Re: UTC or not UTC for timestamps in the past ([FEATURE REQUEST] Timezone support in org-mode)

[Max Nikulin <manikulin@gmail.com>]

On 24/01/2023 09:44, Thomas S. Dye wrote:
> Max Nikulin writes:
>>
>> I believed that [2023-01-22 Sun 08:29@+1100] unambiguously suggests 
>> offset from UTC.
> 
> Not for a casual programmer like me. The timestamp alone might easily be 
> read as 11 hours ahead of local time. Nevertheless, Org is certainly 
> free to interpret it as relative to UTC.

My primary concern is that I might be wrong assuming that format like 
[2023-01-22 Sun 08:29@+1100] with offset in respect to UTC is reciprocal 
identity  mapping to UTC.

Of course there are a lot of people unaware of UTC. Org users may be 
educated by the manual and by hints in UI pushing toward time fixed in 
respect to UTC when "global" timestamp should be added. (In the sense of 
e.g. Lunar eclipse or an on-line meeting, not to confuse with set of 
events appointed on specific date but starting at the same local time in 
each location).

I am afraid of confusion with repeater intervals, but syntax has not 
fixed yet.

So we had different types of ambiguity in mind. Base time for offset was 
unclear for you, I was writing about mapping to UTC. Your point should 
be taken into account during consideration of storage format.

I still believe that something like [2023-01-21 Sat 21:29:00Z] and 
[2023-01-22 Sun 08:29@+1100] may be used to store timestamps 
interchangeably.

>> Are there local references that may confuse users? I mean something 
>> like 9 hours
>> ahead of Moscow (Asia/Kamchatka) used in USSR.
> 
> I think 9 hours ahead of a timezone with a potentially variable offset 
> from UTC has the potential to sow confusion, yes.

If someone has examples of local time offsets (unrelated to UTC) widely 
used in some area, please, post them.

MSK+3 style was not a real issue because daylight saving time was active 
during the same period in the whole country and iron curtain was 
efficiently isolating most of people form variety of DST rules in other 
areas.