Correctly handle absence of JavaScript

larsborn commented 2 years ago

The engine variable may be `null. Show a warning and disable the corresponding UI elements.

as0ni commented 2 years ago

I'm encountering this issue with OpenJDK 16. I then read this version of OpenJDK removed the JavaScript engine, so I tried v11 but receive the error Unable to locate script class: HashDB.java. Any help is much appreciated! I'd love to get this working on Ghidra v 10.1.5.

michaeljgoodman commented 2 years ago

This can be reproduced by running a lookup whilst running Ghidra under any of the following:

OpenJDK 64 Bit Version 16.0.1
OpenJDK 64 Bit Version 17.0.1
<OpenJDK any architecture Version 15+>

As documented here the Nashorn script engine has been removed, which was the provider for the "JavaScript" engine type. They've done this as they were having trouble maintaining it and keeping it compatible with ECMAScript standards.

Unfortunately the following code shows that in OpenJDK 15+ there are actually no engine candidates at all.

import java.util.List;

import javax.script.ScriptEngine;
import javax.script.ScriptEngineFactory;
import javax.script.ScriptEngineManager;

public class ListEngines {
  public static void main(String args[]) {
    ScriptEngineManager manager = new ScriptEngineManager();
    List<ScriptEngineFactory> factories = manager.getEngineFactories();
    for (ScriptEngineFactory factory : factories) {
      System.out.println(factory.getEngineName());
      System.out.println(factory.getEngineVersion());
      System.out.println(factory.getLanguageName());
      System.out.println(factory.getLanguageVersion());
      System.out.println(factory.getExtensions());
      System.out.println(factory.getMimeTypes());
      System.out.println(factory.getNames());
    }
  }
}

My current thoughts are:

Add a small indicator to the project/readme to just say "tested with OpenJDK xxxxxx" or just a note to say the plugin doesn't function with OpenJDK 15+
Update code to account for when the engine is null, and perhaps print a message to just say "ScriptEngine is not present in your java instance, transformations not supported"

Have been researching alternatives to the nashorn script engine. it's all a bit messy but will update if I find a simple replacement that can be slotted straight in.

matthw commented 1 year ago

I've moved to jython to handle the transform: https://github.com/OALabs/hashdb-ghidra/compare/main...matthw:hashdb-ghidra:main

OALabs / hashdb-ghidra

Correctly handle absence of JavaScript #7