Function for asserting that a code path isn’t called from a subclass of a given class.

ASTAssertStack.m

void ASTAssertNotCalledFromSubclassOfClass(Class doNotCallFromThisClass) {
    NSString *bundleName = [[[NSBundle mainBundle] infoDictionary] objectForKey:(__bridge NSString *)kCFBundleNameKey];
    for (NSString *symbol in [NSThread callStackSymbols]) {
        if ([symbol containsString:bundleName]) {
            NSRange openBracketRange = [symbol rangeOfString:@"["];
            if (openBracketRange.location != NSNotFound) {
                NSRange searchRange = NSMakeRange(openBracketRange.location, (symbol.length - openBracketRange.location));
                NSRange nextSpaceRange = [symbol rangeOfString:@" " options:0 range:searchRange];
                if (nextSpaceRange.location == NSNotFound) {
                    // well, this shouldn't happen…
                    continue;
                }
                NSUInteger classNameLocation = (openBracketRange.location + 1);
                NSUInteger classNameLength = nextSpaceRange.location - classNameLocation;
                NSRange classNameRange = NSMakeRange(classNameLocation, classNameLength);
                NSString *className = [symbol substringWithRange:classNameRange];
                Class aClass = NSClassFromString(className);
                if (aClass) {
                    if ([aClass isSubclassOfClass:doNotCallFromThisClass]) {
                        NSAssert(NO, @"No, seriously, do not call this method from %@", NSStringFromClass(doNotCallFromThisClass));
                        continue;
                    }
                }
            }
        }
    }
}

example.m

@implementation AppDelegate

- (UIViewController *)viewControllerForAwfulHacks {
    // YOU ALREADY HAVE A VIEW CONTROLLER, JUST USE THAT
    ASTAssertNotCalledFromSubclassOfClass([UIViewController class]);
    return self.window.rootViewController;
}