Backport of revno: 2617.68.43

Bug #47335 assert in get_table_share

The assert would happen if ALTER VIEW was used to alter a view (existing 
or non-existing) and a temporary table with the same name already existed.

The assert is triggered if the current statement does not have a MDL lock on 
the view to be altered. This would happen because open_table() would open 
the temporary table instead and MDL locks are not taken for temporary 
tables (since they are local to one connection).

The patch changes open_type for CREATE/ALTER VIEW to OT_BASE_ONLY. This prevents 
open_table() from trying to open a temporary table with the same name should
one exist. Now the view will be altered if it exists or ER_NO_SUCH_TABLE will
be reported if it does not.

Test case added to view.test

mysql-test/r/view.result

@@ -3959,3 +3959,20 @@ DROP TABLE t1;
 # -----------------------------------------------------------------
 # -- End of 5.1 tests.
 # -----------------------------------------------------------------
+#
+# Bug #47335 assert in get_table_share
+#
+DROP TABLE IF EXISTS t1;
+DROP VIEW IF EXISTS v1;
+CREATE TEMPORARY TABLE t1 (id INT);
+ALTER VIEW t1 AS SELECT 1 AS f1;
+ERROR 42S02: Table 'test.t1' doesn't exist
+DROP TABLE t1;
+CREATE VIEW v1 AS SELECT 1 AS f1;
+CREATE TEMPORARY TABLE v1 (id INT);
+ALTER VIEW v1 AS SELECT 2 AS f1;
+DROP TABLE v1;
+SELECT * FROM v1;
+f1
+2
+DROP VIEW v1;

mysql-test/t/view.test

@@ -3906,3 +3906,24 @@ DROP TABLE t1;
 --echo # -----------------------------------------------------------------
 --echo # -- End of 5.1 tests.
 --echo # -----------------------------------------------------------------
+
+--echo #
+--echo # Bug #47335 assert in get_table_share
+--echo #
+
+--disable_warnings
+DROP TABLE IF EXISTS t1;
+DROP VIEW IF EXISTS v1;
+--enable_warnings
+
+CREATE TEMPORARY TABLE t1 (id INT);
+--error ER_NO_SUCH_TABLE
+ALTER VIEW t1 AS SELECT 1 AS f1;
+DROP TABLE t1;
+
+CREATE VIEW v1 AS SELECT 1 AS f1;
+CREATE TEMPORARY TABLE v1 (id INT);
+ALTER VIEW v1 AS SELECT 2 AS f1;
+DROP TABLE v1;
+SELECT * FROM v1;
+DROP VIEW v1;

sql/sql_view.cc

@@ -397,6 +397,7 @@ bool mysql_create_view(THD *thd, TABLE_LIST *views,
   lex->link_first_table_back(view, link_to_local);
   view->open_strategy= TABLE_LIST::OPEN_STUB;
   view->lock_strategy= TABLE_LIST::EXCLUSIVE_MDL;
+  view->open_type= OT_BASE_ONLY;
 
   if (open_and_lock_tables(thd, lex->query_tables))
   {