BUG#17591: Updatable view not possible with trigger or stored function

When a view was used inside a trigger or a function, lock type for
tables used in a view was always set to READ (thus making the view
non-updatable), even if we were trying to update the view.

The solution is to set lock type properly.


mysql-test/r/view.result:
  Add result for bug#17591: Updatable view not possible with trigger
  or stored function.
mysql-test/t/view.test:
  Add test case for bug#17591: Updatable view not possible with trigger
  or stored function.
sql/sql_view.cc:
  Move the code that sets requested lock type before the point where
  we exit from mysql_make_view() when we process a placeholder for
  prelocked table.

mysql-test/r/view.result

@@ -2849,4 +2849,30 @@ SHOW TABLES;
 Tables_in_test
 t1
 DROP TABLE t1;
-DROP VIEW IF EXISTS v1;
+DROP FUNCTION IF EXISTS f1;
+DROP FUNCTION IF EXISTS f2;
+DROP VIEW IF EXISTS v1, v2;
+DROP TABLE IF EXISTS t1;
+CREATE TABLE t1 (i INT);
+CREATE VIEW v1 AS SELECT * FROM t1;
+CREATE FUNCTION f1() RETURNS INT
+BEGIN
+INSERT INTO v1 VALUES (0);
+RETURN 0;
+END |
+SELECT f1();
+f1()
+0
+CREATE ALGORITHM=TEMPTABLE VIEW v2 AS SELECT * FROM t1;
+CREATE FUNCTION f2() RETURNS INT
+BEGIN
+INSERT INTO v2 VALUES (0);
+RETURN 0;
+END |
+SELECT f2();
+ERROR HY000: The target table v2 of the INSERT is not updatable
+DROP FUNCTION f1;
+DROP FUNCTION f2;
+DROP VIEW v1, v2;
+DROP TABLE t1;
+End of 5.0 tests.

mysql-test/t/view.test

@@ -2715,6 +2715,53 @@ DROP VIEW t1,v1;
 SHOW TABLES;
 
 DROP TABLE t1;
+
+
+#
+# BUG#17591: Updatable view not possible with trigger or stored
+# function 
+#
+# During prelocking phase we didn't update lock type of view tables,
+# hence READ lock was always requested.
+#
 --disable_warnings
-DROP VIEW IF EXISTS v1;
+DROP FUNCTION IF EXISTS f1;
+DROP FUNCTION IF EXISTS f2;
+DROP VIEW IF EXISTS v1, v2;
+DROP TABLE IF EXISTS t1;
 --enable_warnings
+
+CREATE TABLE t1 (i INT);
+
+CREATE VIEW v1 AS SELECT * FROM t1;
+
+delimiter |;
+CREATE FUNCTION f1() RETURNS INT
+BEGIN
+  INSERT INTO v1 VALUES (0);
+  RETURN 0;
+END |
+delimiter ;|
+
+SELECT f1();
+
+CREATE ALGORITHM=TEMPTABLE VIEW v2 AS SELECT * FROM t1;
+
+delimiter |;
+CREATE FUNCTION f2() RETURNS INT
+BEGIN
+  INSERT INTO v2 VALUES (0);
+  RETURN 0;
+END |
+delimiter ;|
+
+--error ER_NON_UPDATABLE_TABLE
+SELECT f2();
+
+DROP FUNCTION f1;
+DROP FUNCTION f2;
+DROP VIEW v1, v2;
+DROP TABLE t1;
+
+
+--echo End of 5.0 tests.

sql/sql_view.cc

@@ -1052,6 +1052,31 @@ bool mysql_make_view(THD *thd, File_parser *parser, TABLE_LIST *table)
       table->next_global= view_tables;
     }
 
+    bool view_is_mergeable= (table->algorithm != VIEW_ALGORITHM_TMPTABLE &&
+                             lex->can_be_merged());
+    TABLE_LIST *view_main_select_tables;
+    if (view_is_mergeable)
+    {
+      /*
+        Currently 'view_main_select_tables' differs from 'view_tables'
+        only then view has CONVERT_TZ() function in its select list.
+        This may change in future, for example if we enable merging of
+        views with subqueries in select list.
+      */
+      view_main_select_tables=
+        (TABLE_LIST*)lex->select_lex.table_list.first;
+
+      /*
+        Let us set proper lock type for tables of the view's main
+        select since we may want to perform update or insert on
+        view. This won't work for view containing union. But this is
+        ok since we don't allow insert and update on such views
+        anyway.
+      */
+      for (tbl= view_main_select_tables; tbl; tbl= tbl->next_local)
+        tbl->lock_type= table->lock_type;
+    }
+
     /*
       If we are opening this view as part of implicit LOCK TABLES, then
       this view serves as simple placeholder and we should not continue
@@ -1106,43 +1131,26 @@ bool mysql_make_view(THD *thd, File_parser *parser, TABLE_LIST *table)
       - VIEW SELECT allow merging
       - VIEW used in subquery or command support MERGE algorithm
     */
-    if (table->algorithm != VIEW_ALGORITHM_TMPTABLE &&
-	lex->can_be_merged() &&
+    if (view_is_mergeable &&
         (table->select_lex->master_unit() != &old_lex->unit ||
          old_lex->can_use_merged()) &&
         !old_lex->can_not_use_merged())
     {
-      List_iterator_fast<TABLE_LIST> ti(view_select->top_join_list);
-      /*
-        Currently 'view_main_select_tables' differs from 'view_tables'
-        only then view has CONVERT_TZ() function in its select list.
-        This may change in future, for example if we enable merging
-        of views with subqueries in select list.
-      */
-      TABLE_LIST *view_main_select_tables=
-                    (TABLE_LIST*)lex->select_lex.table_list.first;
       /* lex should contain at least one table */
       DBUG_ASSERT(view_main_select_tables != 0);
 
+      List_iterator_fast<TABLE_LIST> ti(view_select->top_join_list);
+
       table->effective_algorithm= VIEW_ALGORITHM_MERGE;
       DBUG_PRINT("info", ("algorithm: MERGE"));
       table->updatable= (table->updatable_view != 0);
       table->effective_with_check=
         old_lex->get_effective_with_check(table);
       table->merge_underlying_list= view_main_select_tables;
-      /*
-        Let us set proper lock type for tables of the view's main select
-        since we may want to perform update or insert on view. This won't
-        work for view containing union. But this is ok since we don't
-        allow insert and update on such views anyway.
 
-        Also we fill correct wanted privileges.
-      */
-      for (tbl= table->merge_underlying_list; tbl; tbl= tbl->next_local)
-      {
-        tbl->lock_type= table->lock_type;
+      /* Fill correct wanted privileges. */
+      for (tbl= view_main_select_tables; tbl; tbl= tbl->next_local)
         tbl->grant.want_privilege= top_view->grant.orig_want_privilege;
-      }
 
       /* prepare view context */
       lex->select_lex.context.resolve_in_table_list_only(view_main_select_tables);