Fix merging with message-valued oneof

If messages A and B have the same oneof case, which is a message
type, and we merge B into A, those sub-messages should be merged.

Fixes #3200.

Note that I haven't regenerated all the code, as some of the protos
have been changed, breaking generation.

9 files changed, 30 insertions, 3 deletions

diff --git a/src/google/protobuf/compiler/csharp/csharp_enum_field.cc b/src/google/protobuf/compiler/csharp/csharp_enum_field.cc
index 67c0b596..9ceffa8c 100644
--- a/src/google/protobuf/compiler/csharp/csharp_enum_field.cc
+++ b/src/google/protobuf/compiler/csharp/csharp_enum_field.cc
@@ -89,6 +89,10 @@ EnumOneofFieldGenerator::EnumOneofFieldGenerator(
 EnumOneofFieldGenerator::~EnumOneofFieldGenerator() {
 }
 
+void EnumOneofFieldGenerator::GenerateMergingCode(io::Printer* printer) {
+  printer->Print(variables_, "$property_name$ = other.$property_name$;\n");
+}
+
 void EnumOneofFieldGenerator::GenerateParsingCode(io::Printer* printer) {
   // TODO(jonskeet): What about if we read the default value?
   printer->Print(
diff --git a/src/google/protobuf/compiler/csharp/csharp_enum_field.h b/src/google/protobuf/compiler/csharp/csharp_enum_field.h
index 9b7669ba..631632bc 100644
--- a/src/google/protobuf/compiler/csharp/csharp_enum_field.h
+++ b/src/google/protobuf/compiler/csharp/csharp_enum_field.h
@@ -64,6 +64,7 @@ class EnumOneofFieldGenerator : public PrimitiveOneofFieldGenerator {
                           const Options *options);
   ~EnumOneofFieldGenerator();
 
+  virtual void GenerateMergingCode(io::Printer* printer);
   virtual void GenerateParsingCode(io::Printer* printer);
   virtual void GenerateSerializationCode(io::Printer* printer);
   virtual void GenerateSerializedSizeCode(io::Printer* printer);
diff --git a/src/google/protobuf/compiler/csharp/csharp_message.cc b/src/google/protobuf/compiler/csharp/csharp_message.cc
index 5ef0e4e8..ad9f8a16 100644
--- a/src/google/protobuf/compiler/csharp/csharp_message.cc
+++ b/src/google/protobuf/compiler/csharp/csharp_message.cc
@@ -463,9 +463,12 @@ void MessageGenerator::GenerateMergingMethods(io::Printer* printer) {
       vars["field_property_name"] = GetPropertyName(field);
       printer->Print(
         vars,
-        "case $property_name$OneofCase.$field_property_name$:\n"
-        "  $field_property_name$ = other.$field_property_name$;\n"
-        "  break;\n");
+        "case $property_name$OneofCase.$field_property_name$:\n");
+      printer->Indent();
+      scoped_ptr<FieldGeneratorBase> generator(CreateFieldGeneratorInternal(field));
+      generator->GenerateMergingCode(printer);
+      printer->Print("break;\n");
+      printer->Outdent();
     }
     printer->Outdent();
     printer->Print("}\n\n");
diff --git a/src/google/protobuf/compiler/csharp/csharp_message_field.cc b/src/google/protobuf/compiler/csharp/csharp_message_field.cc
index 438f3102..59b7edfb 100644
--- a/src/google/protobuf/compiler/csharp/csharp_message_field.cc
+++ b/src/google/protobuf/compiler/csharp/csharp_message_field.cc
@@ -171,6 +171,14 @@ void MessageOneofFieldGenerator::GenerateMembers(io::Printer* printer) {
     "}\n");
 }
 
