从 NSDateComponentsFormatter 获得糟糕的结果

Question

我最近了解到iOS8的新类NSDateComponentsFormatter。它允许您为时间跨度而不是日期生成时间字符串。很酷。我决定修改它，并编写了一些测试代码来创建各种时间跨度并记录输出。这是我的代码（英语和法语输出）

  NSCalendar *gregorian = [[NSCalendar alloc] initWithCalendarIdentifier:NSCalendarIdentifierGregorian];
  
  
  NSDateComponentsFormatter* formatter = [[NSDateComponentsFormatter alloc] init];
  formatter.unitsStyle = NSDateComponentsFormatterUnitsStyleFull;
  formatter.calendar = gregorian;
  
  formatter.allowedUnits = NSCalendarUnitYear + NSCalendarUnitMonth + NSCalendarUnitDay;
  
  NSDateComponents *components = [[NSDateComponents alloc] init];
  for (int years = 1; years <= 10; years++)
  {
    int days = arc4random_uniform(10);
    components.year = years;
    components.month = 3;
    components.day = days;
    NSString* outputString = [formatter stringFromDateComponents: components];
    NSLog(@"For %02d years %02d days, Date Components string = '%@'", years, days, outputString);
  }
  NSLocale *franceLocale = [NSLocale localeWithLocaleIdentifier: @"fr_FR"];
  gregorian.locale = franceLocale;
  formatter.calendar = gregorian;
  NSLog(@"--------------- French. --------------");
  for (int years = 1; years <= 10; years++)
  {
    int days = arc4random_uniform(10) ;
    components.year = years;
    components.day = days;
    NSString* outputString = [formatter stringFromDateComponents: components];
    NSLog(@"For %02d years %02d days, Date Components string = '%@'", years, days, outputString);
  }

（我不记录月份值，因为它是固定的。

下面是输出：

For 01 years 00 days, Date Components string = '1 year, 3 months'
For 02 years 05 days, Date Components string = '2 years, 3 months, 5 days'
For 03 years 01 days, Date Components string = '3 years, 3 months'
For 04 years 06 days, Date Components string = '4 years, 3 months, 6 days'
For 05 years 07 days, Date Components string = '5 years, 3 months, 7 days'
For 06 years 02 days, Date Components string = '6 years, 3 months, 1 day'
For 07 years 04 days, Date Components string = '7 years, 3 months, 4 days'
For 08 years 02 days, Date Components string = '8 years, 3 months, 2 days'
For 09 years 08 days, Date Components string = '9 years, 3 months, 8 days'
For 10 years 03 days, Date Components string = '10 years, 3 months, 2 days'
--------------- French. --------------
For 01 years 02 days, Date Components string = '1 année, 3 mois et 2 jours'
For 02 years 02 days, Date Components string = '2 années, 3 mois et 2 jours'
For 03 years 05 days, Date Components string = '3 années, 3 mois et 5 jours'
For 04 years 03 days, Date Components string = '4 années, 3 mois et 3 jours'
For 05 years 04 days, Date Components string = '5 années, 3 mois et 4 jours'
For 06 years 04 days, Date Components string = '6 années, 3 mois et 4 jours'
For 07 years 04 days, Date Components string = '7 années, 3 mois et 3 jours'
For 08 years 08 days, Date Components string = '8 années, 3 mois et 8 jours'
For 09 years 05 days, Date Components string = '9 années, 3 mois et 5 jours'
For 10 years 02 days, Date Components string = '10 années, 3 mois et 2 jours'

请注意，在某些情况下，格式化程序输出中的输出天数值与输入到其中的天数值不匹配。

有谁知道这里出了什么问题？对我来说，这看起来很像操作系统/框架错误。

编辑：

我在 OS X 版本 10.10.5 下的 Mac 应用程序中运行了我的测试代码 其他人是否正在运行 10.10.5，他们可以尝试吗？

对于 8.1 模拟游戏，我也得到了一个错误的答案。（对于输入值 07 年、3 个月、06 天，日期组件字符串 = '7 年、3 个月、5 天'）

Answer 1

看起来iOS

8.x和Mac OS 10.10版本的NSDateComponentsFormatter有问题。在这些操作系统版本中，我得到（间歇性！）不同、错误的结果，但来自最新操作系统版本的正确结果。

叹息。。。