This nil-swallowing behaviour works really well with the "out error parameter" pattern of Cocoa methods. In short, methods that can fail have a signature like:

- (id)thingThatSometimesWorks:(NSError *)error;

You can chain these to your heart's content. The one that fails sets the error and returns nil; following messages are sent to nil which does nothing and a particular characteristic of doing nothing is that it doesn't overwrite the error that was set. So you still get to see the error when the workflow finishes.

As an objective-C programmer, I also have a tool in my toolbox which gives NSNull the same message-swallowing behaviour as nil.

@implementation NSNull(GJLNilReceiver)

- (NSMethodSignature *)methodSignatureForSelector:(SEL)aSelector { return [super methodSignatureForSelector:aSelector] ?: [NSMethodSignature signatureWithObjCTypes:"@@:"]; }

- (void)forwardInvocation:(NSInvocation *)anInvocation { [anInvocation invokeWithTarget:nil]; }

@end