Check if file_root is nil.
@@ -87,7 +87,7 @@ func builtinSimpleServerInstanceMethods() []*BuiltInMethodObject {
fileRoot, serveStatic := server.InstanceVariables.get("@file_root")
- if serveStatic {
+ if serveStatic && fileRoot.Class() != t.vm.objectClass.getClassConstant(nullClass) {
fr := fileRoot.(*StringObject).value
currentDir, _ := os.Getwd()
fp := filepath.Join(currentDir, fr)
