Fix protobuf copy move

phaser/compiler/gen.cc

@@ -228,6 +228,7 @@ Generator::Generator(const google::protobuf::FileDescriptor* file,
 void Generator::GenerateHeaders(std::ostream& os, std::string* error) {
   os << "#pragma once\n";
   os << "#include \"phaser/runtime/runtime.h\"\n";
+  os << "#include <new>\n";
   if (frontend_style_ == FrontendStyle::kRos && UsesRos1Intrinsic(file_)) {
     os << "#include \"phaser/runtime/ros.h\"\n";
   }

phaser/compiler/message_gen.cc

@@ -910,6 +910,8 @@ absl::Status MessageGenerator::GenerateHeader(std::ostream& os) {
   if (IsRosFrontend()) {
     GenerateRosOwnerCopyMove(os, true);
     GeneratePublicFieldDeclarations(os);
+  } else {
+    GenerateProtobufCopyMove(os, true);
   }
 
   // Generate protobuf accessors.
@@ -1030,6 +1032,30 @@ void MessageGenerator::GenerateRosOwnerCopyMove(std::ostream& os, bool decl) {
   os << "}\n\n";
 }
 
+void MessageGenerator::GenerateProtobufCopyMove(std::ostream& os, bool decl) {
+  if (IsRosFrontend()) {
+    return;
+  }
+  const std::string name = MessageName(message_);
+  if (decl) {
+    os << "  " << name << "(const " << name << "& other) = default;\n";
+    os << "  " << name << "& operator=(const " << name
+       << "& other) = default;\n";
+    os << "  " << name << "(" << name << "&& other) noexcept = default;\n";
+    os << "  " << name << "& operator=(" << name << "&& other) noexcept;\n\n";
+    return;
+  }
+
+  os << name << "& " << name << "::operator=(" << name
+     << "&& other) noexcept {\n";
+  os << "  if (this != &other) {\n";
+  os << "    this->~" << name << "();\n";
+  os << "    new (this) " << name << "(std::move(other));\n";
+  os << "  }\n";
+  os << "  return *this;\n";
+  os << "}\n\n";
+}
+
 void MessageGenerator::GenerateSource(std::ostream& os) {
   for (const auto& nested : nested_message_gens_) {
     nested->GenerateSource(os);
@@ -1038,6 +1064,8 @@ void MessageGenerator::GenerateSource(std::ostream& os) {
   GenerateConstructors(os, false);
   if (IsRosFrontend()) {
     GenerateRosOwnerCopyMove(os, false);
+  } else {
+    GenerateProtobufCopyMove(os, false);
   }
 
   // Generate creators.

phaser/compiler/message_gen.h

@@ -101,6 +101,7 @@ class MessageGenerator {
   void GeneratePublicFieldDeclarations(std::ostream& os);
   void GenerateRosOneofTypes(std::ostream& os);
   void GenerateRosOwnerCopyMove(std::ostream& os, bool decl);
+  void GenerateProtobufCopyMove(std::ostream& os, bool decl);
   void GenerateRosSyncToPayload(std::ostream& os);
   void GenerateProtobufAccessors(std::ostream& os);
   void GenerateFieldProtobufAccessors(std::ostream& os);

phaser/stress_test.cc

@@ -61,6 +61,22 @@ TEST(StressTest, DynamicExplicitBufferExpansion) {
   EXPECT_EQ("expand-me", msg.s());
 }
 
+TEST(StressTest, MoveAssignmentReplacesMessageStorage) {
+  TestMessage destination;
+  destination.set_x(1);
+  destination.set_s("destination");
+
+  TestMessage source = TestMessage::CreateDynamicMutable(512);
+  source.set_x(42);
+  source.set_s("source");
+
+  destination = std::move(source);
+
+  EXPECT_EQ(destination.x(), 42);
+  EXPECT_EQ(destination.s(), "source");
+  EXPECT_FALSE(source.IsBound());
+}
+
 TEST(StressTest, AllocFailsAtStart) {
   auto status = ::phaser::NewDynamicBuffer(
       1024, ::phaser::test::AllocUntilLimit(0),