Fix bogus timetz_zone() results for DYNTZ abbreviations.

tglsfdc · tglsfdc · commit d8a266c5e1bd · 2021-09-06T11:29:52.000-04:00
timetz_zone() delivered completely wrong answers if the zone was specified by a dynamic TZ abbreviation, because it failed to account for the difference between the POSIX conventions for field values in struct pg_tm and the conventions used in PG-specific datetime code. As a stopgap fix, just adjust the tm_year and tm_mon fields to match PG conventions. This is fixed in a different way in HEAD (388e71a) but I don't want to back-patch the change of reference point. Discussion: https://postgr.es/m/CAJ7c6TOMG8zSNEZtCn5SPe+cCk3Lfxb71ZaQwT2F4T7PJ_t=KA@mail.gmail.com
diff --git a/src/backend/utils/adt/date.c b/src/backend/utils/adt/date.c
@@ -2832,6 +2832,8 @@ timetz_zone(PG_FUNCTION_ARGS)
 		struct pg_tm *tm;
 
 		tm = pg_localtime(&now, tzp);
+		tm->tm_year += 1900;	/* adjust to PG conventions */
+		tm->tm_mon += 1;
 		tz = DetermineTimeZoneAbbrevOffset(tm, tzname, tzp);
 	}
 	else

Original file line number	Diff line number	Diff line change
`@@ -2832,6 +2832,8 @@ timetz_zone(PG_FUNCTION_ARGS)`
`2832`	`2832`	`struct pg_tm *tm;`
`2833`	`2833`
`2834`	`2834`	`tm = pg_localtime(&now, tzp);`
	`2835`	`+ tm->tm_year += 1900; /* adjust to PG conventions */`
	`2836`	`+ tm->tm_mon += 1;`
`2835`	`2837`	`tz = DetermineTimeZoneAbbrevOffset(tm, tzname, tzp);`
`2836`	`2838`	`}`
`2837`	`2839`	`else`