Reject year zero during datetime input, except when it's a 2-digit year

tglsfdc · tglsfdc · commit bc93919be787 · 2008-02-25T23:36:28.000Z
(then it means 2000 AD).  Formerly we silently interpreted this as 1 BC,
which at best is unwarranted familiarity with the implementation.
It's barely possible that some app somewhere expects the old behavior,
though, so we won't back-patch this into existing release branches.
diff --git a/src/backend/utils/adt/datetime.c b/src/backend/utils/adt/datetime.c
@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/datetime.c,v 1.186 2008/02/25 23:21:01 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/datetime.c,v 1.187 2008/02/25 23:36:28 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -2138,24 +2138,30 @@ ValidateDate(int fmask, bool is2digits, bool bc, struct pg_tm * tm)
 {
 	if (fmask & DTK_M(YEAR))
 	{
-		/* there is no year zero in AD/BC notation; i.e. "1 BC" == year 0 */
 		if (bc)
 		{
-			if (tm->tm_year > 0)
-				tm->tm_year = -(tm->tm_year - 1);
-			else
-				ereport(ERROR,
-						(errcode(ERRCODE_INVALID_DATETIME_FORMAT),
-						 errmsg("inconsistent use of year %04d and \"BC\"",
-								tm->tm_year)));
+			/* there is no year zero in AD/BC notation */
+			if (tm->tm_year <= 0)
+				return DTERR_FIELD_OVERFLOW;
+			/* internally, we represent 1 BC as year zero, 2 BC as -1, etc */
+			tm->tm_year = -(tm->tm_year - 1);
 		}
 		else if (is2digits)
 		{
+			/* allow 2-digit input for 1970-2069 AD; 00 is allowed */
+			if (tm->tm_year < 0)				/* just paranoia */
+				return DTERR_FIELD_OVERFLOW;
 			if (tm->tm_year < 70)
 				tm->tm_year += 2000;
 			else if (tm->tm_year < 100)
 				tm->tm_year += 1900;
 		}
+		else
+		{
+			/* there is no year zero in AD/BC notation */
+			if (tm->tm_year <= 0)
+				return DTERR_FIELD_OVERFLOW;
+		}
 	}
 
 	/* now that we have correct year, decode DOY */

Original file line number	Diff line number	Diff line change
`@@ -8,7 +8,7 @@`
`8`	`8`	`*`
`9`	`9`	`*`
`10`	`10`	`* IDENTIFICATION`
`11`		`- * $PostgreSQL: pgsql/src/backend/utils/adt/datetime.c,v 1.186 2008/02/25 23:21:01 tgl Exp $`
	`11`	`+ * $PostgreSQL: pgsql/src/backend/utils/adt/datetime.c,v 1.187 2008/02/25 23:36:28 tgl Exp $`
`12`	`12`	`*`
`13`	`13`	`*-------------------------------------------------------------------------`
`14`	`14`	`*/`
`@@ -2138,24 +2138,30 @@ ValidateDate(int fmask, bool is2digits, bool bc, struct pg_tm * tm)`
`2138`	`2138`	`{`
`2139`	`2139`	`if (fmask & DTK_M(YEAR))`
`2140`	`2140`	`{`
`2141`		`- /* there is no year zero in AD/BC notation; i.e. "1 BC" == year 0 */`
`2142`	`2141`	`if (bc)`
`2143`	`2142`	`{`
`2144`		`- if (tm->tm_year > 0)`
`2145`		`- tm->tm_year = -(tm->tm_year - 1);`
`2146`		`- else`
`2147`		`- ereport(ERROR,`
`2148`		`- (errcode(ERRCODE_INVALID_DATETIME_FORMAT),`
`2149`		`- errmsg("inconsistent use of year %04d and \"BC\"",`
`2150`		`- tm->tm_year)));`
	`2143`	`+ /* there is no year zero in AD/BC notation */`
	`2144`	`+ if (tm->tm_year <= 0)`
	`2145`	`+ return DTERR_FIELD_OVERFLOW;`
	`2146`	`+ /* internally, we represent 1 BC as year zero, 2 BC as -1, etc */`
	`2147`	`+ tm->tm_year = -(tm->tm_year - 1);`
`2151`	`2148`	`}`
`2152`	`2149`	`else if (is2digits)`
`2153`	`2150`	`{`
	`2151`	`+ /* allow 2-digit input for 1970-2069 AD; 00 is allowed */`
	`2152`	`+ if (tm->tm_year < 0) /* just paranoia */`
	`2153`	`+ return DTERR_FIELD_OVERFLOW;`
`2154`	`2154`	`if (tm->tm_year < 70)`
`2155`	`2155`	`tm->tm_year += 2000;`
`2156`	`2156`	`else if (tm->tm_year < 100)`
`2157`	`2157`	`tm->tm_year += 1900;`
`2158`	`2158`	`}`
	`2159`	`+ else`
	`2160`	`+ {`
	`2161`	`+ /* there is no year zero in AD/BC notation */`
	`2162`	`+ if (tm->tm_year <= 0)`
	`2163`	`+ return DTERR_FIELD_OVERFLOW;`
	`2164`	`+ }`
`2159`	`2165`	`}`
`2160`	`2166`
`2161`	`2167`	`/* now that we have correct year, decode DOY */`