[Cuis-dev] ATTENTION. maybe nasty bug in Time management on Summer/Winter time change

[Nicola Mingotti]

I put it here:
https://github.com/OpenSmalltalk/opensmalltalk-vm/issues/602

bye
Nicola




On 11/3/21 16:51, Nicola Mingotti wrote:
>
> Hi Gerald !
>
> thank you for looking into it !
>
> for me this is still too much above my head, I have
> not tweaked the VM up to now, and this seems a central subject
> that should be taken care by somebody who understands well
> the possible consequences of a change.
>
> I am going to forward the problem to the vm mailing list.
>
> bye
> Nicola
>
>
>
>
>
>
>
>
> On 11/3/21 12:05, Gerald Klix wrote:
>> Nicola,
>>
>> If you look at
>>
>> https://github.com/OpenSmalltalk/opensmalltalk-vm/blob/634e4e3c8556a72d54f43beefc3069c60e594a21/platforms/unix/vm/sqUnixHeartbeat.c#L139 
>>
>>
>> you see that "vmGMTOffset" is added to the new time.
>> "vmGMTOffset" is updated here:
>>
>> https://github.com/OpenSmalltalk/opensmalltalk-vm/blob/634e4e3c8556a72d54f43beefc3069c60e594a21/platforms/unix/vm/sqUnixHeartbeat.c#L150 
>>
>>
>> which is only called during VM initialization:
>>
>> https://github.com/OpenSmalltalk/opensmalltalk-vm/blob/634e4e3c8556a72d54f43beefc3069c60e594a21/platforms/unix/vm/sqUnixHeartbeat.c#L273 
>>
>>
>>
>> All this is only an educated guess.
>>
>>
>> HTH, Gerald
>>
>>
>> PS: This is really nasty, it may also ignore leap seconds:
>>
>> https://github.com/OpenSmalltalk/opensmalltalk-vm/blob/634e4e3c8556a72d54f43beefc3069c60e594a21/platforms/unix/vm/sqUnixHeartbeat.c#L135 
>>
>>
>>
>> On 11/3/21 10:56 AM, Nicola Mingotti via Cuis-dev wrote:
>>>
>>> Hi guys,
>>>
>>> I report you what i discovered this morning.
>>>
>>> . I have 2 services running in Cuis in 2 independent Linux/Debian 
>>> servers.
>>>
>>> . In weekend in Italy we changed time from CEST to CET
>>>
>>> . The OSes changed time correctly
>>>
>>> . But Cuis services are 1 hour forward !?!?
>>>
>>> . If i run a fresh new Cuis now in my laptop (Linux/debian vm), I 
>>> see it has the correct time, corresponding to the OS time
>>>
>>> . I did not change my localTimeZone in Cuis, in any machine. It is 
>>> acceptable for me it says UTC
>>>    even if it is actually localtime.
>>>
>>> . Seeing 'DateAndTime now' I discovered that Cuis by default uses 
>>> primLocalMicrosecondClock, so it should
>>>    always use the OS local clock and think it is in the UTC 
>>> timezone. But, it is not doing
>>>    so on images that were started some days ago (max 20). It does so 
>>> on new run images.
>>>
>>> I don't know well how to fix this. Maybe some time config is made 
>>> when Cuis starts up?
>>> It seems it is remembering the time when it was stared.
>>>
>>>
>>> EXTRA. NOT IMPORTANT AS THE PREVIOUS.
>>> If there are some changes to make I have a suggestion for improvement.
>>> Could we set localTimeZone to "system", or "local" ? At present we 
>>> are reading localTime from the OS
>>> and setting to UTC. Which is a bit confusing.
>>>
>>> bye
>>> Nicola
>>>
>>>
>>>
>>>
>
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