Open Radar

 
NSDateFormatter fails to provide a non-nil result parsing some strings with more that three fraction digits.

Steps to Reproduce:
1. Setup a NSDateFormatter with a dateFormat that has more than three (3) “S” symbols.
2. Parse a string with a fractional part like ".9994".
3. Parse a string with a fractional part like ".9995".

Expected Results:
Both 2 and 3 should result in a valid NSDate (even if we lose precision).

Actual Results:
Case 2 works without problem, while case 3 returns nil.

Regression:
I have been able to reproduce this in both 10.7 and 10.8 machines, and also in iOS 5.0 and iOS 6.0 devices.

Notes:
I attach a little test program that shows the problem. The program does the parsing of 10 test strings for a formatter that works as expected and other 10 test strings with a formatter that fails for the last 5 strings.

Attachments:

--- test-date-formatter.m ---
// clang -Wall -framework Foundation -o test-date-formatter test-date-formatter.m
#import <Foundation/Foundation.h>

int main(int argc, char *argv[]) {
  @autoreleasepool {
    NSString *problem0 = @"2013-01-15T17:34:26.9990Z";
    NSString *problem1 = @"2013-01-15T17:34:26.9991Z";
    NSString *problem2 = @"2013-01-15T17:34:26.9992Z";
    NSString *problem3 = @"2013-01-15T17:34:26.9993Z";
    NSString *problem4 = @"2013-01-15T17:34:26.9994Z";
    NSString *problem5 = @"2013-01-15T17:34:26.9995Z";
    NSString *problem6 = @"2013-01-15T17:34:26.9996Z";
    NSString *problem7 = @"2013-01-15T17:34:26.9997Z";
    NSString *problem8 = @"2013-01-15T17:34:26.9998Z";
    NSString *problem9 = @"2013-01-15T17:34:26.9999Z";

    NSString *noProblem0 = @"2013-01-15T17:34:26.990Z";
    NSString *noProblem1 = @"2013-01-15T17:34:26.991Z";
    NSString *noProblem2 = @"2013-01-15T17:34:26.992Z";
    NSString *noProblem3 = @"2013-01-15T17:34:26.993Z";
    NSString *noProblem4 = @"2013-01-15T17:34:26.994Z";
    NSString *noProblem5 = @"2013-01-15T17:34:26.995Z";
    NSString *noProblem6 = @"2013-01-15T17:34:26.996Z";
    NSString *noProblem7 = @"2013-01-15T17:34:26.997Z";
    NSString *noProblem8 = @"2013-01-15T17:34:26.998Z";
    NSString *noProblem9 = @"2013-01-15T17:34:26.999Z";

    NSDateFormatter *problemFormatter = [[NSDateFormatter alloc] init];
    problemFormatter.dateFormat = @"yyyy-MM-dd'T'HH:mm:ss.SSSS'Z";

    NSDateFormatter *noProblemFormatter = [[NSDateFormatter alloc] init];
    noProblemFormatter.dateFormat = @"yyyy-MM-dd'T'HH:mm:ss.SSS'Z";

    NSLog(@"%@ -> %@", problem0, [problemFormatter dateFromString:problem0]);
    NSLog(@"%@ -> %@", problem1, [problemFormatter dateFromString:problem1]);
    NSLog(@"%@ -> %@", problem2, [problemFormatter dateFromString:problem2]);
    NSLog(@"%@ -> %@", problem3, [problemFormatter dateFromString:problem3]);
    NSLog(@"%@ -> %@", problem4, [problemFormatter dateFromString:problem4]);
    NSLog(@"%@ -> %@", problem5, [problemFormatter dateFromString:problem5]);
    NSLog(@"%@ -> %@", problem6, [problemFormatter dateFromString:problem6]);
    NSLog(@"%@ -> %@", problem7, [problemFormatter dateFromString:problem7]);
    NSLog(@"%@ -> %@", problem8, [problemFormatter dateFromString:problem8]);
    NSLog(@"%@ -> %@", problem9, [problemFormatter dateFromString:problem9]);

    NSLog(@"%@ -> %@", noProblem0, [noProblemFormatter dateFromString:noProblem0]);
    NSLog(@"%@ -> %@", noProblem1, [noProblemFormatter dateFromString:noProblem1]);
    NSLog(@"%@ -> %@", noProblem2, [noProblemFormatter dateFromString:noProblem2]);
    NSLog(@"%@ -> %@", noProblem3, [noProblemFormatter dateFromString:noProblem3]);
    NSLog(@"%@ -> %@", noProblem4, [noProblemFormatter dateFromString:noProblem4]);
    NSLog(@"%@ -> %@", noProblem5, [noProblemFormatter dateFromString:noProblem5]);
    NSLog(@"%@ -> %@", noProblem6, [noProblemFormatter dateFromString:noProblem6]);
    NSLog(@"%@ -> %@", noProblem7, [noProblemFormatter dateFromString:noProblem7]);
    NSLog(@"%@ -> %@", noProblem8, [noProblemFormatter dateFromString:noProblem8]);
    NSLog(@"%@ -> %@", noProblem9, [noProblemFormatter dateFromString:noProblem9]);
  }
}
--- EOF ---