MDEV-11240: Server crashes in check_view_single_update or Assertion...

MDEV-11240: Server crashes in check_view_single_update or Assertion `derived->table' failed in mysql_derived_merge_for_insert

Before "merge" view shoud be inited to maintaing transitive attributes like "multitable".

mysql-test/r/view.result

@@ -5674,9 +5674,6 @@ CREATE TABLE t3 (a INT);
 CREATE ALGORITHM = MERGE VIEW v1 AS SELECT t2.a FROM t3 AS t1, t3 AS t2;
 CREATE ALGORITHM = MERGE VIEW v2 AS SELECT * FROM v1;
 PREPARE stmt FROM 'REPLACE INTO v2 SELECT a FROM t3';
-EXECUTE stmt;
-ERROR HY000: Can not insert into join view 'test.v2' without fields list
-EXECUTE stmt;
 ERROR HY000: Can not insert into join view 'test.v2' without fields list
 drop view v1,v2;
 drop table t3;

mysql-test/t/view.test

@@ -5577,11 +5577,8 @@ drop table t1,t2,t3;
 CREATE TABLE t3 (a INT);
 CREATE ALGORITHM = MERGE VIEW v1 AS SELECT t2.a FROM t3 AS t1, t3 AS t2;
 CREATE ALGORITHM = MERGE VIEW v2 AS SELECT * FROM v1;
-PREPARE stmt FROM 'REPLACE INTO v2 SELECT a FROM t3';
---error ER_VIEW_NO_INSERT_FIELD_LIST
-EXECUTE stmt;
 --error ER_VIEW_NO_INSERT_FIELD_LIST
-EXECUTE stmt;
+PREPARE stmt FROM 'REPLACE INTO v2 SELECT a FROM t3';
 drop view v1,v2;
 drop table t3;
 

sql/sql_derived.cc

@@ -520,6 +520,8 @@ bool mysql_derived_merge_for_insert(THD *thd, LEX *lex, TABLE_LIST *derived)
                       derived->merge_underlying_list != 0));
   if (derived->merged_for_insert)
     DBUG_RETURN(FALSE);
+  if (derived->init_derived(thd, FALSE))
+    DBUG_RETURN(TRUE);
   if (derived->is_materialized_derived())
     DBUG_RETURN(mysql_derived_prepare(thd, lex, derived));
   if ((thd->lex->sql_command == SQLCOM_UPDATE_MULTI ||
@@ -537,8 +539,6 @@ bool mysql_derived_merge_for_insert(THD *thd, LEX *lex, TABLE_LIST *derived)
       DBUG_ASSERT(derived->table);
     }
   }
-  else
-    derived->table= derived->merge_underlying_list->table;
   DBUG_RETURN(FALSE);
 }