MDEV-38258 No error thrown when CTE columns updated in updates set clause

mysql-test/main/cte_update_delete.result

@@ -1325,5 +1325,23 @@ insert into t3 values (1, 1, 'iron'),(2,2,'wood'),(0,NULL, 'gold'),
 (3, 3, 'silver'), (4, 4, 'lead'), (5, 5, 'tin'), (6, 6, 'platinum'),
 (7, 7, 'aluminium');
 drop prepare s;
+#
+# MDEV-38258 No error thrown when CTE columns updated in updates set clause
+#
+with cte as (select * from t1 where c < 1)
+update cte set cte.a =(select a from cte);
+ERROR HY000: The target table cte of the UPDATE is not updatable
+with cte as (select a from t1)
+update cte set cte.a=(select a from cte limit 1);
+ERROR HY000: The target table cte of the UPDATE is not updatable
+with cte as (select a from t1),
+cte2 as (select a from t3)
+update t2, cte set cte.a=(select a from cte limit 1);
+ERROR HY000: The target table cte of the UPDATE is not updatable
+with cte as (select a from t1),
+cte2 as (select a from t3)
+update cte
+set cte.a=(select a from cte where cte.a in (select a from cte2) limit 1);
+ERROR HY000: The target table cte of the UPDATE is not updatable
 drop table t1, t2, t3, t4, t5;
 # End of 12.2 tests

mysql-test/main/cte_update_delete.test

@@ -511,6 +511,28 @@ eval $empty_t3;
 eval $fill_t3;
 drop prepare s;
 
+--echo #
+--echo # MDEV-38258 No error thrown when CTE columns updated in updates set clause
+--echo #
+
+--error ER_NON_UPDATABLE_TABLE
+with cte as (select * from t1 where c < 1)
+  update cte set cte.a =(select a from cte);
+
+--error ER_NON_UPDATABLE_TABLE
+with cte as (select a from t1)
+  update cte set cte.a=(select a from cte limit 1);
+
+--error ER_NON_UPDATABLE_TABLE
+with cte as (select a from t1),
+  cte2 as (select a from t3)
+  update t2, cte set cte.a=(select a from cte limit 1);
+
+--error ER_NON_UPDATABLE_TABLE
+with cte as (select a from t1),
+  cte2 as (select a from t3)
+  update cte
+   set cte.a=(select a from cte where cte.a in (select a from cte2) limit 1);
 
 drop table t1, t2, t3, t4, t5;
 

sql/table.cc

@@ -10163,6 +10163,9 @@ bool TABLE_LIST::init_derived(THD *thd, bool init_view)
            belong_to_view ? belong_to_view->updating :
                            !unit->outer_select()->outer_select();
 
+    if (with && updating)
+      set_materialized_derived();
+
     /*
        In the case where a table merge operation moves a derived table from
        one select to another, table hints may be adjusted already.