Ruby on rails 当回调返回false时，Rails3将删除me HABTM记录

我有这个模型：

class User < ActiveRecord::Base
  has_and_belongs_to_many :roles

  before_destroy do |u|
    if u.superadmin? and User.joins(:roles).where(:roles => {:superadmin => true}).count == 1
      u.errors.add(:base, "cannot delete last admin user")
      return false
    end
    return true
  end
end

class Role < ActiveRecord::Base
  has_and_belongs_to_many :users
end

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感谢您的帮助。

如果您使用较旧的rails版本，这似乎是rails的错误（应该在rails 3.0.6 AFAIK中解决）：

我看到很多网络“内容”表明返回false并不像人们期望的那样。同样的消息来源表明，在before过滤器中重定向或渲染是解决这个问题的“Rails方式”，尽管我对此没有意见。另外，在块中使用“return”语句是一个非常糟糕的主意。谢谢

SQL (0.2ms)  SELECT COUNT(*) FROM "users" INNER JOIN "roles_users" ON "roles_users"."user_id" = "users"."id" INNER JOIN "roles" ON "roles"."id" = "roles_users"."role_id" WHERE "roles"."superadmin" = 't'
AREL (0.4ms)  DELETE FROM "roles_users" WHERE "roles_users"."user_id" = 1 AND "roles_users"."role_id" IN (1, 4)
Organization Load (0.4ms)  SELECT * FROM "organizations" INNER JOIN "organizations_users" ON "organizations".id = "organizations_users".organization_id WHERE ("organizations_users".user_id = 1 )