2 files changed, 1 insertions, 2 deletions
diff --git a/actionpack/lib/action_dispatch/routing/route_set.rb b/actionpack/lib/action_dispatch/routing/route_set.rb
index 4289e78641..66b487ba6d 100644
--- a/actionpack/lib/action_dispatch/routing/route_set.rb
+++ b/actionpack/lib/action_dispatch/routing/route_set.rb
@@ -318,7 +318,7 @@ module ActionDispatch
               singleton_class.send(:define_method, :_routes) { routes }
             end
 
-            define_method(:_routes) { @_routes || routes }
+            define_method(:_routes) { @_routes ||= nil; @_routes || routes }
           end
 
           helpers
diff --git a/actionpack/lib/action_dispatch/routing/url_for.rb b/actionpack/lib/action_dispatch/routing/url_for.rb
index 045c9ec77d..e836cf7c8e 100644
--- a/actionpack/lib/action_dispatch/routing/url_for.rb
+++ b/actionpack/lib/action_dispatch/routing/url_for.rb
@@ -128,7 +128,6 @@ module ActionDispatch
         when String
           options
         when nil, Hash
-          @_routes ||= nil
           _routes.url_for((options || {}).reverse_merge!(url_options).symbolize_keys)
         else
           polymorphic_url(options)