnoreReturnValue"] = "com.google.errorprone.annotations.CanIgnoreReturnValue";
 
  Printer printer(out, '$');
  std::string package_name = ServiceJavaPackage(service->file());

diff --git a/compiler/src/test/proto/grpc/testing/compiler/test.proto b/compiler/src/test/proto/grpc/testing/compiler/test.proto
@@ -20,6 +20,8 @@ package grpc.testing.compiler;
 
 option java_package = "io.grpc.testing.compiler";
 
+import "google/protobuf/empty.proto";
+
 message SimpleRequest {
 }
 
@@ -80,6 +82,8 @@ service TestService {
  rpc IdempotentCall(SimpleRequest) returns (SimpleResponse) {
  option idempotency_level = IDEMPOTENT;
  }
+
+ rpc UnaryCallWithoutResult(SimpleRequest) returns (google.protobuf.Empty);
 }
 
 // Test service that has been deprecated and should generate with Java's @Deprecated annotation