Clean up the code for to_timestamp's conversion of year plus ISO day number

to date, as per bug #4702 and subsequent discussion.  In particular, make it
work for years specified using AD/BC or CC fields, and fix the test for "no
year specified" so that it doesn't trigger inappropriately for 1 BC (which it
was doing even in code paths that had nothing to do with to_timestamp).  I
also did some minor code beautification in the non-ISO-day-number code path.

This area has been busted all along, but because the code has been rewritten
repeatedly, it would be considerable trouble to back-patch.  It's such a
corner case that it doesn't seem worth the effort.

1 files changed, 1 insertions, 6 deletions

diff --git a/src/backend/utils/adt/timestamp.c b/src/backend/utils/adt/timestamp.c
index 06eb044f0c5..2d1e7ff45ae 100644
--- a/src/backend/utils/adt/timestamp.c
+++ b/src/backend/utils/adt/timestamp.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/timestamp.c,v 1.196 2009/01/01 17:23:50 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/timestamp.c,v 1.197 2009/03/15 20:31:19 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -3668,11 +3668,6 @@ isoweek2j(int year, int week)
 	int			day0,
 				day4;
 
-	if (!year)
-		ereport(ERROR,
-				(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
-		   errmsg("cannot calculate week number without year information")));
-
 	/* fourth day of current year */
 	day4 = date2j(year, 1, 4);