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Synching past DST borders incorrect

Posted: Wed Nov 18, 2009 8:06 pm
by TCroezing
Can somebody help me?
I have Thunderbird with Lightning 0.9 on the pc and Windows Mobile 6.0 on my PPC (and birdiesync ofcourse).

I encoutered a problem with the same event being different om my pc and ppc. I dived into it and found where it was all about. Here an easy way to reproduce the bug...

When you create an event on the pc, at 20:00 on sun 25 okt 2009, it will be correctly synchronized to the ppc (displayed as 20:00 on sun 25 okt). However, if you only change the day of this event (on the pc) to sat 24 oct, it will display on the ppc as 19:00! And you know what, this is the night the daylight savings time correction jumps in...
The timezone on pc and ppc are correctly set (GMT+1).

Maybe you think, hey, why is an event in the past important? Well, to me it seems it cannot be trusted, and that's a dealbreaker for me. And btw., its even worse. Try now to make an event at 2 april 2010 on 20:00, it will sync to an 19:00 event on the ppc!!

It seems events cannot be made in an other than you current dst status.

Or am I missing something here? Please advice!

Re: Synching past DST borders incorrect

Posted: Thu Nov 19, 2009 9:38 am
by Birdy
Hello TCroezing,

I made some tests synchronizing an event before and after DST change and the start/end times were properly synchronized on the mobile device.
"The timezone on pc and ppc are correctly set (GMT+1)."
Actually there are 3 time zones involved in the process: the mobile device one, the Lightning one and the Windows one. Note that the Windows one could change the way the time is displayed in Lightning even if the values are correct internally.
To get correct results, all these time zones should be identical. GMT+1 is not enough since it doesn't say which DST rule is applied (on which day the DST change happpens). So you should mention the exact name of all your time zones (for instance Europe/Paris in Lightning).

The problem you may have is that although the time zones seem identical, their DST definitions are not. These definitions can change every year. Sometimes these definitions can be incorrect on the mobile device or even in Lightning because they are no longer up to date: the DST change will happen 1 week too early for instance on the mobile device compared to the desktop.

To see if it is the case, I would try to synchronize an event several weeks before the supposed DST change (and not the same day) and check if the times are correct. Of course, you must ensure that the time zones that you chose are supposed to have the same DST rule (same country/town and not just GMT+1 for instance).

It would also be a good idea to apply some patches if necessary to ensure you're up to date regarding your time zone definitions as described in this FAQ topic.

Does it help or do you still have the same problem ?

Re: Synching past DST borders incorrect

Posted: Thu Nov 19, 2009 2:47 pm
by TCroezing
Ok, thank you very much Birdy for you answer! :D Here are my findings.

On my Windows Mobile the clocksetting is: GMT+1 Amsterdam
In my Windows 7 the timezone is: UTC+1, Amsterdam, Berlijn, ...
In Lighning the timezone is: Europa/Amsterdam

Those are all alike aren't they?

The website said:
DST started on zondag, 29 maart 2009, 02:00 local standard time
DST ended on zondag, 25 oktober 2009, 03:00 local daylight time

Since you suggested a possible problem concerning the difference in date of DST change, I did some other tests making sure not to step on this bug.

pc: make event on 27 aug 2009 at 15:00
after sync:
mobile: event on 27 aug 2009 starts at 14:00

pc: make event on 27 aug 2010 at 15:00
after sync:
mobile: event on 27 aug 2010 starts at 14:00

These examples were way from the DST change boundaries, so no bugs buggering us here...

And counterwise:

mobile: make event on 27 aug 2009 at 15:00
pc: event on 27 aug 2009 starts at 16:00

mobile: make event on 27 aug 2010 at 15:00
pc: event on 27 aug 2010 starts at 16:00

(At least it is logical ;-)

I made an event on the mobile on 27 aug at 15:00, and the same one on 27 nov. Comparing the 2 exported ics-files, I found (except the obvious):


Btw, dunno if its interesting. I found in the ThunderbirdServiceLog of BirdieSunc the following:
Local 2009-11-19 10:17:22::0131 BirdieSync: version
Local 2009-11-19 10:17:22::0162 Operating system: id 2, version 6.1, SP 0.0
Local 2009-11-19 10:17:22::0193 Test version: Sep 3 2009 14:26:01
Local 2009-11-19 10:17:22::0240 Thunderbird: version
Local 2009-11-19 10:17:22::0271 Lightning extension: version 0.9
Local 2009-11-19 10:17:22::0380 Lightning extension is enabled
Local 2009-11-19 14:10:06::0011 WARNING: Get succeeded but returned item is NULL, id = '487c0525-8adb-46a5-9614-791c8b27ae69' (GetLastError = 0)
Local 2009-11-19 14:11:33::0981 ERROR: Could not find profile file for classical application: C:\Users\Benno\AppData\Roaming\Mozilla\Sunbird\\\profiles.ini (GetLastError = 0)

It searches for sunbird, allthough I use TB with lightning. I do have my profile in a different then default directory (but that shouldn't be a problem).

The thunderbirdProfilePath in the Preferences.xml is OK.

And, this ThunderbirdService.log doesn't have the error as stated in the faq: "Time zone are different on device (offset = ...) and desktop (offset = ...)".

Strange problem isn't it? :?

Btw., is there a way to see _what excactly_ has been synchronized? You can e.g. see a brief line that x events are synced, but not which event and how. Is there a loglevel to get more detail?

Last question, is it normal that syncing is not triggered, entering an event in TB-lightning? When I enter an event in my mobile, after the OK btn, an immediate sync is triggered.

If you need any more info, please ask!

Hope this all helps?...

Thx in advance!

Re: Synching past DST borders incorrect

Posted: Thu Nov 19, 2009 3:59 pm
by Birdy
That's really weird. I made some tests again with Paris time zone (which have the same settings as Amsterdam) and had no problem at all. I tried on WM6.5 and 2003.
I didn't find any "GMT+1 Amsterdam" timezone on the mobile device. Could you confirm that you have it (it may be specific to the Netherlands version) ? Which other GMT+1 time zones do you have on your mobile device ?
Do you use Pocket Outlook or another software ?

Presently there is no way to see the details of the synchronization.
The automatic synchronization of the items modified on the desktop haven't been provided yet. But it could be offered in the future.

Re: Synching past DST borders incorrect

Posted: Thu Nov 19, 2009 5:59 pm
by TCroezing
Talking about wierd...

I have good and bad new. The good news is, it's solved. The bad news, its not statisfactory...
What have I done. :roll:

I thought to check again the timesetting on ppc, and found it was GMT+1 Prague! Strange, since I'm sure to have changed it. Appears there's a bug. Changing Prague to Amsterdam doesn't trigger a change, so no save. :o Going to GMT+1 Warchau does, so it did it via that way, now being sure it was GMT+1Amsterdam. (Btw. Prague is excactly the same as Amsterdam for dst changes, I checked :) ).
Now being sure having GMT+1A'dam I softresetted the ppc (I think the first after using BirdieSync). Now it works. 15:00 at 27 aug is 15:00 in pc AND ppc!
I even tried again Prague, but no problems.

Anyhow, it seems it works 4 now. :D

Birdy THX alot for your support!