Throw an error for negative LIMIT or OFFSET values, instead of silently

treating them as zero.  Simon Riggs

src/backend/executor/nodeLimit.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/executor/nodeLimit.c,v 1.33 2008/01/01 19:45:49 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/executor/nodeLimit.c,v 1.34 2008/03/10 03:37:59 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -246,7 +246,9 @@ recompute_limits(LimitState *node)
 		{
 			node->offset = DatumGetInt64(val);
 			if (node->offset < 0)
-				node->offset = 0;
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+						 errmsg("OFFSET must not be negative")));
 		}
 	}
 	else
@@ -271,7 +273,9 @@ recompute_limits(LimitState *node)
 		{
 			node->count = DatumGetInt64(val);
 			if (node->count < 0)
-				node->count = 0;
+				ereport(ERROR,
+						(errcode(ERRCODE_INVALID_PARAMETER_VALUE),
+						 errmsg("LIMIT must not be negative")));
 			node->noCount = false;
 		}
 	}