Cannot convert to NSDate from this specific date (1994-04-01) String - ios

Question

Something strange happen to me.
I'm not able to convert this specific date (1994-04-01) String.
Can anyone check this and let me know if it reproduce in your code?
Steps to Reproduce:
Swift:-
let dateString = "1994-04-01"
let dateFormatter = DateFormatter()
dateFormatter.dateFormat = "yyyy-MM-dd"
let dateFromString = dateFormatter.date(from: dateString)
Obj c:-
NSDateFormatter *formatter = [[NSDateFormatter alloc]init];
[formatter setDateFormat:#"yyyy-MM-dd"];
NSString *birthdayStr = #"1994-04-01";
NSDate *birthday = [formatter dateFromString:birthdayStr];
Expected Results:
birthday = 1994-03-31 21:00:00 +0000
In UTC
Actual Results:
birthday = nil
Version:
Xcode ver :- Version 8.1 (8B62)
OS X ver :- 10.12.1 (16B2555)
you can try any different date then (1994-04-01) and it will work fine.

Answer 1

Test code:
import Foundation
for timeZoneId in TimeZone.knownTimeZoneIdentifiers {
let dateString = "1994-04-01"
let dateFormatter = DateFormatter()
dateFormatter.timeZone = TimeZone(identifier: timeZoneId)
dateFormatter.dateFormat = "yyyy-MM-dd"
if dateFormatter.date(from: dateString) == nil {
print(timeZoneId)
}
}
Output:
Asia/Amman
Asia/Damascus
Asia/Gaza
Asia/Hebron
Asia/Jerusalem
I conclude your system time zone is set to one of the ones printed. If I type “jerusalem time zone 1994” into Google, the first result tells me that Daylight Saving Time started at midnight on April 1 in 1994. This means there was no midnight. The first instant of April 1, 1994 was in fact 1 AM in that time zone.
A DateFormatter uses a time of day of midnight by default when not parsing a time of day from the string. This makes it fail when midnight doesn't exist on the date in the string.
The solution is to not use midnight as your default time of day. Noon is a much safer default time. So, one solution is to include the time of day in the input and parse it in the format:
let dateString = "1994-04-01 12:00:00"
let dateFormatter = DateFormatter()
dateFormatter.timeZone = TimeZone(identifier: timeZoneId)
dateFormatter.dateFormat = "yyyy-MM-dd HH:mm:ss"
Another solution is to give the date formatter a default date that is noon of some day:
// Reference date was 00:00:00 UTC on 1 January 2001. This is noon of the same day in UTC.
dateFormatter.defaultDate = Date(timeIntervalSinceReferenceDate: 12*60*60)
If you are going to do any date parsing or manipulation on iOS or macOS, it would be a very good idea to watch WWDC 2013 Session 227: Solutions to Common Date and Time Challenges.