Bug#28266 IS_UPDATABLE field on VIEWS table in I_S database is wrong

IS_UPDATABLE flag is set to 'yes' when the view has at least one updatable column and
the algorithm is not 'temporary'.

mysql-test/r/information_schema.result

@@ -1315,3 +1315,14 @@ TABLE_PRIVILEGES	information_schema.TABLE_PRIVILEGES	1
 TRIGGERS	information_schema.TRIGGERS	1
 USER_PRIVILEGES	information_schema.USER_PRIVILEGES	1
 VIEWS	information_schema.VIEWS	1
+create table t1(f1 int);
+create view v1 as select f1+1 as a from t1;
+create table t2 (f1 int, f2 int);
+create view v2 as select f1+1 as a, f2 as b from t2;
+select table_name, is_updatable from information_schema.views;
+table_name	is_updatable
+v1	NO
+v2	YES
+delete from v1;
+drop view v1,v2;
+drop table t1,t2;

mysql-test/r/view.result

@@ -23,6 +23,9 @@ c
 5
 6
 11
+select is_updatable from information_schema.views where table_name='v1';
+is_updatable
+NO
 create temporary table t1 (a int, b int);
 select * from t1;
 a	b
@@ -322,6 +325,12 @@ create table t1 (a int, b int, primary key(a));
 insert into t1 values (10,2), (20,3), (30,4), (40,5), (50,10);
 create view v1 (a,c) as select a, b+1 from t1;
 create algorithm=temptable view v2 (a,c) as select a, b+1 from t1;
+select is_updatable from information_schema.views where table_name='v2';
+is_updatable
+NO
+select is_updatable from information_schema.views where table_name='v1';
+is_updatable
+YES
 update v1 set c=a+c;
 ERROR HY000: Column 'c' is not updatable
 update v2 set a=a+c;
@@ -604,6 +613,10 @@ insert into t1 values(5,'Hello, world of views');
 create view v1 as select * from t1;
 create view v2 as select * from v1;
 update v2 set col2='Hello, view world';
+select is_updatable from information_schema.views;
+is_updatable
+YES
+YES
 select * from t1;
 col1	col2
 5	Hello, view world

mysql-test/t/information_schema.test

@@ -1023,4 +1023,19 @@ where t.table_schema = 'information_schema' and
           group by c2.column_type order by num limit 1)
 group by t.table_name order by num1, t.table_name;
 
+#
+# Bug#28266 IS_UPDATABLE field on VIEWS table in I_S database is wrong
+#
+create table t1(f1 int);
+create view v1 as select f1+1 as a from t1;
+create table t2 (f1 int, f2 int);                                                         
+create view v2 as select f1+1 as a, f2 as b from t2;                                      
+select table_name, is_updatable from information_schema.views;
+#
+# Note: we can perform 'delete' for non updatable view.
+#
+delete from v1;
+drop view v1,v2;
+drop table t1,t2;
+
 # End of 5.0 tests.

mysql-test/t/view.test

@@ -32,6 +32,7 @@ create view v1 (c,d) as select a,b from t1
 # simple view
 create view v1 (c) as select b+1 from t1;
 select c from v1;
+select is_updatable from information_schema.views where table_name='v1';
 
 # temporary table should not hide table of view
 create temporary table t1 (a int, b int);
@@ -228,6 +229,8 @@ create table t1 (a int, b int, primary key(a));
 insert into t1 values (10,2), (20,3), (30,4), (40,5), (50,10);
 create view v1 (a,c) as select a, b+1 from t1;
 create algorithm=temptable view v2 (a,c) as select a, b+1 from t1;
+select is_updatable from information_schema.views where table_name='v2';
+select is_updatable from information_schema.views where table_name='v1';
 # try to update expression
 -- error 1348
 update v1 set c=a+c;
@@ -497,6 +500,7 @@ insert into t1 values(5,'Hello, world of views');
 create view v1 as select * from t1;
 create view v2 as select * from v1;
 update v2 set col2='Hello, view world';
+select is_updatable from information_schema.views;
 select * from t1;
 drop view v2, v1;
 drop table t1;

sql/sql_show.cc

@@ -3158,6 +3158,7 @@ static int get_schema_views_record(THD *thd, struct st_table_list *tables,
   DBUG_ENTER("get_schema_views_record");
   char definer[USER_HOST_BUFF_SIZE];
   uint definer_len;
+  bool updatable_view;
 
   if (tables->view)
   {
@@ -3195,7 +3196,34 @@ static int get_schema_views_record(THD *thd, struct st_table_list *tables,
     else
       table->field[4]->store(STRING_WITH_LEN("NONE"), cs);
 
-    if (tables->updatable_view)
+    updatable_view= 0;
+    if (tables->algorithm != VIEW_ALGORITHM_TMPTABLE)
+    {
+      /*
+        We should use tables->view->select_lex.item_list here and
+        can not use Field_iterator_view because the view always uses
+        temporary algorithm during opening for I_S and
+        TABLE_LIST fields 'field_translation' & 'field_translation_end'
+        are uninitialized is this case.
+      */
+      List<Item> *fields= &tables->view->select_lex.item_list;
+      List_iterator<Item> it(*fields);
+      Item *item;
+      Item_field *field;
+      /*
+        chech that at least one coulmn in view is updatable
+      */
+      while ((item= it++))
+      {
+        if ((field= item->filed_for_view_update()) && field->field &&
+            !field->field->table->pos_in_table_list->schema_table)
+        {
+          updatable_view= 1;
+          break;
+        }
+      }
+    }
+    if (updatable_view)
       table->field[5]->store(STRING_WITH_LEN("YES"), cs);
     else
       table->field[5]->store(STRING_WITH_LEN("NO"), cs);