Rewrite simple test (only grpc output)

vendor/github.com/golang/protobuf/protoc-gen-go/generator/generator.go

@@ -626,6 +626,7 @@ func (g *Generator) CommandLineParameters(parameter string) {
 			}
 		}
 	}
+
 	if pluginList != "" {
 		// Amend the set of plugins.
 		enabled := make(map[string]bool)
@@ -1180,6 +1181,7 @@ func (g *Generator) generate(file *FileDescriptor) {
 		g.P("const _ = ", g.Pkg["proto"], ".ProtoPackageIsVersion", generatedCodeVersion, " // please upgrade the proto package")
 		g.P()
 	}
+
 	for _, td := range g.file.imp {
 		g.generateImported(td)
 	}
@@ -2076,6 +2078,11 @@ func (g *Generator) generateMessage(message *Descriptor) {
 			star = "*"
 		}
 
+		// In proto3, only generate getters for message fields and oneof fields.
+		if message.proto3() && *field.Type != descriptor.FieldDescriptorProto_TYPE_MESSAGE && !oneof {
+			continue
+		}
+
 		// Only export getter symbols for basic types,
 		// and for messages and enums in the same package.
 		// Groups are not exported.
@@ -2134,11 +2141,7 @@ func (g *Generator) generateMessage(message *Descriptor) {
 			continue
 		}
 		if !oneof {
-			if message.proto3() {
-				g.P("if m != nil {")
-			} else {
-				g.P("if m != nil && m." + fname + " != nil {")
-			}
+			g.P("if m != nil && m." + fname + " != nil {")
 			g.In()
 			g.P("return " + star + "m." + fname)
 			g.Out()
@@ -2556,7 +2559,6 @@ func (g *Generator) generateExtension(ext *ExtensionDescriptor) {
 	g.P("Field: ", field.Number, ",")
 	g.P(`Name: "`, extName, `",`)
 	g.P("Tag: ", tag, ",")
-	g.P(`Filename: "`, g.file.GetName(), `",`)
 
 	g.Out()
 	g.P("}")