Fix for Bug#34337: Server crash when Altering a view using

a table name.
  
The problem was that fill_defined_view_parts() did not return
an error if a table is going to be altered. That happened if
the table was already in the table cache. In that case,
open_table() returned non-NULL value (valid TABLE-instance from
the cache).
  
The fix is to ensure that an error is thrown even if the table
is in the cache.

(This is a backport of the original patch for 5.1)

mysql-test/r/view.result

@@ -3618,4 +3618,23 @@ ERROR HY000: Field of view 'test.v1' underlying table doesn't have a default val
 set @@sql_mode=@old_mode;
 drop view v1;
 drop table t1;
-End of 5.0 tests.
+# -----------------------------------------------------------------
+# -- Bug#34337: Server crash when Altering a view using a table name.
+# -----------------------------------------------------------------
+
+DROP TABLE IF EXISTS t1;
+
+CREATE TABLE t1(c1 INT);
+
+SELECT * FROM t1;
+c1
+ALTER ALGORITHM=TEMPTABLE SQL SECURITY INVOKER VIEW t1 (c2) AS SELECT (1);
+ERROR HY000: 'test.t1' is not VIEW
+
+DROP TABLE t1;
+
+# -- End of test case for Bug#34337.
+
+# -----------------------------------------------------------------
+# -- End of 5.0 tests.
+# -----------------------------------------------------------------

mysql-test/r/view_grant.result

@@ -467,6 +467,7 @@ use test;
 REVOKE ALL PRIVILEGES, GRANT OPTION FROM mysqltest_1@localhost;
 drop database mysqltest;
 drop view if exists v1;
+drop table if exists t1;
 create table t1 as select * from mysql.user where user='';
 delete from mysql.user where user='';
 flush privileges;

mysql-test/t/view.test

@@ -3470,5 +3470,39 @@ insert into v1 values(1);
 set @@sql_mode=@old_mode;
 drop view v1;
 drop table t1;
---echo End of 5.0 tests.
 
+###########################################################################
+
+--echo # -----------------------------------------------------------------
+--echo # -- Bug#34337: Server crash when Altering a view using a table name.
+--echo # -----------------------------------------------------------------
+--echo
+
+--disable_warnings
+DROP TABLE IF EXISTS t1;
+--enable_warnings
+
+--echo
+
+CREATE TABLE t1(c1 INT);
+
+--echo
+
+SELECT * FROM t1;
+
+--error ER_WRONG_OBJECT
+ALTER ALGORITHM=TEMPTABLE SQL SECURITY INVOKER VIEW t1 (c2) AS SELECT (1);
+
+--echo
+
+DROP TABLE t1;
+
+--echo
+--echo # -- End of test case for Bug#34337.
+--echo
+
+###########################################################################
+
+--echo # -----------------------------------------------------------------
+--echo # -- End of 5.0 tests.
+--echo # -----------------------------------------------------------------

mysql-test/t/view_grant.test

@@ -608,6 +608,7 @@ drop database mysqltest;
 #
 --disable_warnings
 drop view if exists v1;
+drop table if exists t1;
 --enable_warnings
 
 # Backup anonymous users and remove them. (They get in the way of

sql/sql_view.cc

@@ -182,10 +182,33 @@ fill_defined_view_parts (THD *thd, TABLE_LIST *view)
   TABLE_LIST decoy;
 
   memcpy (&decoy, view, sizeof (TABLE_LIST));
-  if (!open_table(thd, &decoy, thd->mem_root, &not_used, OPEN_VIEW_NO_PARSE) &&
-      !decoy.view)
+
+  /*
+    Let's reset decoy.view before calling open_table(): when we start
+    supporting ALTER VIEW in PS/SP that may save us from a crash.
+  */
+
+  decoy.view= NULL;
+
+  /*
+    open_table() will return NULL if 'decoy' is idenitifying a view *and*
+    there is no TABLE object for that view in the table cache. However,
+    decoy.view will be set to 1.
+
+    If there is a TABLE-instance for the oject identified by 'decoy',
+    open_table() will return that instance no matter if it is a table or
+    a view.
+
+    Thus, there is no need to check for the return value of open_table(),
+    since the return value itself does not mean anything.
+  */
+
+  open_table(thd, &decoy, thd->mem_root, &not_used, OPEN_VIEW_NO_PARSE);
+
+  if (!decoy.view)
   {
-    /* It's a table */
+    /* It's a table. */
+    my_error(ER_WRONG_OBJECT, MYF(0), view->db, view->table_name, "VIEW");
     return TRUE;
   }