Scope#import with options[:preprocess] throws exception when preprocessed data returns empty

[RonaldKlaus]

Hej!

I have a model person and I want to import all published people. All not yet published people will be rejected from the batch in the preprocess. So it is possible, that all items will be removed from the batch and I am sending an empty batch. That will throw the following exception:

Elasticsearch::Transport::Transport::Errors::BadRequest: [400] {"error":{"root_cause":[{"type":"parse_exception","reason":"Failed to derive xcontent"}],"type":"parse_exception","reason":"Failed to derive xcontent"},"status":400}

I think the behavior should be like import empty scoped data.