Trouble on setting the ':controller' parameter for a 'link_to' statement - ruby-on-rails

Question

I am using Ruby on Rails 3.0.9 and I would like to know why I get the error described below and how can I solve that.
In my /views/articles/categories/_content.html.erb file I have:
...
<%= link_to("New article", {:controller => content[:article_controller], :action => 'new'}) %>
...
If I set the content[:article_controller] to (both setting true and false for the :only_path option)
1. content[:article_controller] = 'articles'
2. content[:article_controller] = '/articles'
3. content[:article_controller] = '/articles/'
4. content[:article_controller] = '/'
4. content[:article_controller] = ''
I get respectively the following errors (note :controller values):
1. `ActionView::Template::Error (No route matches {:controller=>"articles/categories/articles", :action=>"new"})`
2. `ActionView::Template::Error (No route matches {:controller=>"articles//articles", :action=>"new"})`
3. `ActionView::Template::Error (No route matches {:controller=>"articles/", :action=>"new"})`
4. `ActionView::Template::Error (No route matches {:controller=>"articles//", :action=>"new"})`
4. `ActionView::Template::Error (No route matches {:controller=>"articles/categories/", :action=>"new"})`
Is it a Ruby on Rails bug or is it my fault? What is the problem and how can I solve that making the link_to properly work?
However I can solve that problem by using:
<%= link_to("New article", {:controller => '../', :action => 'new'}) %>
But why it works with '.../' but not in other ways?
I noticed that some time the controller path for which I try to set the content[:article_contr8oller] seems to relying on the "base" current controller path that is handling the view file (the controller file is app/controllers/articles/categories/concerns_controller.rb - read below for more information)... why it happens?
It also happens using url_for:
url_for(:controller => 'articles', :action => 'new')
Running the rake routes command I get the following:
articles_categories GET /articles/categories(.:format) {:action=>"index", :controller=>"articles/categories"}
POST /articles/categories(.:format) {:action=>"create", :controller=>"articles/categories"}
new_articles_category GET /articles/categories/new(.:format) {:action=>"new", :controller=>"articles/categories"}
edit_articles_category GET /articles/categories/:id/edit(.:format) {:action=>"edit", :controller=>"articles/categories"}
articles_category GET /articles/categories/:id(.:format) {:action=>"show", :controller=>"articles/categories"}
PUT /articles/categories/:id(.:format) {:action=>"update", :controller=>"articles/categories"}
DELETE /articles/categories/:id(.:format) {:action=>"destroy", :controller=>"articles/categories"}
articles GET /articles(.:format) {:action=>"index", :controller=>"articles"}
POST /articles(.:format) {:action=>"create", :controller=>"articles"}
new_article GET /articles/new(.:format) {:action=>"new", :controller=>"articles"}
edit_article GET /articles/:id/edit(.:format) {:action=>"edit", :controller=>"articles"}
article GET /articles/:id(.:format) {:action=>"show", :controller=>"articles"}
PUT /articles/:id(.:format) {:action=>"update", :controller=>"articles"}
DELETE /articles/:id(.:format) {:action=>"destroy", :controller=>"articles"}
P.S.: If you need more information, let me know and I will update the question as well.
UPDATE I
In my route file I have:
namespace :articles do articles :categories end
scope :path => 'articles/categories/:id', :controller => 'articles/categories/concerns' do
...
end
resources :articles
UPDATE II
In my view /views/articles/categories/_content.html.erb files I have:
<div class="links">
<%= link_to("New article", {:controller => content[:article_controller], :action => 'new'}) %>
</div>
In my Articles::Categories::ConcernsController (that is, in the app/controllers/articles/categories/concerns_controller.rb file) I have:
def show
#articles_category = Articles::Category.find(params[:id])
respond_to do |format|
format.html {
render :partial => '/views/articles/categories/_content.html.erb',
:locals => {
:content => {
:article_controller => '/articles'
}
}
format.js {
...
end
end
end

Answer 1

Did you try using symbols? I think they are more "direct".
<%= link_to("New article", {:controller => content[:article_controller].to_sym, :action => :new}) %>
Did you try using a relativ path?
<%= link_to("New article", {:controller => "../#{content[:article_controller]}", :action => 'new'}) %>

Answer 2

Why aren't you using link_to 'New article', new_article_path? Why use the old, tired url_for ... when you can use the named path/url helper (new_article_url).