Question

I have a requirement to remove a previous view controller in a stack. I have successfully used this method in the past, without any problems:

NSMutableArray *vcs = [NSMutableArray arrayWithArray:self.navigationController.viewControllers];
    BOOL removedFlag = YES;
    while (removedFlag == YES)
    {
        removedFlag = NO;
        for (UIViewController *vc in vcs)
        {
            if( ![vc isKindOfClass:[self class]] && ![vc isKindOfClass:[MenuVC class]] )
            {
                [vcs removeObject:vc];
                removedFlag = YES;
                break;
            }
        }
    }
    [self.navigationController setViewControllers:[NSArray arrayWithArray:vcs]];

Now I’m updating the app, and it mysteriously crashes on release configuration, not on debug. In addition, there are no warnings whatsoever in debug mode. I think something changed with the SDK. It never did this before.

I’ve made a sample project available:
http://dl.dropbox.com/u/7834263/RemoveTest.zip

This is an ARC-enabled project.

Answer 1

The first line should actually be:

NSMutableArray *vcs = [self.navigationController.viewControllers mutableCopy];

NSMutableArray is a subclass of NSArray. arrayWithArray is a method of the NSArray class — it creates an immutable array. The mutableCopy method creates a mutable copy of the original array. You never really should have been able to call removeObject on your vcs array because it was never actually an NSMutableArray — it was an NSArray.