Create a new expression node type RelabelType, which exists solely to

represent the result of a binary-compatible type coercion.  At runtime
it just evaluates its argument --- but during type resolution, exprType
will pick up the output type of the RelabelType node instead of the type
of the argument.  This solves some longstanding problems with dropped
type coercions, an example being 'select now()::abstime::int4' which
used to produce date-formatted output, not an integer, because the
coercion to int4 was dropped on the floor.

1 files changed, 17 insertions, 1 deletions

diff --git a/src/backend/nodes/outfuncs.c b/src/backend/nodes/outfuncs.c
index c40ca9ff9cb..db785afab9f 100644
--- a/src/backend/nodes/outfuncs.c
+++ b/src/backend/nodes/outfuncs.c
@@ -6,7 +6,7 @@
  * Portions Copyright (c) 1996-2000, PostgreSQL, Inc
  * Portions Copyright (c) 1994, Regents of the University of California
  *
- *	$Header: /cvsroot/pgsql/src/backend/nodes/outfuncs.c,v 1.108 2000/02/15 20:49:09 tgl Exp $
+ *	$Header: /cvsroot/pgsql/src/backend/nodes/outfuncs.c,v 1.109 2000/02/20 21:32:05 tgl Exp $
  *
  * NOTES
  *	  Every (plan) node in POSTGRES has an associated "out" routine which
@@ -771,6 +771,19 @@ _outSubLink(StringInfo str, SubLink *node)
 }
 
 /*
+ *	RelabelType
+ */
+static void
+_outRelabelType(StringInfo str, RelabelType *node)
+{
+	appendStringInfo(str, " RELABELTYPE :arg ");
+	_outNode(str, node->arg);
+
+	appendStringInfo(str, " :resulttype %u :resulttypmod %d ",
+					 node->resulttype, node->resulttypmod);
+}
+
+/*
  *	Array is a subclass of Expr
  */
 static void
@@ -1496,6 +1509,9 @@ _outNode(StringInfo str, void *obj)
 			case T_SubLink:
 				_outSubLink(str, obj);
 				break;
+			case T_RelabelType:
+				_outRelabelType(str, obj);
+				break;
 			case T_Array:
 				_outArray(str, obj);
 				break;