Bug 28636 - ToLocalTime() not working when enabling linker
Summary: ToLocalTime() not working when enabling linker
Alias: None
Product: iOS
Classification: Xamarin
Component: XI runtime ()
Version: XI 8.8.0
Hardware: PC Windows
: Normal normal
Target Milestone: Untriaged
Assignee: Bugzilla
Depends on:
Reported: 2015-04-01 11:26 UTC by jm.alfonsi
Modified: 2015-04-15 13:21 UTC (History)
3 users (show)

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

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Description jm.alfonsi 2015-04-01 11:26:33 UTC
I have a Xamarin.iOS unified app. I pull objects with DateTime from a REST service.
These DateTime are UTC. For display, I convert them to local time using ToLocalTime() (I am in CET time zone), so far so good.

Now when I don't link the project (iOS Build -> Linker Options -> Don't link), everything is working fine.
When I link the project (iOS Build -> Linker Options -> Link SDK assemblies only), ToLocalTime() is wrong.

iOS SDK version used is 8.2.
Comment 1 Sebastien Pouliot 2015-04-01 15:47:52 UTC
The linker does not change anything about the dates/time zones. This code runs identically with or without the linker enabled (EST time zone).

		public void D ()
			var x = DateTime.UtcNow;
			Console.WriteLine (x);
			var y = x.ToLocalTime ();
			Console.WriteLine (y);

Linker enabled:

2015-04-01 15:44:08.509 linkall[17199:19531250] 4/1/2015 7:44:08 PM
2015-04-01 15:44:09.980 linkall[17199:19531250] 4/1/2015 3:44:08 PM

Linker disabled:

2015-04-01 15:45:12.190 linkall[17228:19537035] 4/1/2015 7:45:11 PM
2015-04-01 15:45:13.331 linkall[17228:19537035] 4/1/2015 3:45:11 PM

However REST services are generally used with serialization and that might need some extra care (reflection being used) to ensure unused code is not removed. I strongly suspect the issue exists before the conversion to local time. 

Is it possible to provide a test case ?

You can also try to print the date (e.g. `dt.Ticks`) before and after the conversion (ToLocalTime). My guess is that the conversion is correct but the original value (deserialized from the REST response) is different.
Comment 2 jm.alfonsi 2015-04-15 13:21:13 UTC
Yes, it's definitely an issue from the way we deserialize the DateTime from the REST service.
I close this one, it's not relevant.