Different day formatting when using NSDateFormatter on OS X Mavericks and Yosemite

Given the following program:

#import <Foundation/Foundation.h>

int main(int argc, char *argv[]) {
    @autoreleasepool {
        NSDateFormatter *f = [[NSDateFormatter alloc] init];
        f.timeStyle = NSDateFormatterNoStyle;
        f.dateStyle = NSDateFormatterMediumStyle;
        f.calendar = [NSCalendar autoupdatingCurrentCalendar];
        f.timeZone = [NSTimeZone timeZoneWithAbbreviation:@"GMT"];
        f.locale   = [NSLocale localeWithLocaleIdentifier:@"ru"];

        NSDate *feb_01_2012 = [NSDate dateWithTimeIntervalSince1970:1328054400];

        NSLog(@"%@", [f stringFromDate:feb_01_2012]);
    }
}

      

        
        
        
      

    

When compiled on OS X, Yosemite produces the following output:

2014-12-08 22:31:49.109 Untitled[14149:1398844] 1 . 2012 .

      

        
        
        
      

    

However, when compiled on OS X Mavericks, it gives a slightly different output (note padding zeros on the day):

2014-12-08 22:27:01.890 formatter[54709:507] 01 . 2012 .

      

        
        
        
      

    

Any ideas why this might be happening? The error is only displayed for ru

locale: - \

UPDATE: Found a way to get the same number of zeros on both machines. Usage +dateFormatFromTemplate:options:locale:

gives the expected result:

NSLocale *l = [NSLocale localeWithLocaleIdentifier:@"ru"];
f.locale = l;
f.dateFormat = [NSDateFormatter dateFormatFromTemplate:@"yMMMd"
                                               options:0
                                                locale:l];