Referenced entries not updated correctly in registry

[clemens]

The current implementation suffers from issues because the registry values aren't updated correctly.

Sample use case:

• Create a customer with a credit card using Braintree::Customer.create
• Create a subscription with a discount using Braintree::Subscription.create with the credit card from above.
• Update the discount using Braintree::Subscription.update with appropriate values for discounts: { update: [...] }.
• Check the discount via the customer (Braintree::Customer.find(...).credit_cards[0].subscriptions[0].discounts[0]) or the credit card (Braintree::CreditCard.find(...).subscriptions[0].discounts[0]) => it still has the old values. Check the subscription directly (Braintree::Subscription.find(...).discounts[0]`) => it has the new values.

Is there any desire to fix this? I'd imagine it's not too easy since it would probably be necessary to come up with an entirely new concept for the registry (e.g. using a database or building something like an identity map).