1 files changed, 18 insertions, 30 deletions
diff --git a/src/google/protobuf/compiler/java/java_message_builder.cc b/src/google/protobuf/compiler/java/java_message_builder.cc
index f5643abc..5368c1df 100644
--- a/src/google/protobuf/compiler/java/java_message_builder.cc
+++ b/src/google/protobuf/compiler/java/java_message_builder.cc
@@ -54,8 +54,9 @@
 #include <google/protobuf/io/printer.h>
 #include <google/protobuf/descriptor.pb.h>
 #include <google/protobuf/wire_format.h>
-#include <google/protobuf/stubs/strutil.h>
 #include <google/protobuf/stubs/substitute.h>
+#include <google/protobuf/stubs/strutil.h>
+
 
 namespace google {
 namespace protobuf {
@@ -171,36 +172,25 @@ Generate(io::Printer* printer) {
                      .GenerateBuilderMembers(printer);
   }
 
-  if (!PreserveUnknownFields(descriptor_)) {
-    printer->Print(
-      "public final Builder setUnknownFields(\n"
-      "    final com.google.protobuf.UnknownFieldSet unknownFields) {\n"
-      "  return this;\n"
-      "}\n"
-      "\n"
-      "public final Builder mergeUnknownFields(\n"
-      "    final com.google.protobuf.UnknownFieldSet unknownFields) {\n"
-      "  return this;\n"
-      "}\n"
-      "\n");
-  } else {
+  bool is_proto3 =
+      descriptor_->file()->syntax() == FileDescriptor::SYNTAX_PROTO3;
     // Override methods declared in GeneratedMessage to return the concrete
     // generated type so callsites won't depend on GeneratedMessage. This
     // is needed to keep binary compatibility when we change generated code
     // to subclass a different GeneratedMessage class (e.g., in v3.0.0 release
     // we changed all generated code to subclass GeneratedMessageV3).
-    printer->Print(
-      "public final Builder setUnknownFields(\n"
-      "    final com.google.protobuf.UnknownFieldSet unknownFields) {\n"
-      "  return super.setUnknownFields(unknownFields);\n"
-      "}\n"
-      "\n"
-      "public final Builder mergeUnknownFields(\n"
-      "    final com.google.protobuf.UnknownFieldSet unknownFields) {\n"
-      "  return super.mergeUnknownFields(unknownFields);\n"
-      "}\n"
-      "\n");
-  }
+  printer->Print(
+    "public final Builder setUnknownFields(\n"
+    "    final com.google.protobuf.UnknownFieldSet unknownFields) {\n"
+    "  return super.setUnknownFields$suffix$(unknownFields);\n"
+    "}\n"
+    "\n"
+    "public final Builder mergeUnknownFields(\n"
+    "    final com.google.protobuf.UnknownFieldSet unknownFields) {\n"
+    "  return super.mergeUnknownFields(unknownFields);\n"
+    "}\n"
+    "\n",
+    "suffix", is_proto3 ? "Proto3" : "");
 
   printer->Print(
     "\n"
@@ -594,10 +584,8 @@ GenerateCommonBuilderMethods(io::Printer* printer) {
         "  this.mergeExtensionFields(other);\n");
     }
 
-    if (PreserveUnknownFields(descriptor_)) {
-      printer->Print(
-        "  this.mergeUnknownFields(other.unknownFields);\n");
-    }
+    printer->Print(
+      "  this.mergeUnknownFields(other.unknownFields);\n");
 
     printer->Print(
       "  onChanged();\n");