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

@@ -1005,10 +1005,10 @@ $$ select array_upper($1, 1) $$ language sql;
 ERROR:  cannot remove parameter defaults from existing function
 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[]
+                                  List of functions
+ Schema | Name  | Result data type |               Argument data types               
+--------+-------+------------------+-------------------------------------------------
+ public | dfunc | integer          | VARIADIC a integer[] DEFAULT ARRAY[]::integer[]
 (1 row)
 
 drop function dfunc(a variadic int[]);