Can't destroy object for version 6.0.0

[xiaohui-zhangxh]

Please see below output, am I missing something to configure model?

module Catalog
  class Menu < ActiveRecord::Base
    acts_as_tree dependent: :destroy
  end
end

2.2.1 :002 > Catalog::Menu.find(4).destroy
  Catalog::Menu Load (0.4ms)  SELECT  `catalog_menus`.* FROM `catalog_menus` WHERE `catalog_menus`.`id` = 4 LIMIT 1
   (0.2ms)  BEGIN
   (0.3ms)  SELECT GET_LOCK('ClosureTree::Catalog::Menu', 0) AS t457e5acb1b089fcf2c797b4a5f36d844
   (12.3ms)  DELETE FROM `catalog_menu_hierarchies`
WHERE descendant_id IN (
  SELECT DISTINCT descendant_id
  FROM (SELECT descendant_id
    FROM `catalog_menu_hierarchies`
    WHERE ancestor_id = 4
       OR descendant_id = 4
  ) AS x )

   (0.3ms)  SELECT RELEASE_LOCK('ClosureTree::Catalog::Menu') AS t5d47f4adccd01cbd21808d1b3cb19864
   (5.3ms)  ROLLBACK
ActiveRecord::StatementInvalid: Mysql2::Error: You can't specify target table 'catalog_menu_hierarchies' for update in FROM clause: DELETE FROM `catalog_menu_hierarchies`
WHERE descendant_id IN (
  SELECT DISTINCT descendant_id
  FROM (SELECT descendant_id
    FROM `catalog_menu_hierarchies`
    WHERE ancestor_id = 4
       OR descendant_id = 4
  ) AS x )

[xiaohui-zhangxh]

Ok, I found the solution by my self. This error happens if MySQL is 5.7+, SET optimizer_switch = 'derived_merge=off' can get rid of error. or set my.cnf
optimizer_switch=derived_merge=off under [mysqld] section.

This is where I get the solution: http://stackoverflow.com/questions/32528773/mysql-5-5-to-5-7-you-cant-specify-target-table-for-update-in-from-clause-sa

[mceachen]

Thanks for sharing the solution!

[mceachen]

Added reference in the readme.