[Development] Two-digit dates: what century should we use ?

[André Pönitz]

On Wed, Nov 06, 2019 at 12:38:48PM +0000, Edward Welbourne wrote:
> want.  Sample options:
> * keep 1900-1999, discourage use of ShortFormat;
> * rolling window based on currentDate(), as I described earlier;
> * we update startYear's default with each major release of Qt.

First option seems to be the one least surprising.

> For the last, for example, we could make startYear=1940 in Qt6; by the
> time we get to a major release in the late '20s, we'd be ready to move
> that to startYear=1950.  I guess we can be confident of at least one
> major release per not much more than a decade, which suffices to ensure
> that dates throughout the supported life-time of that release do
> round-trip, while reaching well into the past.  That's assuming
> range=100: if we use a buffer zone, range=90 for example, we'd probably
> want Qt6 using startYear=1950 already (so '40s are invalid and '30s are
> the 2030s).
> 
> Any objections to this revised plan ?
> Anyone want to make the case for keeping 1900--1999 as default ?

You mentioned other systems that used that approach.

I would expect interacting with such systems is easiest, if the rules
are the same.

A shifting window would probably be unique to Qt, i.e. cause friction
in all cases.

> Or for my earlier dynamic floating-window proposal ?
> Or any other suggestions for the default ?
> If not, the update at major release - a.k.a. static floating-window -
> looks the sanest to me.

Andre'