bug#78096: 31.0.50; calendar-iso-to-absolute and %W time string format are inconsistent

[Ihor Radchenko]

Stephen Berman <stephen.berman@gmx.net> writes:

> The doc string of `format-time-string' says:
>
> %U is the week number starting on Sunday, %W starting on Monday,
>  %V the week number according to ISO 8601.
>
> (format-time-string
>   "%Y-%m-%d W%V"
>   (encode-time (parse-time-string "2025-01-06 00:00")))
> => "2025-01-06 W02"

That indeed explains it - %W and %V are apparently not the same and
`calendar-iso-to-absolute' is closer to %V.

> Maybe just starting the week on Monday does not guarantee that the
> result is an ISO commercial date?

Unless you see some error I am not seeing here, this is probably not a
bug, but my misunderstanding.

-- 
Ihor Radchenko // yantar92,
Org mode maintainer,
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