Merge pull request #112 from kzys/skip-empty-go-file

Only generate a Go file if the file has some services

cmd/protoc-gen-go-ttrpc/generator.go

@@ -91,6 +91,11 @@ func newGenerator(out *protogen.GeneratedFile) *generator {
 }
 
 func generate(plugin *protogen.Plugin, input *protogen.File) error {
+	if len(input.Services) == 0 {
+		// Only generate a Go file if the file has some services.
+		return nil
+	}
+
 	file := plugin.NewGeneratedFile(input.GeneratedFilenamePrefix+"_ttrpc.pb.go", input.GoImportPath)
 	file.P("// Code generated by protoc-gen-go-ttrpc. DO NOT EDIT.")
 	file.P("// source: ", input.Desc.Path())