Parsing two-digit year 16 with results in 0016 and not 2016

[DanTup]

import 'package:intl/intl.dart';
final dateFormat = new DateFormat("d/M/y H:m:s");
print(dateFormat.parse("01/02/16 12:11:12").year);

This code results in a year of 0016 and not 2016. Same thing happens whether I use y or yy in the format. Unfortunately it's tricky to fix this, because you can't even .add 2000 years, because the Duration class only goes up to days!

Other languages make assumptions about two-digit years being 19/20; it probably makes sense to do the same.

[andrewmcdnz]

Nearly 3 years later I've stumbled across the same issue via the unit tests in my Flutter app. The issue occurs even when using the specific example from the comments in date_format.dart (pattern: "MM/dd/yy", input "01/11/12" ; the resulting year is 0012). This contradicts in the description in date_format.dart (line 202) which states it should resolve to 2012. Needs to be fixed.

Tested with intl: ^0.15.8

[altherat]

A hacky workaround by adding Duration could be:

dateFormat.parse('01/02/16 12:11:12').add(Duration(milliseconds: DateTime(1970 + 2000).millisecondsSinceEpoch));

[jamesderlin]

@altherat That hacky workaround isn't correct since it will change the time. (That is, adding 24 * 60 * 60 seconds to a date might not necessarily be the same as incrementing the day by 1 due to leap seconds, daylight saving, ...).

An even bigger problem with your hack is that when this bug is fixed, your hack will be broken.

You'd be better off taking the result of DateFormat.parse and constructing a new DateTime with an adjusted year if it's between 0 and 99 inclusive.

[johnneijzen]

@jamesderlin that would problem but they did not fixed bug for 4 years already the closest to fixed is dart-archive/intl#125 but it got rejected

[harlandgomez]

I think @jamesderlin was right all along. I used the hacky workaround and after sometime it was giving me a wrong month. So I switched back to adding 2000 in the year as in var year = (dateFormat.parse("01/02/16 12:11:12").year + 2000)..

[jamesderlin]

I think @jamesderlin was right all along. I used the hacky workaround and after sometime it was giving me a wrong month. So I switched back to adding 2000 in the year as in var year = (dateFormat.parse("01/02/16 12:11:12").year + 2000)..

Please do not unconditionally add 2000. As I mentioned, such hacks will break when this bug is fixed. Add 2000 only to 2-digit years.

And yes, a fix is forthcoming.

[harlandgomez]

@jamesderlin, i was just showing how to simply add 2000, of course, there are checks before it arrives to that..

[jamesderlin]

@jamesderlin, i was just showing how to simply add 2000, of course, there are checks before it arrives to that..

Okay, I just don't want people to copy-and-paste that workaround blindly. I have seen other people also suggest workarounds that omit any checks.

[harlandgomez]

@jamesderlin, i was just showing how to simply add 2000, of course, there are checks before it arrives to that..

Okay, I just don't want people to copy-and-paste that workaround blindly. I have seen other people also suggest workarounds that omit any checks.

Understood, simple check can be?

    final twoDigitYear = dateFormat.parse("01/02/16 12:11:12").year;
    if(0 <= twoDigitYear && twoDigitYear <= 99){
      year = (twoDigitYear + 2000);
      //..
    }

[jamesderlin]

This is now fixed on master by b1335afc2e72cce096c78aa3b600e8b8424631ab.

[bsneider]

@jamesderlin when will 17.0 show up on pub.dev?

edit (this works in the interim)
dependency_overrides:
intl:
git:
url: git://github.com/dart-lang/intl
branch: master

[jamesderlin]

0.17 probably will not be available on pub.dev until package:intl is updated for NNBD. We're treating this fix as a breaking change. Changes for NNBD are also expected to be breaking, and we'd like to avoid publishing multiple breaking versions in a short timespan. I don't know what the timeline is.

In the meantime, yes, you can have your pubspec.yaml file point to the GitHub repository.

[jamesderlin]

A prerelease version of 0.17 is now available.