Fixed LP bug #794038.

INSERT/UPDATE/DELETE statement that used a temptable view v1 could lead to
a crash if v1 was defined as a select from a mergeable view v2 that selected
rows from a temptable view v3. 
 
When INSERT/UPDATE/DELETE uses a view that is not updatable then field
translation for the view should be created before the prepare phase.

mysql-test/r/view.result

@@ -4168,3 +4168,19 @@ a	a	b
 2	2	30
 DROP VIEW v2;
 DROP TABLE t1,t2;
+#
+# Bug#794038: crash  with INSERT/UPDATE/DELETE 
+#             over a non-updatable view
+#
+CREATE TABLE t1 (a int);
+CREATE ALGORITHM = TEMPTABLE VIEW v1 AS SELECT * FROM t1;
+CREATE ALGORITHM = MERGE VIEW v2 AS SELECT * FROM v1;
+CREATE ALGORITHM = TEMPTABLE VIEW v3 AS SELECT * FROM v2;
+INSERT INTO v3 VALUES (1);
+ERROR HY000: The target table v3 of the INSERT is not insertable-into
+UPDATE v3 SET a=0;
+ERROR HY000: The target table v3 of the UPDATE is not updatable
+DELETE FROM v3;
+ERROR HY000: The target table v3 of the DELETE is not updatable
+DROP VIEW v1,v2,v3;
+DROP TABLE t1;

mysql-test/t/view.test

@@ -4114,3 +4114,23 @@ SELECT * FROM t1,v2
 
 DROP VIEW v2;
 DROP TABLE t1,t2;
+
+--echo #
+--echo # Bug#794038: crash  with INSERT/UPDATE/DELETE 
+--echo #             over a non-updatable view
+--echo #
+
+CREATE TABLE t1 (a int);
+CREATE ALGORITHM = TEMPTABLE VIEW v1 AS SELECT * FROM t1;
+CREATE ALGORITHM = MERGE VIEW v2 AS SELECT * FROM v1;
+CREATE ALGORITHM = TEMPTABLE VIEW v3 AS SELECT * FROM v2;
+
+-- error ER_NON_INSERTABLE_TABLE
+INSERT INTO v3 VALUES (1);
+-- error ER_NON_UPDATABLE_TABLE
+UPDATE v3 SET a=0;
+-- error ER_NON_UPDATABLE_TABLE
+DELETE FROM v3;
+
+DROP VIEW v1,v2,v3;
+DROP TABLE t1;

sql/sql_derived.cc

@@ -467,6 +467,12 @@ bool mysql_derived_merge_for_insert(THD *thd, LEX *lex, TABLE_LIST *derived)
 
   if (derived->merged_for_insert)
     return FALSE;
+  /* It's a target view for an INSERT, create field translation only. */
+  if (!derived->updatable || derived->is_materialized_derived())
+  {
+    bool res= derived->create_field_translation(thd);
+    return res;
+  }
   if (!derived->is_multitable())
   {
     TABLE_LIST *tl=((TABLE_LIST*)dt_select->table_list.first);
@@ -603,16 +609,9 @@ bool mysql_derived_prepare(THD *thd, LEX *lex, TABLE_LIST *derived)
   bool res= FALSE;
 
   // Skip already prepared views/DT
-  if (!unit || unit->prepared)
+  if (!unit || unit->prepared || derived->merged_for_insert)
     DBUG_RETURN(FALSE);
 
-  /* It's a target view for an INSERT, create field translation only. */
-  if (derived->merged_for_insert)
-  {
-    res= derived->create_field_translation(thd);
-    DBUG_RETURN(res);
-  }
-
   Query_arena *arena= thd->stmt_arena, backup;
   if (arena->is_conventional())
     arena= 0;                                   // For easier test

sql/sql_parse.cc

@@ -2697,9 +2697,6 @@ mysql_execute_command(THD *thd)
             }
           }
         }
-        if (mysql_handle_single_derived(thd->lex, create_table,
-            DT_MERGE_FOR_INSERT))
-          DBUG_RETURN(1);
 
         /* So that CREATE TEMPORARY TABLE gets to binlog at commit/rollback */
         if (create_info.options & HA_LEX_CREATE_TMP_TABLE)