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

Move table pointer for single table view (even if it is view over other view) to make the access universal.

mysql-test/r/view.result

@@ -5618,6 +5618,20 @@ Warnings:
 Note	1003	select `test`.`t1`.`a` AS `a`,`test`.`t1`.`b` AS `b`,`test`.`t2`.`c` AS `c`,`test`.`t2`.`d` AS `d`,`test`.`t3`.`e` AS `e`,`test`.`t3`.`f` AS `f` from `test`.`t1` left join (`test`.`t2` join `test`.`t3`) on(((`test`.`t2`.`c` = `test`.`t1`.`b`) and (`test`.`t3`.`f` = `test`.`t1`.`a`) and (`test`.`t2`.`d` = `test`.`t3`.`e`) and (`test`.`t1`.`a` is not null) and (`test`.`t1`.`a` is not null) and (`test`.`t1`.`b` is not null))) where (`test`.`t1`.`a` < 5)
 drop view v1;
 drop table t1,t2,t3;
+#
+# MDEV-11240: Server crashes in check_view_single_update or
+# Assertion `derived->table' failed in mysql_derived_merge_for_insert
+#
+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;
 # -----------------------------------------------------------------
 # -- End of 5.5 tests.
 # -----------------------------------------------------------------

mysql-test/t/view.test

@@ -5565,6 +5565,22 @@ select *
 drop view v1;
 drop table t1,t2,t3;
 
+--echo #
+--echo # MDEV-11240: Server crashes in check_view_single_update or
+--echo # Assertion `derived->table' failed in mysql_derived_merge_for_insert
+--echo #
+
+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;
+drop view v1,v2;
+drop table t3;
+
 --echo # -----------------------------------------------------------------
 --echo # -- End of 5.5 tests.
 --echo # -----------------------------------------------------------------

sql/sql_derived.cc

@@ -525,7 +525,9 @@ bool mysql_derived_merge_for_insert(THD *thd, LEX *lex, TABLE_LIST *derived)
       derived->schema_table= derived->merge_underlying_list->schema_table;
       derived->merged_for_insert= TRUE;
     }
-  }  
+  }
+  else
+    derived->table= derived->merge_underlying_list->table;
   DBUG_RETURN(FALSE);
 }