Pass routes via env['action_dispatch.routes'], it's needed by routes to determine if it should generate prefix for mounted apps

3 files changed, 31 insertions, 3 deletions

diff --git a/railties/lib/rails/application.rb b/railties/lib/rails/application.rb
index fee99faf43..4ea828c549 100644
--- a/railties/lib/rails/application.rb
+++ b/railties/lib/rails/application.rb
@@ -125,10 +125,10 @@ module Rails
     end
 
     def env_defaults
-      @env_defaults ||= {
+      @env_defaults ||= super.merge({
         "action_dispatch.parameter_filter" => config.filter_parameters,
         "action_dispatch.secret_token" => config.secret_token
-      }
+      })
     end
 
     def initializers
diff --git a/railties/lib/rails/engine.rb b/railties/lib/rails/engine.rb
index 41b0a764e2..22a1a15bf5 100644
--- a/railties/lib/rails/engine.rb
+++ b/railties/lib/rails/engine.rb
@@ -159,7 +159,13 @@ module Rails
     end
 
     def call(env)
-      app.call(env)
+      app.call(env.reverse_merge!(env_defaults))
+    end
+
+    def env_defaults
+      @env_defaults ||= {
+        "action_dispatch.routes" => routes
+      }
     end
 
     def routes
diff --git a/railties/test/railties/engine_test.rb b/railties/test/railties/engine_test.rb
index e8675daef0..4257a9fa83 100644
--- a/railties/test/railties/engine_test.rb
+++ b/railties/test/railties/engine_test.rb
@@ -177,5 +177,27 @@ module RailtiesTest
 
       assert Bukkits::Engine.config.environment_loaded
     end
+
+    test "it passes router in env" do
+      @plugin.write "lib/bukkits.rb", <<-RUBY
+        class Bukkits
+          class Engine < ::Rails::Engine
+            endpoint lambda { |env| [200, {'Content-Type' => 'text/html'}, 'hello'] }
+          end
+        end
+      RUBY
+
+      boot_rails
+
+      env = Rack::MockRequest.env_for("/")
+      response = Bukkits::Engine.call(env)
+
+      assert_equal Bukkits::Engine.routes, env['action_dispatch.routes']
+
+      env = Rack::MockRequest.env_for("/")
+      response = Rails.application.call(env)
+
+      assert_equal Rails.application.routes, env['action_dispatch.routes']
+    end
   end
 end