Issue #3436984: Prevent computeValue loop
I some scenarios, ensureComputedValue() was being called while computeValue() was still computing the value via a call to $renderer->executeInRenderContext. This merge adds a flag to prevent computing if already in the process of computing.
- /src/Plugin/Field/MetatagEntityFieldItemList.php
- /src/TypedData/ComputedItemListTrait.php