Bug 7953 - TimeZoneInfo returns NULL for NZDT
Summary: TimeZoneInfo returns NULL for NZDT
Alias: None
Product: Android
Classification: Xamarin
Component: BCL Class Libraries ()
Version: 4.2.x
Hardware: Macintosh Mac OS
: High normal
Target Milestone: ---
Assignee: Radek Doulik
Depends on:
Reported: 2012-10-23 17:07 UTC by Nic Wise
Modified: 2014-04-28 14:02 UTC (History)
9 users (show)

Is this bug a regression?: ---
Last known good build:

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Description Nic Wise 2012-10-23 17:07:34 UTC
This piece of code, from ServiceStack.Text (well, I've distilled it from there)

var tz = TimeZoneInfo.Local;
var offset = tz.GetUtcOffset(DateTime.Now);

Causes a NullReferenceException (tz / TimeZoneInfo.Local is null) when the timezone of the device is NZDT (GMT+13). Which it is now, in New Zealand.

I have tested this on Android 2.3 and another version (4.x - not sure, it was a customers device) and I can reproduce it.

I also tried it on iOS6 / MonoTouch 6.0.3 (latest beta), and it works fine.

For context, it's here in SS.T:

Comment 1 Jonathan Pryor 2012-10-24 16:47:26 UTC
And for more context, here's how we determine the default timezone:


What is the output of:

    adb shell getprop persist.sys.timezone

If the persist.sys.timezone system property is empty, this is probably a dup of Bue #4902. If it isn't empty, this may be a dup of Bug #7966 (and a TimeZoneNotFoundException should be thrown instead of `null` being returned).
Comment 2 Nic Wise 2012-10-24 17:10:15 UTC
Thanks Jon

cynophobia:platform-tools nic$ ./adb shell getprop persist.sys.timezone
cynophobia:platform-tools nic$ 

Thing is, Pacific/Auckland is VERY VERY valid. (I was born there)
Comment 3 Jonathan Pryor 2013-03-05 12:11:13 UTC
Setting status to NEW as Nic provided the requested info.
Comment 4 Peter Hultqvist 2013-04-23 10:25:21 UTC
I have currently the same issue where Json.NET crash because TimeZoneInfo.Local is null.

This was on a brand new device(LG) without a sim card and time zone settings set to automatic(from network).

Using adb the persist.sys.timezone was reported as an empty line.

On the phone the timezone is reported as GMT+00:00.
Perhaps this could be used when persist.sys.timezone is empty.

After setting the timezone manually in the settings the error no longer occurs.
Comment 5 Jonathan Pryor 2013-06-25 16:16:42 UTC
Fixed in master/bd1efe1d, and should make it into the 4.8 release.

The problem? I was searching for strings wrong: https://github.com/mono/mono/commit/ac11abe1
Comment 7 jimm@tbsmobility.com 2013-09-10 09:45:25 UTC
Hey Guys,  

Sorry to re-open this, but we upgraded a Nexus 7 to 4.3 and now at runtime, the value of TimeZoneInfo.Local is null again. This showed-up as an exception from Newtonsoft.Json.

> adb shell getprop persist.sys.timezone

Thought I'd add to this instead of opening a new bug with the same description.
Comment 8 Jonathan Pryor 2013-09-10 11:14:09 UTC
TimeZoneInfo.Local null on Android v4.3 is Bug #13686, which if fixed in Xamarin.Android 4.8.2.
Comment 9 Trent 2013-12-17 18:52:14 UTC
We ran into the same thing today using 4.10.2 and Android 4.1.2 on a Samsung Galaxy Note 2 that no longer has a sim card installed.  Runs fine on Nexus 5 and Android 4.4.2.
Comment 10 Jonathan Pryor 2013-12-20 16:32:57 UTC
@Trent: What's the output of the following command?

    adb shell getprop persist.sys.timezone
Comment 11 Trent 2014-01-06 16:33:56 UTC
@Jon: It is blank on my Galaxy Note 2 running 4.1.2.   Nexus 5 running 4.4 is America/Denver
Comment 12 Gerry 2014-03-01 09:13:38 UTC
It is also null in the GenyMotion simulator for a Nexus 5.  Running Xamarin.Android 4.12.1
Comment 13 Miha Markic 2014-04-26 10:34:06 UTC
I see it, too, with Genymotion (random OS). I think you should set timezone there manually (avoid get timezone from network). It looks to like an Android problem. Or perhaps there is another way to retrieve TimeZone or set a default one if none is set.
Comment 14 Gerry 2014-04-28 12:42:51 UTC
It would be nice if there were a solution or workaround for this.  It is still there in Xamarin.Android 4.12.3
Comment 15 Jonathan Pryor 2014-04-28 14:02:32 UTC
There are two different bugs on this thread:

1. TimeZoneInfo.Local is null when the persist.sys.timezone system property is NOT null; and
2. TimeZoneInfo.Local is null when persist.sys.timezone IS null.

Bug (1) is Comment #0 through Comment #3, and was fixed in Xamarin.Android 4.8. (Then a ~repeat for Android v4.3+, via Comment #7 and Bug #13686.)

Bug (2) is Comment #4 and Comment #9 through 14; these are duplicates of Bug #4902, which will be fixed in the forthcoming Xamarin.Android 4.14 release.