Bug 12574 - Inconsistency in to summertime hour change
Summary: Inconsistency in to summertime hour change
Status: NEW
Alias: None
Product: Class Libraries
Classification: Mono
Component: System ()
Version: 2.10.x
Hardware: PC Linux
: --- normal
Target Milestone: Untriaged
Assignee: Bugzilla
Depends on:
Reported: 2013-06-06 06:24 UTC by Kano
Modified: 2013-06-06 06:24 UTC (History)
1 user (show)

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

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Description Kano 2013-06-06 06:24:52 UTC
When system changes the time into the summertime hour there is a period of 1 hour where mono informs an incorrect local time.

Having debian system in Europe/Madrid timezone, this year the time change has been at 31/3/2013 at 2:00 changes time to 3:00. This means passing from gmt+1 to gmt+2.

Using this command:
Console.WriteLine(string.Format("UTC [{0:dd/MM/yy-HH:mm:ss}] - Local [{1:dd/MM/yy-HH:mm:ss}] (+{2:0})", DateTime.UtcNow, DateTime.Now, DateTime.Now.Subtract(DateTime.UtcNow).TotalHours));
Before the time change I obtain:
UTC [31/03/13-00:59:33] - Local [31/03/13-01:59:33] (+1)
UTC [31/03/13-00:59:34] - Local [31/03/13-01:59:34] (+1)

Just after time changes and for an hour I obtain:
UTC [31/03/13-01:00:35] - Local [31/03/13-01:00:35] (+0)
UTC [31/03/13-01:00:36] - Local [31/03/13-01:00:36] (+0)

One hour after the time changes I obtain:
UTC [31/03/13-02:01:00] - Local [31/03/13-04:01:00] (+2)
UTC [31/03/13-02:01:01] - Local [31/03/13-04:01:01] (+2)

In the winter time change al works correctly.
The tests had been done with a Mono 2.8 version and with a 2.10.8

Thanks in advance