Question

I found that originalPayload does not do the same as message.originalPayload in groovy expressions. That is, the following transformers do not do the same thing:

with originalPayload:

<expression-transformer evaluator="groovy" expression="originalPayload" />

with message.originalPayload:

<expression-transformer evaluator="groovy" expression="message.originalPayload" />

The following mule configuration and test case can be used to reproduce the issue:

<mule ...>
    <flow name="test">
        <vm:inbound-endpoint name="test.Name" path="test.Path"
            exchange-pattern="request-response" />

        <expression-transformer evaluator="string" expression="bar" />

        <expression-transformer evaluator="groovy" expression="originalPayload" />
        <!-- or alternatively -->
        <!-- <expression-transformer evaluator="groovy" expression="message.originalPayload" /> -->
    </flow>
</mule>

The test case can be:

@Test
public void transformers() throws MuleException {
    final MuleClient client = muleContext.getClient();
    final MuleMessage reply = client.send("vm://test.Path", 1, null, RECEIVE_TIMEOUT);
    assertEquals(1, reply.getPayload());
}

The alternative with message.originalPayload works as expected. The one with originalPayload does not and the following exception is shown in the logs:

Exception stack is:
1. Expression Evaluator "groovy" with expression "originalPayload" returned null 
but a value was required. (org.mule.api.expression.RequiredValue Exception)

What could I be doing wrong?

Thanks.

Answer 1

The problem is that expression-transformer and scripting:transformer use a different set of bindings than the one used by a scripting:component, and this because they call a different method in org.mule.module.scripting.component.Scriptable.

Moreover, when originalPayload gets bound, it is with the wrong value:

bindings.put("originalPayload", event.getMessage().getPayload());

Hence: MULE-6215