unchanged attribute is changed [ActiveModel]

works for me ! It(Ticket) seems invalid ..

I tried this in console as well.

Maybe I'm missing something, but I don't think the test from the diff should pass, using the example implementation from Dirty. The attribute_will_change! method says to Dirty that it will change, so it adds the attribute name and value to @changed_attributes@, which is used by attribute_changed? to determine if it's been changed or not, using changed_attributes.include?(attr).

It seems to me it's up to the implementer to decide when an attribute changes or not, and in the example class a change is recorded every time name= is called. Maybe the examples were copied from when this was part of ActiveRecord, where the test would pass AFAIK.

I think Tore is right. By calling name_will_change! in Person#name=, it's already decided that the attribute has changed.

If this is the desired behavior, which I think is a good idea, then the API docs need to be fixed.

Calling attr_will_change! accordingly is fine but I don't think there is a method that marks a attribute or the entire object as clean.

So how do I tell AMo that the object is now clean in my save method? That is, all the pending changes have been applied so that model.changed? #=> false. I'm guessing it can be done by changing the @changed_attributes map manually.

Would be useful to do will_be_clean! and maybe even attr_will_be_clean!.

It looks like ARec does this.. From http://github.com/rails/rails/blob/master/activerecord/lib/active_record/attribute_methods/dirty.rb#L23:

     def save(*) #:nodoc:
        if status = super
          @previously_changed = changes
          @changed_attributes.clear
        end
        status
      end

The API docs: http://edgeapi.rubyonrails.org/classes/ActiveModel/Dirty.html are pretty misleading. The given examples don't work on the example class given. And they won't work unless the user adds more code. 'Save' and 'Assigning the same value leaves the attribute unchanged' don't work for ex.

Should the example Person class be beefed up to support the examples? Or should the non-working examples be removed?

Also how about providing convenience methods like clear_changes! for @changed_attributes.clear and archive_changes! for @previously_changed = changes? Maybe even a archive_and_clear_changes! for doing both in one shot.

Attaching a patch which fixes the docs and adds a few more tests.

Left out the original issue from the patch, but this should include it..

Patch no longer applies, could you please rebase? Thanks!

Changed.

Jose, any reason why this is not going into 3.0? It's not changing the API, only fixing the docs and adding some more tests.