bug#55635: `make-decoded-time' incorrectly sets DST to nil, it should be -1 (guess)

[Maxim Nikulin <m.a.nikulin@gmail.com>]

On 28/05/2022 17:41, Lars Ingebrigtsen wrote:
> Paul Eggert writes:
> 
>> To try to lessen the confusion I installed the attached, which fixes
>> the reported bug so I'll close the bug report. Please feel free to
>> revert if you see a problem with it (I'm just trying to save time here
>> by being bold).
> 
> Thanks; I think that looks like the correct thing here.

Thank you, with the committed changes my examples work as I expect.

Paul, do you have any comment concerning the last part of the bug report?

`decoded-time-add' docstring:
 >   (decoded-time-add (decode-time) (make-decoded-time :month 2))

I think, it is confusing that `make-decoded-time' is used to create 
timestamps *and* time intervals. They are different types, for example 
sum of intervals is meaningful (despite may be ambiguous) while there is 
no point to add timestamps. Daylight saving time and timezone are 
something alien for intervals. Though I am unsure if it is reasonable to 
mark intervals by e.g. 'time-interval symbol or to make these types 
distinct by some other way.