Re: BUG #16419: wrong parsing BC year in to_date() function

Specifically:

/*
 * There is no 0 AD.  Years go from 1 BC to 1 AD, so we make it
 * positive and map year == -1 to year zero, and shift all negative
 * years up one.  For interval years, we just return the year.
 */

#define ADJUST_YEAR(year, is_interval) ((is_interval) ? (year) : ((year) <= 0 ? -((year) - 1) : (year)))

The code comment took me a bit to process - seems like the following would be better (if its right - I don't know why interval is a pure no-op while non-interval normalizes to a positive integer).

Years go from 1 BC to 1 AD, so we adjust the year zero, and all negative years, by shifting them away one year,  We then return the positive value of the result because the caller tracks the BC/AD aspect of the year separately and only deals with positive year values coming out of this macro.  Intervals denote the distance away from 0 a year is so we can simply take the supplied value and return it.  Interval processing code expects a negative result for intervals going into BC.

David J.