FIx nested InvocationTargetException

[bentsherman]

Close #3418

When a method invoked via reflection throws an exception, the exception is wrapped in an InvocationTargetException. BaseScript already has a catch block to unwrap this exception, but for some reason there are some cases where the exception is wrapped twice, such as the linked issue.

I tried burying the user exception in more function calls and workflow calls, but it was only ever wrapped once or twice. So it does not seem to depend on the call depth, but I can't explain why it is wrapped sometimes once and sometimes twice. So I just check both cases.

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[bentsherman]

A more general solution...

def err = e
while( err instanceof InvocationTargetException )
    err = err.cause

[pditommaso]

yeah, but it looks that it would make more sense

def err = e
while( err instanceof InvocationTargetException )
    err = err.target

[bentsherman]

According to the docs, targetException is the same as cause, it's just older from before cause became the standard for all exceptions. That's why I updated the other occurrence in TaskProcessor.

[pditommaso]

Not according to the reality .. oops, screenshot was broken.

[bentsherman]

Looking at the screenshot, my guess is that getTargetException() and getCause() both map to target. The docs say they are identical, so I don't really care which one we use.

[pditommaso]

Good point

    public Throwable getTargetException() {
        return target;
    }

    /**
     * Returns the cause of this exception (the thrown target exception,
     * which may be {@code null}).
     *
     * @return  the cause of this exception.
     * @since   1.4
     */
    @Override
    public Throwable getCause() {
        return target;
    }