When we added the ability to have zero-element ARRAY[] constructs by adding an

explicit cast to show the intended array type, we forgot to teach ruleutils.c
to print out such constructs properly.  Found by noting bogus output from
recent changes in polymorphism regression test.

src/backend/utils/adt/ruleutils.c

@@ -9,7 +9,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.289 2008/12/18 18:20:34 tgl Exp $
+ *	  $PostgreSQL: pgsql/src/backend/utils/adt/ruleutils.c,v 1.290 2008/12/19 05:04:35 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -4451,6 +4451,14 @@ get_rule_expr(Node *node, deparse_context *context,
 				appendStringInfo(buf, "ARRAY[");
 				get_rule_expr((Node *) arrayexpr->elements, context, true);
 				appendStringInfoChar(buf, ']');
+				/*
+				 * If the array isn't empty, we assume its elements are
+				 * coerced to the desired type.  If it's empty, though, we
+				 * need an explicit coercion to the array type.
+				 */
+				if (arrayexpr->elements == NIL)
+					appendStringInfo(buf, "::%s",
+						format_type_with_typemod(arrayexpr->array_typeid, -1));
 			}
 			break;
 

src/test/regress/expected/polymorphism.out

@@ -1007,8 +1007,8 @@ HINT:  Use DROP FUNCTION first.
 \df dfunc
                                   List of functions
  Schema | Name  | Result data type |               Argument data types               
---------+-------+------------------+--------------------------------------
- public | dfunc | integer          | VARIADIC a integer[] DEFAULT ARRAY[]
+--------+-------+------------------+-------------------------------------------------
+ public | dfunc | integer          | VARIADIC a integer[] DEFAULT ARRAY[]::integer[]
 (1 row)
 
 drop function dfunc(a variadic int[]);