Fix an oversight in the function-default-arguments patch: after adding some

default expressions to a function call, eval_const_expressions must recurse on
those expressions.  Else they don't get simplified, and in particular we fail
to insert additional default arguments if any functions needing defaults are
in there.  Per report from Rushabh Lathia.

src/backend/optimizer/util/clauses.c

@@ -8,7 +8,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/optimizer/util/clauses.c,v 1.273 2009/01/01 17:23:44 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/optimizer/util/clauses.c,v 1.274 2009/01/06 01:23:21 tgl Exp $
  *
  * HISTORY
  *	  AUTHOR			DATE			MAJOR EVENT
@@ -98,7 +98,8 @@ static Expr *simplify_function(Oid funcid,
 				  bool allow_inline,
 				  eval_const_expressions_context *context);
 static List *add_function_defaults(List *args, Oid result_type,
-								   HeapTuple func_tuple);
+								   HeapTuple func_tuple,
+								   eval_const_expressions_context *context);
 static Expr *evaluate_function(Oid funcid,
 				  Oid result_type, int32 result_typmod, List *args,
 				  HeapTuple func_tuple,
@@ -3279,7 +3280,7 @@ simplify_function(Oid funcid, Oid result_type, int32 result_typmod,
 
 	/* While we have the tuple, check if we need to add defaults */
 	if (((Form_pg_proc) GETSTRUCT(func_tuple))->pronargs > list_length(*args))
-		*args = add_function_defaults(*args, result_type, func_tuple);
+		*args = add_function_defaults(*args, result_type, func_tuple, context);
 
 	newexpr = evaluate_function(funcid, result_type, result_typmod, *args,
 								func_tuple, context);
@@ -3302,9 +3303,11 @@ simplify_function(Oid funcid, Oid result_type, int32 result_typmod,
  * just like the parser did.
  */
 static List *
-add_function_defaults(List *args, Oid result_type, HeapTuple func_tuple)
+add_function_defaults(List *args, Oid result_type, HeapTuple func_tuple,
+					  eval_const_expressions_context *context)
 {
 	Form_pg_proc funcform = (Form_pg_proc) GETSTRUCT(func_tuple);
+	int			nargsprovided = list_length(args);
 	Datum		proargdefaults;
 	bool		isnull;
 	char	   *str;
@@ -3327,7 +3330,7 @@ add_function_defaults(List *args, Oid result_type, HeapTuple func_tuple)
 	Assert(IsA(defaults, List));
 	pfree(str);
 	/* Delete any unused defaults from the list */
-	ndelete = list_length(args) + list_length(defaults) - funcform->pronargs;
+	ndelete = nargsprovided + list_length(defaults) - funcform->pronargs;
 	if (ndelete < 0)
 		elog(ERROR, "not enough default arguments");
 	while (ndelete-- > 0)
@@ -3337,8 +3340,8 @@ add_function_defaults(List *args, Oid result_type, HeapTuple func_tuple)
 	Assert(list_length(args) == funcform->pronargs);
 
 	/*
-	 * The rest of this should be a no-op if there are no polymorphic
-	 * arguments, but we do it anyway to be sure.
+	 * The next part should be a no-op if there are no polymorphic arguments,
+	 * but we do it anyway to be sure.
 	 */
 	if (list_length(args) > FUNC_MAX_ARGS)
 		elog(ERROR, "too many function arguments");
@@ -3361,6 +3364,20 @@ add_function_defaults(List *args, Oid result_type, HeapTuple func_tuple)
 	/* perform any necessary typecasting of arguments */
 	make_fn_arguments(NULL, args, actual_arg_types, declared_arg_types);
 
+	/*
+	 * Lastly, we have to recursively simplify the arguments we just added
+	 * (but don't recurse on the ones passed in, as we already did those).
+	 * This isn't merely an optimization, it's *necessary* since there could
+	 * be functions with defaulted arguments down in there.
+	 */
+	foreach(lc, args)
+	{
+		if (nargsprovided-- > 0)
+			continue;			/* skip original arg positions */
+		lfirst(lc) = eval_const_expressions_mutator((Node *) lfirst(lc),
+													context);
+	}
+
 	return args;
 }