Reverse-parses a live relationship (or array-of-relationship) property
definition back into ManagedObjectSchemaRelationshipPropertyFields,
so update can merge only the explicitly-changed overrides onto the
property's actual current state rather than create-time defaults.
Reverse-parses a live relationship (or array-of-relationship) property definition back into ManagedObjectSchemaRelationshipPropertyFields, so update can merge only the explicitly-changed overrides onto the property's actual current state rather than create-time defaults.