升级了，ruby.taobao.org 现在很重要。。

:plus1:

大家升级 4.1.2 或 4.0.6 后如果 HABTM 的 collection 计算结果有问题的话请联系我：

4.1.2:

Fixed has_and_belongs_to_many's CollectionAssociation size calculation.

has_and_belongs_to_many should fall back to using the normal CollectionAssociation's size calculation if the collection is not cached or loaded.

Fixes #14913, #14914.

Fred Wu

https://github.com/rails/rails/blob/4-1-stable/activerecord/CHANGELOG.md

4.0.6:

Fixed has_and_belongs_to_many's CollectionAssociation size calculation.

has_and_belongs_to_many should not include new records as part of #count_records as new records are already counted.

Fixes #14914.

Fred Wu

https://github.com/rails/rails/blob/4-0-stable/activerecord/CHANGELOG.md

#3 楼 @fredwu 厉害

has_and_belongs_to_many 现在是不是用 has_many through 替代了

#3 楼 @fredwu 想问一下 rails 4.0 运行在 ruby 2.1 上会有问题吗？

@huacnlee http://guides.ruby-china.org/ 为什么这个取消啦？