Program: 151793
Project: 151793
Buggy source:
protected String evaluateVar(String varname){
  if (varname == null || varname.equals("String_Node_Str")) {
    return "String_Node_Str";
  }
  if (varname.charAt(0) == REFERENCEOP) {
    char c=varname.charAt(1);
    if (c == LOCALSCOPE || c == PLAYERSCOPE || c == GLOBALSCOPE) {
      return varname.substring(1);
    }
 else {
      return null;
    }
  }
 else   if (varname.charAt(0) == LOCALSCOPE) {
    String loc=varname.substring(1);
    if (loc.equals("String_Node_Str")) {
      return player != null ? player.getName() : "String_Node_Str";
    }
 else     if (loc.equals("String_Node_Str")) {
      return event.name;
    }
 else     if (loc.equals("String_Node_Str")) {
      return "String_Node_Str" + event.name;
    }
 else     if (loc.equals("String_Node_Str")) {
      return event.value;
    }
 else     if (loc.equals("String_Node_Str")) {
      return String.valueOf(event.coordinate);
    }
 else     if (loc.equals("String_Node_Str")) {
      return threadstack.size() == 0 ? "String_Node_Str" : threadstack.remove(0);
    }
 else     if (loc.equals("String_Node_Str")) {
      return threadstack.size() == 0 ? "String_Node_Str" : threadstack.get(0);
    }
 else     if (eventHost.colors.containsKey(loc)) {
      return "String_Node_Str" + eventHost.colors.get(loc);
    }
 else {
      String v=vars.get(loc);
      if (v == null) {
        vars.put(loc,"String_Node_Str");
        v="String_Node_Str";
      }
      return String.valueOf(v);
    }
  }
 else   if (varname.charAt(0) == PLAYERSCOPE) {
    return String.valueOf(player.vars.get(varname.substring(1)));
  }
 else   if (varname.charAt(0) == GLOBALSCOPE) {
    eventHost.globalVarLock.lock();
    Event ev=eventHost.findEvent(varname.substring(1));
    if (ev == null) {
      notifyError("String_Node_Str");
      eventHost.globalVarLock.unlock();
      return "String_Node_Str";
    }
 else {
      eventHost.globalVarLock.unlock();
      return String.valueOf(ev.value);
    }
  }
  return null;
}

Fixed version (ground truth):
protected String evaluateVar(String varname){
  if (varname == null || varname.equals("String_Node_Str")) {
    return "String_Node_Str";
  }
  if (varname.charAt(0) == REFERENCEOP) {
    char c=varname.charAt(1);
    if (c == LOCALSCOPE || c == PLAYERSCOPE || c == GLOBALSCOPE) {
      return varname.substring(1);
    }
 else {
      return null;
    }
  }
 else   if (varname.charAt(0) == LOCALSCOPE) {
    String loc=varname.substring(1);
    if (loc.equals("String_Node_Str")) {
      return player != null ? player.getName() : "String_Node_Str";
    }
 else     if (loc.equals("String_Node_Str")) {
      return event.name;
    }
 else     if (loc.equals("String_Node_Str")) {
      return "String_Node_Str" + event.name;
    }
 else     if (loc.equals("String_Node_Str")) {
      return eventHost.globals.get(event.name);
    }
 else     if (loc.equals("String_Node_Str")) {
      return String.valueOf(event.coordinate);
    }
 else     if (loc.equals("String_Node_Str")) {
      return threadstack.size() == 0 ? "String_Node_Str" : threadstack.remove(0);
    }
 else     if (loc.equals("String_Node_Str")) {
      return threadstack.size() == 0 ? "String_Node_Str" : threadstack.get(0);
    }
 else     if (eventHost.colors.containsKey(loc)) {
      return "String_Node_Str" + eventHost.colors.get(loc);
    }
 else {
      String v=vars.get(loc);
      if (v == null) {
        vars.put(loc,"String_Node_Str");
        v="String_Node_Str";
      }
      return String.valueOf(v);
    }
  }
 else   if (varname.charAt(0) == PLAYERSCOPE) {
    return String.valueOf(player.vars.get(varname.substring(1)));
  }
 else   if (varname.charAt(0) == GLOBALSCOPE) {
    String name=varname.substring(1);
    if (eventHost.globals.containsKey(name)) {
      String ret=eventHost.globals.get(name);
      return ret;
    }
 else {
      notifyError("String_Node_Str" + name + "String_Node_Str");
      return "String_Node_Str";
    }
  }
  return null;
}