I'm trying to plug into order transitions in order to send my order to a custom fulfillment system.
I have a transition called "send_to_fulfillment", and order states "reviewing" and "sent_to_fulfillment".
I'm hooking into the commerce_order.send_to_fulfillment.pre_transition event. What I can't figure out is how to cancel the transition if the process fails. I can certainly just throw an exception and let the site die, but I'd prefer to be able to elegantly stop the transition and inform the user of the error.
Any tips? I've tried WorkflowTransitionEvent::stopPropagation which didn't do it, and I can't seem to find it documented anywhere.