Rails weird default routing behaviour in nested namespace in resource - ruby-on-rails

Question

I have this in my router.rb:
namespace :me do
namespace :bills do
get :consumption_invoice, :format => :pdf
end
end
and also
resources :groups do
member do
namespace :bills do
get :consumption_invoice, :format => :pdf
end
end
end
The first one gives me:
me_bills_consumption_invoice GET /me/bills/consumption_invoice(.:format) me/bills#consumption_invoice {:format=>:pdf}
consumption_invoice_bills_group GET /groups/:id/bills/consumption_invoice(.:format) bills/groups#consumption_invoice {:format=>:pdf}
In the group, the controller called is bills/groups#consumption_invoice instead of groups/bills#consumption_invoice as I'd expect.
Why?
Thanks
EDIT
After some reflexion, here's what I'd like to achieve:
/me/bills/consumption_invoice => :controller => :bills, :action => :consumption_invoice
# and
/groups/:id/bills/consumption_invoice => :controller => :bills, :action => :consumption_invoice
Idealy, I'd like to have both those rules in the :me namespace and the :groups resource blocks for making it cleaner to read.
And I'd like to be able to add more actions easily:
/me/bills/subscription_invoice => :controller => :bills, :action => :subscription_invoice
which is why I wanted to create a block :bills in it.
I've been trying so many possibilities around, can't I achieve that?

Answer 1

The way paths are constructed is different than the way the controller is determined.
Controllers can be organized under a namespace. The namespace is a folder that controllers can sit in. Although the order of resources and namespaces affects the order of the parts of the path, it won't affect the way that namespaces are treated as a controller grouping. The resource is :groups so the controller is named "groups" and handles actions made against the group model. The namespace is :bills so the controller is contained within a folder called "bills".
In a similar fashion, if you nested two resources like:
resources :groups do
resources :users
end
The path for a user action would be /groups/:id/users but the controller would just be named "users".
If you really want this action to be handled by a bills controller in a groups folder, then you could customize the behavior with something like:
resources :groups do
member do
scope module: 'groups' do
get 'bills/consumption_invoice', :format => :pdf, controller: 'bills'
end
end
end
Additional Info for Edit in the Question
If you just want your two paths to reach the bills#consumption_invoice action and you don't want your bills controller to live in a folder called me, you could consider something like this:
get 'me/bills/consumption_invoice', :format => :pdf, to: 'bills#consumption_invoice'
resources :groups do
member do
get 'bills/consumption_invoice', :format => :pdf, controller: 'bills'
end
end
Rails will then expect that your consumption_invoice view lives in a bills folder.
The Rails Routing from the Outside In (http://guides.rubyonrails.org/routing.html) can provide additional details on all the routing options.