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

[Juan Vuletich]

On 11/11/2021 2:20 PM, Gerald Klix via Cuis-dev wrote:
> Looks OK for me!
>

Thanks for the feedback! It is great to have at least another couple of 
eyes on this. Just pushed it to GitHub.

>
> HTH,
>
> Gerald
>
>
> PS: When filed into Haver it revealed anothe rbug in
> Haver's environment management code.

That's a good thing, I hope!

Cheers,

> On 11/9/21 10:19 PM, Juan Vuletich via Cuis-dev wrote:
>> After comments from Gerald (below) and Dave (at the opensmalltalk-vm 
>> issue you opened), this is my take.
>>
>> This touches a rather basic area of the system, so any bug could 
>> affect a lot of code. Folks, please, review.
>>
>> Thanks,
>>
>> On 11/3/2021 1:08 PM, Nicola Mingotti via Cuis-dev wrote:
>>>
>>> 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
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>
>>>
>>
>>
>>


-- 
Juan Vuletich
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