bug#6897: date -d '1991-04-14 +1 day' fails

[Paul Eggert]

On 08/24/10 00:23, Voelker, Bernhard wrote:

> BTW: This example looks different here:
> 
>   $ TZ=Pacific/Kwajalein date -d 1993-08-20
>   Sat Aug 21 00:00:00 MHT 1993
> 
>   $ date --version
>   date (GNU coreutils) 8.5
>   Packaged by Cygwin (8.5-2)
>   ...
> 
> Why?

Haven't a clue.  Perhaps you can debug it?  I get the
correct answer (i.e., there was no such date) on both
RHEL 5 with my own-built coreutils 8.5, and with
Ubuntu 10.04 with its standard-issue coreutils 7.4.

> With a normal user's perspective, I'd expect `date` to "just do the job"

Gee, I don't know, all the normal users I know
just want "date" to print the date.

Date arithmetic is pretty esoteric, after all.
What is one month after 31 January, for example?
There's no way this stuff can be done in a way
that is straightforward and satisfies everybody.
I'm becoming more inclined to say that GNU date
shouldn't be doing date arithmetic at all.