Merge pull request #5242 from rails/opt_routes

Optimize routes generation in simple cases.

If you pass to the route helper the same amount of arguments
as the required segments, route generation will be optimized
as a string interpolation. After this commit, `post_path(post)`
is about 6.5 times faster, `post_url(post)` is about 5 times.

1 files changed, 5 insertions, 1 deletions

diff --git a/actionpack/lib/action_dispatch/routing/mapper.rb b/actionpack/lib/action_dispatch/routing/mapper.rb
index 02a27110e4..80fcdab643 100644
--- a/actionpack/lib/action_dispatch/routing/mapper.rb
+++ b/actionpack/lib/action_dispatch/routing/mapper.rb
@@ -446,7 +446,11 @@ module ActionDispatch
             _route = @set.named_routes.routes[name.to_sym]
             _routes = @set
             app.routes.define_mounted_helper(name)
-            app.routes.class_eval do
+            app.routes.singleton_class.class_eval do
+              define_method :mounted? do
+                true
+              end
+
               define_method :_generate_prefix do |options|
                 prefix_options = options.slice(*_route.segment_keys)
                 # we must actually delete prefix segment keys to avoid passing them to next url_for