Ben Roling reported this on the cdk-dev list.
First, I tried to write the data without doing a DatasetRepository.update() to give the dataset the new schema. I didn't know if I would be allowed to write data with a newer schema that is still compatible to be read by the dataset's defined schema.
I added favoriteFood in user.avsc:
When I attempted to put an instance of this new User model, it failed with a NullPointerException:
I'm not sure whether you would expect writing data that doesn't exactly match the schema of the dataset to be allowed, but even if not it seems an NPE is a bug?