New NSString substringWithRange: Error Message

Question

I'm getting an interesting new error with iOS 4:

-[NSCFString substringWithRange:]: Invalid range {11, 4294967295}; this will become an exception for apps linked on SnowLeopard. Warning shown once per app execution.

The error is caused by a snippet of code I got from a blog post that helps Title Case a string, and it's not going to be hard to fix, but I haven't seen this mentioned anywhere else, and I'm assuming Apple wants people to stop using the magic 4294967295 number.

Does anyone know about the history / background of this change?

EDIT: Source for the Title Case code is located at: http://vengefulcow.com/titlecase/ It's the objective-c port (obviously). Line 116 is the offender. Clearly it's a problem only under some specific condition. I'm still tracking it down.

Answer 1

Unsigned 4294967295 is the same as the signed uint32_t value for -1. I've seen problems where a 32 bit app archived -1 and a 64 bit app unarchived it as a Big Ass Length (terribly fun when it was Xcode calling malloc(4294967295) during the 64-bit bring-up).

The Cocoa frameworks are detecting that you passed in a range where the length is longer than the string itself. Warning now, with truncated results, but it'll be a hard error in the future.

(In some cases, NSNotFound can cause these kinds of issues).