Routing with a blank path_prefix causes a bad url to generate

It appears ticket #1571 Routing with empty path_prefix should not add two / to the url is about the same problem.

I'm not sure I follow why you're passing an empty string there though? Seems wrong to just silently ignore a value that was passed?

The blank string came when trying to build routes like this:

path_prefix = (%w(development test).include?(RAILS_ENV) ? "admin" : "") map.namespace(:admin, :path_prefix => path_prefix) do |admin|

...

end

Yes, it could easily by fixed by making the conditional return nil instead of "", but it still seems like adding the / when there is no slug isn't appropriate.

path_prefix = (%w(development test).include?(RAILS_ENV) ? "admin" : "") 
map.namespace(:admin, :path_prefix => path_prefix) do |admin|
    ...
end

(can we get a preview function on comments before posting them?)

I'm +1 on this. We've had two different people hit this, the fixed behavior seems reasonably intuitive and I can't think of anything else we'd want to do with an empty :path_prefix.