Debugging Declarative Mutation Directives

If you see an error similar to:

RelayFBHandlerProvider: No handler defined for `deleteRecord`. [Caught in: An uncaught error was thrown inside `RelayObservable`.]

or

RelayModernEnvironment: Expected a handler to be provided for handle `deleteRecord`.

This probably means that you are using a Relay environment to which a handlerProvider is passed. However, the handler provider does not know how to accept the handles "deleteRecord", "appendEdge" or "prependEdge". If this is the case, you should return MutationHandlers.DeleteRecordHandler, MutationHandlers.AppendEdgeHandler, or MutationHandlers.PrependEdgeHandler respectively (these can be imported from relay-runtime).