Strange crash in UITextview undo on iOS 7
问题 I have been receiving a bunch of crash reports that look a lot like the following with different values for the range. Sometimes the range is not 0-x it could be say 2-x Application Specific Information: * Terminating app due to uncaught exception \'NSRangeException\',reason: \'* -[NSBigMutableString substringWithRange:]: Range {0, 69} out of bounds; string length 0\' Last Exception Backtrace: 0 CoreFoundation 0x2e879e83 __exceptionPreprocess + 131 1 libobjc.A.dylib 0x38bd66c7 objc_exception