# Association build changed under rails 2.1?

**URL:** <https://www.ruby-forum.com/t/association-build-changed-under-rails-2-1/139998>\
**Category:** Rails\
**Created:** [June 9, 2008, 11:06pm UTC](https://www.ruby-forum.com/t/association-build-changed-under-rails-2-1/139998 "2008-06-09T23:06:20Z")\
**Posts on this page:** 1\
**Page:** 1

<div class="post-metadata">

**Author:** ![rubynuby](https://www.ruby-forum.com/letter_avatar_proxy/v4/letter/r/ba9def/32.png) [@rubynuby](https://www.ruby-forum.com/u/rubynuby)\
**Post date:** [June 9, 2008, 11:06pm UTC](https://www.ruby-forum.com/t/association-build-changed-under-rails-2-1/139998/1 "2008-06-09T23:06:20Z")

</div>

class Post \< ActiveRecord::Base  
has\_many :assets  
end

This used to work fine

self.assets.build(attrs)

but under 2.1 it works sometimes and not others. Don’t know if that  
is because Asset uses attachment\_fu (which I’ve updated to latest)

But this is okay under 2.1

self.assets \<\< Asset.new(attrs)

I’m probably doing something wrong. Which way is, well, wrong\_er\_?