Fix problems with rewriter failing to set Query.hasSubLinks when inserting

a SubLink expression into a rule query.  Pre-8.1 we essentially did this
unconditionally; 8.1 tries to do it only when needed, but was missing a
couple of cases.  Per report from Kyle Bateman.  Add some regression test
cases covering this area.

src/backend/rewrite/rewriteHandler.c

@@ -7,7 +7,7 @@
  * Portions Copyright (c) 1994, Regents of the University of California
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/rewrite/rewriteHandler.c,v 1.159 2005/11/22 18:17:19 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/rewrite/rewriteHandler.c,v 1.160 2005/11/23 17:21:03 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -374,6 +374,14 @@ rewriteRuleAction(Query *parsetree,
 
 			sub_action->jointree->fromlist =
 				list_concat(newjointree, sub_action->jointree->fromlist);
+
+			/*
+			 * There could have been some SubLinks in newjointree, in which
+			 * case we'd better mark the sub_action correctly.
+			 */
+			if (parsetree->hasSubLinks && !sub_action->hasSubLinks)
+				sub_action->hasSubLinks =
+					checkExprHasSubLink((Node *) newjointree);
 		}
 	}
 

src/backend/rewrite/rewriteManip.c

@@ -7,7 +7,7 @@
  *
  *
  * IDENTIFICATION
- *	  $PostgreSQL: pgsql/src/backend/rewrite/rewriteManip.c,v 1.93 2005/11/22 18:17:19 momjian Exp $
+ *	  $PostgreSQL: pgsql/src/backend/rewrite/rewriteManip.c,v 1.94 2005/11/23 17:21:03 tgl Exp $
  *
  *-------------------------------------------------------------------------
  */
@@ -930,6 +930,7 @@ ResolveNew(Node *node, int target_varno, int sublevels_up,
 		   RangeTblEntry *target_rte,
 		   List *targetlist, int event, int update_varno)
 {
+	Node	   *result;
 	ResolveNew_context context;
 
 	context.target_varno = target_varno;
@@ -944,8 +945,21 @@ ResolveNew(Node *node, int target_varno, int sublevels_up,
 	 * Must be prepared to start with a Query or a bare expression tree; if
 	 * it's a Query, we don't want to increment sublevels_up.
 	 */
-	return query_or_expression_tree_mutator(node,
+	result = query_or_expression_tree_mutator(node,
 											  ResolveNew_mutator,
 											  (void *) &context,
 											  0);
+
+	if (context.inserted_sublink)
+	{
+		if (IsA(result, Query))
+			((Query *) result)->hasSubLinks = true;
+		/*
+		 * Note: if we're called on a non-Query node then it's the caller's
+		 * responsibility to update hasSubLinks in the ancestor Query.
+		 * This is pretty fragile and perhaps should be rethought ...
+		 */
+	}
+
+	return result;
 }

src/test/regress/expected/subselect.out

@@ -334,3 +334,55 @@ SELECT * FROM orders_view;
 DROP TABLE orderstest cascade;
 NOTICE:  drop cascades to rule _RETURN on view orders_view
 NOTICE:  drop cascades to view orders_view
+--
+-- Test cases to catch situations where rule rewriter fails to propagate
+-- hasSubLinks flag correctly.  Per example from Kyle Bateman.
+--
+create temp table parts (
+    partnum     text,
+    cost        float8
+);
+create temp table shipped (
+    ttype       char(2),
+    ordnum      int4,
+    partnum     text,
+    value       float8
+);
+create temp view shipped_view as
+    select * from shipped where ttype = 'wt';
+create rule shipped_view_insert as on insert to shipped_view do instead
+    insert into shipped values('wt', new.ordnum, new.partnum, new.value);
+insert into parts (partnum, cost) values (1, 1234.56);
+insert into shipped_view (ordnum, partnum, value)
+    values (0, 1, (select cost from parts where partnum = 1));
+select * from shipped_view;
+ ttype | ordnum | partnum |  value  
+-------+--------+---------+---------
+ wt    |      0 | 1       | 1234.56
+(1 row)
+
+create rule shipped_view_update as on update to shipped_view do instead
+    update shipped set partnum = new.partnum, value = new.value
+        where ttype = new.ttype and ordnum = new.ordnum;
+update shipped_view set value = 11
+    from int4_tbl a join int4_tbl b
+      on (a.f1 = (select f1 from int4_tbl c where c.f1=b.f1))
+    where ordnum = a.f1;
+select * from shipped_view;
+ ttype | ordnum | partnum | value 
+-------+--------+---------+-------
+ wt    |      0 | 1       |    11
+(1 row)
+
+select f1, ss1 as relabel from
+    (select *, (select sum(f1) from int4_tbl b where f1 >= a.f1) as ss1
+     from int4_tbl a) ss;
+     f1      |  relabel   
+-------------+------------
+           0 | 2147607103
+      123456 | 2147607103
+     -123456 | 2147483647
+  2147483647 | 2147483647
+ -2147483647 |          0
+(5 rows)
+

src/test/regress/sql/subselect.sql

@@ -191,3 +191,48 @@ FROM orderstest ord;
 SELECT * FROM orders_view;
 
 DROP TABLE orderstest cascade;
+
+--
+-- Test cases to catch situations where rule rewriter fails to propagate
+-- hasSubLinks flag correctly.  Per example from Kyle Bateman.
+--
+
+create temp table parts (
+    partnum     text,
+    cost        float8
+);
+
+create temp table shipped (
+    ttype       char(2),
+    ordnum      int4,
+    partnum     text,
+    value       float8
+);
+
+create temp view shipped_view as
+    select * from shipped where ttype = 'wt';
+
+create rule shipped_view_insert as on insert to shipped_view do instead
+    insert into shipped values('wt', new.ordnum, new.partnum, new.value);
+
+insert into parts (partnum, cost) values (1, 1234.56);
+
+insert into shipped_view (ordnum, partnum, value)
+    values (0, 1, (select cost from parts where partnum = 1));
+
+select * from shipped_view;
+
+create rule shipped_view_update as on update to shipped_view do instead
+    update shipped set partnum = new.partnum, value = new.value
+        where ttype = new.ttype and ordnum = new.ordnum;
+
+update shipped_view set value = 11
+    from int4_tbl a join int4_tbl b
+      on (a.f1 = (select f1 from int4_tbl c where c.f1=b.f1))
+    where ordnum = a.f1;
+
+select * from shipped_view;
+
+select f1, ss1 as relabel from
+    (select *, (select sum(f1) from int4_tbl b where f1 >= a.f1) as ss1
+     from int4_tbl a) ss;