303572 - Need access to underlying RhinoException in rethrown error objects

Status: RESOLVED FIXED

(Rhino Graveyard :: Core, enhancement)

Description

[Attila Szegedi]

User-Agent:       Opera/8.01 (Windows NT 5.0; U; en)
Build Identifier: 

There's a situation where scripts catch and then selectively rethrow exceptions:

try
{
    ...
}
catch(e)
{
    if(e instanceof JavaException && e.javaException.class.name == "com.foo.
ValidationException")
    {
        ...
    }
    else
    {
        throw e;
    }
}

Now, when the thrown exception is some internal Rhino exception, i.e. TypeError, 
its stack trace will be lost after the throw -- the Java code invoking the 
script will ultimately get a JavaScriptException with the error object 
constructed in the catch clause. I'd suggest that similar to the nonstandard 
"javaException" field, the error object should also have an also nonstandard  
"rhinoException" field for these exceptions. Then the Java code invoking the 
script could do the following to ensure it logs the root cause exception 
regardless of how many times it is caught and rethrown in the script:

Throwable terminationCause;
try
{
    script.exec(...);
    terminationCause = null;
}
catch(JavaScriptException e)
{
    terminationCause = e;
    Object val = e.getValue();
    if(val instanceof Scriptable)
    {
        Object njo = ScriptableObject.getProperty(((Scriptable)val), 
                "rhinoException");
        if(njo instanceof NativeJavaObject)
        {
            val = njo;
        }
        else
        {
            njo = ScriptableObject.getProperty(((Scriptable)val), 
                "javaException");
            if(njo instanceof NativeJavaObject)
            {
                val = njo;
            }
        }
    }
    if(val instanceof NativeJavaObject)
    {
        Object t = ((NativeJavaObject)val).unwrap();
        while(t instanceof InvocationTargetException)
        {
            t = ((InvocationTargetException)t).getCause();
        }
        if(t instanceof Throwable)
        {
            terminationCause = (Throwable)t;
        }
    }
}
catch(Throwable t)
{
    terminationCause = t;
}
if(terminationCause != null)
{
    logger.error("Script failed", terminationCause);
}

I'll attach a patch

Reproducible: Always

Steps to Reproduce:

Comment 1

[Attila Szegedi]

Attachment: The patch that implements the feature

I've attached the patch that implements the feature. If nobody objects until
Monday, I'll commit it then.

Comment 2

[Attila Szegedi]

Committed the patch.