OpenStruct objects can no longer be used in form helpers

The helpers are checking if the object responds_to?(:message) now which returns false. OpenStruct uses method_missing to add new attributes unless you specify them in new then it generates accessor methods.

<%= form_for OpenStruct.new(:message => ''), :url => ... do |f| %>
  <%= f.text_field :message %>
<% end %>

Works fine.

That's what i needed for lipodrene course too!

Thanks Samuel, but I was wondering why rails 3 forces me to define the attributes specifically. If the object does not respond to the called method, an undefined method error is raised anyhow. So whats the point in calling respond_to in the form helper?

Anyway, I fixed it by monkey-patching OpenStruct#respond_to?

# config/initializers/open_struct_extensions.rb

class OpenStruct

  def respond_to?(symbol, include_private = false)
    true
  end

end

Thanks for the effort and clarification.

Maybe OpenStruct should override respond_to? like above because it responds to all methods, but that does not belong here.