Store.getOrComputeIfAbsent() shadows values from parent store

[sbrannen]

Status Quo

In direct contrast to the get() methods in ExtensionContext.Store, the getOrComputeIfAbsent() methods in ExtensionContext.Store only perform a local lookup before invoking the supplied Function<K, V> defaultCreator. Consequently, even if a value has been stored under the supplied key in the parent Store, the getOrComputeIfAbsent() methods will always create a new default value and store it locally, thereby shadowing the desired, existing value from the parent.

Deliverables

• Ensure that getOrComputeIfAbsent() methods in ExtensionContext.Store do not shadow values from parent stores.