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    <p><code>NSFetchedResultsController</code> gets terribly confused if you use an <code>NSFetchRequest</code> when preparing your cell in response to <code>tableView:cellForRowAtIndexPath:</code>. If you don't execute a <code>NSFetchRequest</code>, all is well. However, if you do, it triggers <code>NSFetchedResultsController</code> to perform further change notifications, which does bad things to <code>UITableView</code>.</p> <p>The workaround for this is to set <code>includesPendingChanges = NO</code> on your NSFetchRequest.</p> <p>I have opened a radar issue about this -- problem id <code>14048101</code> -- with a detailed example and sample app. This bug reproduces on iOS 5.1, 6.0, and 6.1.</p> <p>In my sample app, I added logging to Xcode's CoreData template to log enter/leave of <code>NSFetchedResultsController</code> delegate methods. When I insert + delete objects on the network context, the logging shows:</p> <p>01: => (before) mergeChangesFromContextDidSaveNotification 02: => (enter) controllerWillChangeContent count=4 03: &lt;= (leave) controllerWillChangeContent count=4 04: didChangeObject type=1 indexPath=(null) newIndexPath= 2 indexes [0, 0] 05: => (enter) controllerDidChangeContent count=5</p> <p>At this point, all is good. <code>controllerDidChangeContent:</code> has been called to process the 1 insert, which calls <code>[tableView endUpdates]</code>, which calls <code>tableView:cellForRowAtIndexPath:</code>, which calls <code>configureCell:atIndexPath:</code>.</p> <p>06: => (enter) configure cell at row 0</p> <p>At this point, <code>configureCell:atIndexPath:</code> creates an <code>NSFetchRequest</code> and calls <code>[self.managedObjectContext executeFetchRequest:error:]</code> -- here begins the badness. Executing this fetch request triggers the processing of the remaining changes in the context (1 delete and 3 updates) before processing of the insert has finished (we entered <code>controllerDidChangeContent:</code> on line #05 and don't leave until line #16).</p> <p>07: => (enter) controllerWillChangeContent count=5 08: &lt;= (leave) controllerWillChangeContent count=5 09: didChangeObject type=2 indexPath= 2 indexes [0, 4] newIndexPath=(null) 10: didChangeObject type=4 indexPath= 2 indexes [0, 2] newIndexPath=(null) 11: didChangeObject type=4 indexPath= 2 indexes [0, 1] newIndexPath=(null) 12: didChangeObject type=4 indexPath= 2 indexes [0, 3] newIndexPath=(null) 13: => (enter) controllerDidChangeContent count=4</p> <p>At this point, the framework is making a re-entrant call to<code>controllerDidChangeContent:</code>.</p> <p>14: &lt;= (leave) controllerDidChangeContent count=4 15: &lt;= (leave) configure cell at row 0 16: &lt;= (leave) controllerDidChangeContent count=4 17: &lt;= (after) mergeChangesFromContextDidSaveNotification</p> <p>At this point, you can see in the UI that: (1) a new cell has been added, (2) 3 cells were updated, and (3) the deleted cell is still visible, which is wrong.</p> <p>After further action in the UI, I typically get an <code>Assertion failure</code> or message sent to an invalid object exception.</p> <p>My sample app is available at <a href="https://github.com/peymano/CoreDataFetchedResultsController" rel="noreferrer">https://github.com/peymano/CoreDataFetchedResultsController</a></p>
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    1. POAssertion failure in -[UITableView _endCellAnimationsWithContext:] with NSFetchedResultsController
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    1. POAssertion failure in -[UITableView _endCellAnimationsWithContext:] with NSFetchedResultsController
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    1. COThis is it! I arrived at this answer after looking at many many different questions that relate to this error. This is the only one that helped provide understanding of what's going on with my issue. If any of you have this issue, either use the workout mentioned, or you can possibly solve this issue by using a relationship instead of a seperate fetch request from within the configurecell method. This really helped me out, thanks!
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Guidance
A row detail

Detail views are divided into sections. All the information in the data section comes from columns in the selected row. The other sections display data from other, related rows.

Related data can be related in a to-one or a to-many fashion. Captions of data related in a to-many fashion link to a list view showing a filtered view of the table.

Try moving around until you find a non-empty to-many entry and click on the label to get to one. You can move back to the root by clicking on the database name in the header.

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