Fix incorrect Datum conversion in timestamptz_trunc_internal()

michaelpq · michaelpq · commit 074db8604ad1 · 2025-08-07T11:02:09.000+09:00
The code used a PG_RETURN_TIMESTAMPTZ() where the return type is TimestampTz and not a Datum. On 64-bit systems, there is no effect since this just ends up casting 64-bit integers back and forth. On 32-bit systems, timestamptz is pass-by-reference. PG_RETURN_TIMESTAMPTZ() allocates new memory and returns the address, meaning that the caller could interpret this as a timestamp value. The effect is using "date_trunc(..., 'infinity'::timestamptz) will return random values (instead of the correct return value 'infinity'). Bug introduced in commit d85ce01. Author: Peter Eisentraut <peter@eisentraut.org> Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://postgr.es/m/2d320b6f-b4af-4fbc-9eec-5d0fa15d187b@eisentraut.org Discussion: https://postgr.es/m/4bf60a84-2862-4a53-acd5-8eddf134a60e@eisentraut.org Backpatch-through: 18
diff --git a/src/backend/utils/adt/timestamp.c b/src/backend/utils/adt/timestamp.c
@@ -4954,7 +4954,7 @@ timestamptz_trunc_internal(text *units, TimestampTz timestamp, pg_tz *tzp)
 				case DTK_SECOND:
 				case DTK_MILLISEC:
 				case DTK_MICROSEC:
-					PG_RETURN_TIMESTAMPTZ(timestamp);
+					return timestamp;
 					break;
 
 				default:
