How to handle NSFetchedResultsController fetch errors?

Well, apparently nobody has another (better?) solution, so here is my approach:

In my AppController I added a instance variable errorString and this method:

- (void)presentCoreDataError:(NSError *)error                    withText:(NSString *)text{    NSMutableString *localErrorString = [[NSMutableString alloc] init];    [localErrorString appendFormat:@"Failed to %@: %@", text, [error localizedDescription]];    NSArray* detailedErrors = [[error userInfo] objectForKey:NSDetailedErrorsKey];    if(detailedErrors != nil && [detailedErrors count] > 0) {        for(NSError* detailedError in detailedErrors) {            [localErrorString appendFormat:@"- Detail: %@", [detailedError userInfo]];        }    } else {        [localErrorString appendFormat:@"- %@", [error userInfo]];    }    UIAlertView *alert = [[[UIAlertView alloc] initWithTitle:[NSString stringWithFormat:@"Failed to %@", text]                                                     message:@"Please send a report to the developer."                                                    delegate:self                                           cancelButtonTitle:@"Cancel"                                           otherButtonTitles:@"Send Report", nil] autorelease];    [alert show];    self.errorString = localErrorString;    [localErrorString release];}

The UIAlertView delegate displays an MFMailComposeViewController with the errorString in the cool courier font :) if "Send Report" is tapped. Otherwise it calls abort():

- (void) alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex{    if (buttonIndex == 1) {     // Send Report        MFMailComposeViewController *picker = [[MFMailComposeViewController alloc] init];        picker.mailComposeDelegate = self;        NSArray *toRecipients = [NSArray arrayWithObject:@"first@example.com"];        [picker setToRecipients:toRecipients];        [picker setSubject:@"Error Report"];        [picker setMessageBody:[NSString stringWithFormat:@"The application crashed with the following error:<br><br><FONT FACE=%@> %@ </FONT>",                                 @"courier", errorString]                         isHTML:YES];        [navigationController presentModalViewController:picker animated:YES];        [picker release];    } else {        abort();    }}

And the MFMailComposeViewControllerDelegate displays a second UIAlertView with only one button (obviously the button has index 0, so it will call abort()):

- (void)mailComposeController:(MFMailComposeViewController *)controller          didFinishWithResult:(MFMailComposeResult)result                        error:(NSError *)error{    [navigationController dismissModalViewControllerAnimated:YES];    NSMutableString *messageString = [[NSMutableString alloc] init];    if (result == MFMailComposeResultSent) {        [messageString appendFormat:@"Thanks! "];    }    [messageString appendFormat:@"The application has to quit now."];    UIAlertView *abortAlert = [[[UIAlertView alloc] initWithTitle:nil                                                          message:messageString                                                         delegate:self                                                cancelButtonTitle:@"OK"                                                otherButtonTitles:nil] autorelease];    [abortAlert show];    [messageString release];}