title: Rails: Association was not found; perhaps you misspelled it?
body: <p>I have a <code>User</code> model with a <code>has_many :through</code> relationship to the <code>Publication</code> model. The <code>Publication</code> model in turn has a <code>has_many :through</code> relationship to <code>Author</code>:</p>
  
  <pre><code>class User &lt; ActiveRecord::Base
    has_many :library_publications, :dependent =&gt; :destroy, :class_name =&gt; "Library::Publication"
    has_many :publications, :through =&gt; :library_publications
  end
  
  class Library::Publication &lt; ActiveRecord::Base
    belongs_to :publication
    belongs_to :user
  end
  
  class Publication &lt; PublicationBase
    has_many :library_publications, :dependent =&gt; :destroy, :class_name =&gt; "Library::Publication"
    has_many :users, :through =&gt; :library_publications
    has_many :publication_contributions, :dependent =&gt; :destroy, :class_name =&gt; "Publication::Contribution"
    has_many :authors, :through =&gt; :publication_contributions
  end
  
  class Author &lt; AuthorBase
    has_many :publication_contributions, :dependent =&gt; :destroy, :class_name =&gt; "Publication::Contribution"
    has_many :publications, :through =&gt; :publication_contributions
  end
  
  class Publication::Contribution &lt; Publication::ContributionBase
    belongs_to :publication, :class_name =&gt; "Publication"
    belongs_to :author, :class_name =&gt; "Author"
  end
  </code></pre>
  
  <p>As far as I can tell, all the associations are written correctly. However, when I try to eagerload authors from a user:</p>
  
  <pre><code>@user.library_publications.includes(:publication =&gt; [:authors])
  </code></pre>
  
  <p>I get this error:</p>
  
  <pre><code>Association named 'authors' was not found; perhaps you misspelled it?
  </code></pre>
  
  <p>What might be the cause of this?</p>