DataLoaderOptions immutability change

[zsmoore]

Hello all,

We are upgrading to 4.0.0 to get the latest instrumentation changes (thank you this will remove some custom infra we have). However, after the upgrade we have failing tests due to the immutability change.

This is fine as its a major change and we expect to need changes however the immutability change seems like we could go farther here. I agree that we should ditch the mutability and move to immutability however, since this is a major change anyway should we have just deleted the old functionality? Now code that does not have test coverage might break at runtime rather than compile time. Luckily we had test coverage to cover this scenario.

example code

DataLoaderOptions options = DataLoaderOptions.newOptions();
if (maxBatchSize != BatchLoader.UNSET_BATCH_SIZE) {
  options.setMaxBatchSize(maxBatchSize);
}
return options.setCacheMap(cache);

In this case I would prefer if the codebase was broken so we could make the proper fix rather than needing to find it ourselves based on the test results.

Thank you!