Use env['action_dispatch.routes'] to determine if we should generate prefix or not.

This technique is here to allow using routes from Engine in Application
and vice versa. When using Engine routes inside Application it should
generate prefix based on mount point. When using Engine routes inside
Engine it should use env['SCRIPT_NAME']. In any other case it should
generate prefix as env should not be even available.

1 files changed, 7 insertions, 1 deletions

diff --git a/actionpack/lib/action_dispatch/routing/url_for.rb b/actionpack/lib/action_dispatch/routing/url_for.rb
index 28ec830fe8..f73067688c 100644
--- a/actionpack/lib/action_dispatch/routing/url_for.rb
+++ b/actionpack/lib/action_dispatch/routing/url_for.rb
@@ -128,7 +128,13 @@ module ActionDispatch
         when String
           options
         when nil, Hash
-          _routes.url_for((options || {}).reverse_merge!(url_options).symbolize_keys)
+          routes = (options ? options.delete(:routes) : nil) || _routes
+
+          if respond_to?(:env) && env && routes.equal?(env["action_dispatch.routes"])
+             options[:skip_prefix] = true
+          end
+
+          routes.url_for((options || {}).reverse_merge!(url_options).symbolize_keys)
         else
           polymorphic_url(options)
         end