Rails 3 : How to disable autosave of has_one and has_many associations?

i have a user model which has one image. how can i disable the autosave option. when i tried the following i am getting an error. Am using rails 3.

class User &开发者_如何学编程lt; ActiveRecord::Base  
  has_one :image_mapping, :class_name=>"ImageMapping",:as => :imageable  
  has_one :image, :through => :image_mapping, :class_name => "Image", :autosave => false  
end  

It says Unknown key(s): autosave

isn't loading autosave_association.rb properly?

This probably doesn't solve your problem, but perhaps you find it helpful anyway:

There seems to be a problem with has_one :through. For example in class Post,

has_one :owner, :through => :blog

works fine, but

has_one :owner, :through => :blog, :autosave => false

doesn't. If you instantiate a Post, like so

post = Post.find 1

you get this:

ArgumentError: Unknown key(s): autosave
    from /var/lib/gems/1.9.1/gems/activesupport-3.0.1/lib/active_support/core_ext/hash/keys.rb:43:in `assert_valid_keys'
    from /var/lib/gems/1.9.1/gems/activerecord-3.0.1/lib/active_record/associations.rb:1758:in `create_has_one_through_reflection'
    from /var/lib/gems/1.9.1/gems/activerecord-3.0.1/lib/active_record/associations.rb:1102:in `has_one'
    from /var/lib/gems/1.9.1/gems/activerecord-3.0.1/lib/active_record/autosave_association.rb:137:in `has_one'
[...] 

Looking at the documentation, I can't find a reason why it shouldn't work. And in fact it seems to work fine with has_many, only has_one hiccups if the :autosave option is set.

Unless somebody here on Stack Overflow finds something wrong with using :has_one in this way, you could also go to the Rails mailing list for help; I think Rails-core is the right one for this problem.

If you wish to assign an object to a has_one association without saving it, use the build_association method. The object being replaced will still be saved to update its foreign key.

Example

user = User.new
user.build_image