We've updated the validation for the Cart and Order removeLineItem update actions. When provided, quantity must now be at least 1. Previously, 0 was accepted but produced no change.

Going forward, attempting to use removeLineItem with a quantity of 0 will return a 400 Bad Request error with an InvalidInput code.

The quantity field remains optional. If you omit it, the entire Line Item will be removed, as before.

This change aligns the behavior with the removeLineItem update action for Shopping Lists, ensuring consistency across our APIs.

This is a breaking change; however, the impact is expected to be negligible. Our analysis of API traffic indicates that passing a quantity of 0 is extremely rare. Additionally, since this operation previously had no effect on the Cart, there is no impact on your shoppers' checkout experience.