editingStyleForRowAtIndexPath — fires in iOS 5, does not fire in iOS 6

Question

I have simple master and detail view controllers connected with two segues, one for "show detail" and one for "add new".

• "Show detail" segues to the detail view controller with setEditing:NO.
• Tap "+" (add icon) segues to the detail view controller with setEditing:YES

iOS 5.1: "+" works as I expect, the detail page is in edit mode and editingStyleForRowAtIndexPath fires to show the insert and delete indicators.

iOS 6.0: the "+" makes the transition to the detail page but editingStyleForRowAtIndexPath never fires. Other code that is in setEditing:YES gets executed. didSelectRowAtIndexPath does fire (delegate = self).

Once on the detail page edit mode works as expected in both cases.

Any ideas?

// Master.m
if([[segue identifier] isEqualToString:@"NewRecipe"]) {

    DetailViewController *detailViewController = [segue destinationViewController];
    // stuff
    detailViewController.recipe = r;     
    detailViewController.delegate = self;
    detailViewController.editing = YES;
}


// Detail.m
-(void)setEditing:(BOOL)flag animated:(BOOL)animated {

   if (flag) {

   [self.tableView setEditing:flag animated:YES];
   [self.tableView beginUpdates];
   // the row does get added
   [self.tableView insertRowsAtIndexPaths:@[pathToAdd] withRowAnimation:UITableViewRowAnimationAutomatic];  
    // datasource gets updated here
    [self.tableView endUpdates];
    .... 
    }
}

Answer 1

I figured it out. I don't know why this is the fix, I hope this does not replace bad code with worse code.

 Master.m
// iOS 5 -- this is OK
detailViewController.editing = YES;

For iOS 6 I needed the detailViewController to make a call to a delegate method to determine whether to setEditing:YES.

Master.m
-(BOOL)isNewRecipe {
    return (_isNewRecipe == 1);
}

Detail.m
if ([self.delegate isNewRecipe]) {
    [self setEditing:YES];        
}