Re: BUG #6126: CC parameter in to_char() behaves incorrectly

On Sat, Aug  4, 2012 at 10:34:14AM -0400, Bruce Momjian wrote:
> > I am thinking it is too late to apply this for 9.2 because users might
> > have already tested their applications, though I doubt many are using BC
> > dates.  Feedback?
>
> There is never just one bug in formatting.c --- the input side was also
> broken for BC/negative centuries.  The attached patch fixes the input
> side as well, and shows the old/fixed output for BC centuries.  The test
> queries were:
>
>     SELECT to_date('-6  4', 'CC YY');
>     SELECT to_date(' 6  4', 'CC YY');
>     SELECT to_date('-6 00', 'CC YY');
>     SELECT to_date(' 6 00', 'CC YY');
>     SELECT to_date('-6', 'CC');
>     SELECT to_date(' 6', 'CC');
>
> I believe this is all for 9.3-only.

OK, I found another bug in our code;  the output of:

  SELECT to_date(' 6 BC', 'CC BC');

returned 501BC, instead of the start of the century, 600BC, like SELECT
to_date('-6', 'CC') does.

I also allowed negative BC dates to map to AD dates, just like negative
AD dates map to BC dates.

Attached is an updated patch and output diff.

--
  Bruce Momjian  <bruce@momjian.us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

  + It's impossible for everything to be true. +