+void MessageOneofFieldGenerator::GenerateMergingCode(io::Printer* printer) {
+  printer->Print(variables_, 
+    "if ($property_name$ == null) {\n"
+    "  $property_name$ = new $type_name$();\n"
+    "}\n"
+    "$property_name$.MergeFrom(other.$property_name$);\n");
+}
+
 void MessageOneofFieldGenerator::GenerateParsingCode(io::Printer* printer) {
   // TODO(jonskeet): We may be able to do better than this
   printer->Print(
diff --git a/src/google/protobuf/compiler/csharp/csharp_message_field.h b/src/google/protobuf/compiler/csharp/csharp_message_field.h
index 7d614756..c41ee88a 100644
--- a/src/google/protobuf/compiler/csharp/csharp_message_field.h
+++ b/src/google/protobuf/compiler/csharp/csharp_message_field.h
@@ -74,6 +74,7 @@ class MessageOneofFieldGenerator : public MessageFieldGenerator {
 
   virtual void GenerateCloningCode(io::Printer* printer);
   virtual void GenerateMembers(io::Printer* printer);
+  virtual void GenerateMergingCode(io::Printer* printer);
   virtual void WriteToString(io::Printer* printer);
   virtual void GenerateParsingCode(io::Printer* printer);
 
diff --git a/src/google/protobuf/compiler/csharp/csharp_primitive_field.cc b/src/google/protobuf/compiler/csharp/csharp_primitive_field.cc
index 169122e6..931adb4a 100644
--- a/src/google/protobuf/compiler/csharp/csharp_primitive_field.cc
+++ b/src/google/protobuf/compiler/csharp/csharp_primitive_field.cc
@@ -196,6 +196,10 @@ void PrimitiveOneofFieldGenerator::GenerateMembers(io::Printer* printer) {
       "}\n");
 }
 
+void PrimitiveOneofFieldGenerator::GenerateMergingCode(io::Printer* printer) {
+  printer->Print(variables_, "$property_name$ = other.$property_name$;\n");
+}
+
 void PrimitiveOneofFieldGenerator::WriteToString(io::Printer* printer) {
   printer->Print(variables_,
     "PrintField(\"$descriptor_name$\", $has_property_check$, $oneof_name$_, writer);\n");
diff --git a/src/google/protobuf/compiler/csharp/csharp_primitive_field.h b/src/google/protobuf/compiler/csharp/csharp_primitive_field.h
index 5f466fc4..ca7b8b3d 100644
--- a/src/google/protobuf/compiler/csharp/csharp_primitive_field.h
+++ b/src/google/protobuf/compiler/csharp/csharp_primitive_field.h
@@ -78,6 +78,7 @@ class PrimitiveOneofFieldGenerator : public PrimitiveFieldGenerator {
 
   virtual void GenerateCloningCode(io::Printer* printer);
   virtual void GenerateMembers(io::Printer* printer);
+  virtual void GenerateMergingCode(io::Printer* printer);
   virtual void WriteToString(io::Printer* printer);
   virtual void GenerateParsingCode(io::Printer* printer);
 
diff --git a/src/google/protobuf/compiler/csharp/csharp_wrapper_field.cc b/src/google/protobuf/compiler/csharp/csharp_wrapper_field.cc
index 797d498e..997969a0 100644
--- a/src/google/protobuf/compiler/csharp/csharp_wrapper_field.cc
+++ b/src/google/protobuf/compiler/csharp/csharp_wrapper_field.cc
@@ -181,6 +181,10 @@ void WrapperOneofFieldGenerator::GenerateMembers(io::Printer* printer) {
     "}\n");
 }
 
+void WrapperOneofFieldGenerator::GenerateMergingCode(io::Printer* printer) {
+  printer->Print(variables_, "$property_name$ = other.$property_name$;\n");
+}
+
 void WrapperOneofFieldGenerator::GenerateParsingCode(io::Printer* printer) {
   printer->Print(
     variables_,
diff --git a/src/google/protobuf/compiler/csharp/csharp_wrapper_field.h b/src/google/protobuf/compiler/csharp/csharp_wrapper_field.h
index 250dfd25..452531fb 100644
--- a/src/google/protobuf/compiler/csharp/csharp_wrapper_field.h
+++ b/src/google/protobuf/compiler/csharp/csharp_wrapper_field.h
@@ -75,6 +75,7 @@ class WrapperOneofFieldGenerator : public WrapperFieldGenerator {
   ~WrapperOneofFieldGenerator();
 
   virtual void GenerateMembers(io::Printer* printer);
+  virtual void GenerateMergingCode(io::Printer* printer);
   virtual void GenerateParsingCode(io::Printer* printer);
   virtual void GenerateSerializationCode(io::Printer* printer);
   virtual void GenerateSerializedSizeCode(io::Printer* printer);