Why do some of my core data objects have managedObjectContext set to nil?

I was having problems adding objects to one of my core data objects that has a relationship and after doing some investigating I realized it was because that objects managedObjectContext was nil (0x0). Some more investigating revealed that anytime I created an object of that type, the managedObjectContext was always nil. Every object I create of any other type has the correct managedObjectContext. And no, the object was not deleted, this is immediately after 开发者_开发知识库calling NSEntityDescription:insertNewObjectForEntityForName:inManagedObjectContext

Why would only this particular object be broken? It's also strange that even though the managedObjectContext seems to be nil, it otherwise works correctly (other than the relationship problem). I've tried resetting the simulator several times and I've even regenerated the .h and .m files that core data produces for that object but I can't get it to work. As far as I can tell, there are no errors, the managedObjectContext just never gets set.

I figured it out. I had added a member variable called managedObjectContext, which I instinctively add to most classes in my application since I pretty much always need it. What I didn't realize is that I was overriding the methods of the same name in the parent class NSManagedObject. That's why it was reset to be nil and still worked until I tried to add relationship which queried the managedObjectContext, found it to be nil, and complained.