Open Radar

 
boundingRectWithSize in NSAttributedString and sizeThatFits in UILabel are inconsistent for some strings.

Steps to Reproduce:
- (void)stringSizeBug {
    NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle alloc] init];
    paragraphStyle.lineSpacing = 2;
    paragraphStyle.alignment = NSTextAlignmentCenter;
 
    NSDictionary *attributes = @{
        NSForegroundColorAttributeName : [UIColor whiteColor],
        NSParagraphStyleAttributeName : paragraphStyle,
        NSFontAttributeName : [UIFont systemFontOfSize:12]
    };
 
    NSDictionary *attributes2 = @{
        NSParagraphStyleAttributeName : paragraphStyle,
        NSFontAttributeName : [UIFont systemFontOfSize:12]
    };
 
    NSAttributedString *part1 = [[NSAttributedString alloc] initWithString:@"Add me here" attributes:attributes];
    NSAttributedString *part2 = [[NSAttributedString alloc] initWithString:@" − Get seen by millions!" attributes:attributes2];
    NSMutableAttributedString *text = [[NSMutableAttributedString alloc] initWithAttributedString:part1];
    [text appendAttributedString:part2];
 
    // Bug 1 in NSAttributedString
    NSLog(@"%@", NSStringFromCGSize([text boundingRectWithSize:CGSizeMake(251, 100) options:NSStringDrawingUsesFontLeading | NSStringDrawingUsesLineFragmentOrigin context:nil].size));  // {201.70800000000003, 16.315999999999999}
    NSLog(@"%@", NSStringFromCGSize([text boundingRectWithSize:CGSizeMake(226, 100) options:NSStringDrawingUsesFontLeading | NSStringDrawingUsesLineFragmentOrigin context:nil].size));  // {201.70800000000003, 14.315999999999999}
 
    // Bug 2 in UILabel
    UILabel *label = [[UILabel alloc] init];
    label.numberOfLines = 0;
    label.attributedText = text;
    NSLog(@"%@", NSStringFromCGSize([label sizeThatFits:CGSizeMake(251, 100)]));  // {202, 16.5}
    NSLog(@"%@", NSStringFromCGSize([label sizeThatFits:CGSizeMake(226, 100)]));  // {202, 14.5}
}

Or https://gist.github.com/diegosanchezr/8c740548fd51400ea34c

Expected Results:
I expect to get a consistent sizeThatFits/boundingRectWithSize if I provide enough size to fit.

Actual Results:
I get different sizes for two rects that can contain perfectly the string.

Version:
iOS 8

Notes:
It does not affect iOS 7.
It seems to be taking into account lineSpacing = 2, but only one line is required. It seems to be required that both parts in the attributed string have different arguments. In the example it's just the color.

Configuration:
iOS 8