"Core Data could not fulfill a fault" for objects that were not deleted

Question

For a recent update to an app, I am seeing many crash logs with the error that core data could not fulfill a fault. But nowhere in the app (startup, or elsewhere) did I delete the objects whose faults cannot be fulfilled, nor would they have been cascade deleted. How else can this error be happening? And is there a way to catch it and fix it within the live app?

Could it also be if you added but did not properly save the object yet?

Answer 1

It is possible that an object that was not "properly" saved to cause this behaviour.

One way to do that is:

• Insert an object in a child context
  
• obtain a permanent ID for that object
  
• save to the parent context
  
• obtain the object in the parent context
  
• refresh the object in the parent context
  
• access the object in the parent context (fulfil a fault for that object)
  

Edit:

Another way to reach this state in a single context architecture is:

• Insert an object
• obtain a permanent id for the object
• refresh the object
• try and access the object (trigger a fault on the object)

the refresh might be a result of a fetched results controller paging through the data and not necessarily something "visible" in your application.

In addition, there is a CoreData "bug" that not always allows you to catch this exception in a parent-child context architecture, but you can try ...

However, if this is the scenario you encounter, this is not a desired behaviour for your application. you are loosing the new data added to the store.