Eagerly build the routing helper module after routes are committed

This commit eagerly builds the route helper module after the routes have
been drawn and finalized.  This allows us to cache the helper module but
not have to worry about people accessing the module while route
definition is "in-flight", and automatically deals with cache
invalidation as the module is regenerated anytime someone redraws the
routes.

The restriction this commit introduces is that the url helper module can
only be accessed *after* the routes are done being drawn.

Refs #24554 and #32892

4 files changed, 18 insertions, 13 deletions

diff --git a/actionpack/test/abstract_unit.rb b/actionpack/test/abstract_unit.rb
index 65dd28b3d7..7c9f15108d 100644
--- a/actionpack/test/abstract_unit.rb
+++ b/actionpack/test/abstract_unit.rb
@@ -100,7 +100,10 @@ end
 
 class ActionDispatch::IntegrationTest < ActiveSupport::TestCase
   def self.build_app(routes = nil)
-    RoutedRackApp.new(routes || ActionDispatch::Routing::RouteSet.new) do |middleware|
+    routes ||= ActionDispatch::Routing::RouteSet.new.tap { |rs|
+      rs.draw { }
+    }
+    RoutedRackApp.new(routes) do |middleware|
       middleware.use ActionDispatch::ShowExceptions, ActionDispatch::PublicExceptions.new("#{FIXTURE_LOAD_PATH}/public")
       middleware.use ActionDispatch::DebugExceptions
       middleware.use ActionDispatch::Callbacks
diff --git a/actionpack/test/controller/integration_test.rb b/actionpack/test/controller/integration_test.rb
index 39ede1442a..b078e8ad9f 100644
--- a/actionpack/test/controller/integration_test.rb
+++ b/actionpack/test/controller/integration_test.rb
@@ -542,9 +542,6 @@ class IntegrationProcessTest < ActionDispatch::IntegrationTest
     def with_test_route_set
       with_routing do |set|
         controller = ::IntegrationProcessTest::IntegrationController.clone
-        controller.class_eval do
-          include set.url_helpers
-        end
 
         set.draw do
           get "moved" => redirect("/method")
@@ -555,6 +552,10 @@ class IntegrationProcessTest < ActionDispatch::IntegrationTest
           end
         end
 
+        controller.class_eval do
+          include set.url_helpers
+        end
+
         singleton_class.include(set.url_helpers)
 
         yield
diff --git a/actionpack/test/dispatch/routing/ipv6_redirect_test.rb b/actionpack/test/dispatch/routing/ipv6_redirect_test.rb
index 31559bffc7..fb423d2951 100644
--- a/actionpack/test/dispatch/routing/ipv6_redirect_test.rb
+++ b/actionpack/test/dispatch/routing/ipv6_redirect_test.rb
@@ -4,6 +4,11 @@ require "abstract_unit"
 
 class IPv6IntegrationTest < ActionDispatch::IntegrationTest
   Routes = ActionDispatch::Routing::RouteSet.new
+  Routes.draw do
+    get "/",    to: "bad_route_request#index", as: :index
+    get "/foo", to: "bad_route_request#foo", as: :foo
+  end
+
   include Routes.url_helpers
 
   class ::BadRouteRequestController < ActionController::Base
@@ -17,11 +22,6 @@ class IPv6IntegrationTest < ActionDispatch::IntegrationTest
     end
   end
 
-  Routes.draw do
-    get "/",    to: "bad_route_request#index", as: :index
-    get "/foo", to: "bad_route_request#foo", as: :foo
-  end
-
   def _routes
     Routes
   end
diff --git a/actionpack/test/dispatch/url_generation_test.rb b/actionpack/test/dispatch/url_generation_test.rb
index aef9351de1..b0096d26be 100644
--- a/actionpack/test/dispatch/url_generation_test.rb
+++ b/actionpack/test/dispatch/url_generation_test.rb
@@ -4,16 +4,13 @@ require "abstract_unit"
 
 module TestUrlGeneration
   class WithMountPoint < ActionDispatch::IntegrationTest
-    Routes = ActionDispatch::Routing::RouteSet.new
-    include Routes.url_helpers
-
     class ::MyRouteGeneratingController < ActionController::Base
-      include Routes.url_helpers
       def index
         render plain: foo_path
       end
     end
 
+    Routes = ActionDispatch::Routing::RouteSet.new
     Routes.draw do
       get "/foo", to: "my_route_generating#index", as: :foo
 
@@ -22,6 +19,10 @@ module TestUrlGeneration
       mount MyRouteGeneratingController.action(:index), at: "/bar"
     end
 
+    class ::MyRouteGeneratingController
+      include Routes.url_helpers
+    end
+
     APP = build_app Routes
 
     def _routes