Question

I am getting intermittent and hard to track CoreData exceptions when trying to delete an object from a UITableView.

There’s a lot of discussion of this on SO, but they’re all specific to a variety of implementations and hard to apply to your own as far as best practice. The tutorials I’ve seen are helpful for setting up, but not so great at teaching you to problem solve your situation.

What are the best methods to debug/problem solve CoreData errors of this type, and what is the expected flow for correct execution?

Errors like this one:

Serious application error. An exception was caught from the delegate
of NSFetchedResultsController during a call to
-controllerDidChangeContent:. Invalid update: invalid number of rows in section 0. The number of rows contained in an existing section
after the update (3) must be equal to the number of rows contained in
that section before the update (3), plus or minus the number of rows
inserted or deleted from that section (0 inserted, 1 deleted) and plus
or minus the number of rows moved into or out of that section (0 moved
in, 0 moved out). with userInfo (null)

Answer 1

The problem actually was caused by a superfluous FetchedResultsController with the UITableView set as its delegate (there’s a discussion here: stackoverflow.com/a/9755379/459116 )