Clear url helper methods when routes are reloaded

Remove all the old url helper methods when clear! is called on the
route set because it's possible that some routes have been removed.

4 files changed, 165 insertions, 0 deletions

diff --git a/actionpack/CHANGELOG.md b/actionpack/CHANGELOG.md
index 521b9b6835..31822f1eda 100644
--- a/actionpack/CHANGELOG.md
+++ b/actionpack/CHANGELOG.md
@@ -1,5 +1,7 @@
 ## Rails 4.0.0 (unreleased) ##
 
+*   Clear url helper methods when routes are reloaded. *Andrew White*
+
 *   Fix a bug in ActionDispatch::Request#raw_post that caused env['rack.input']
     to be read but not rewound.
 
diff --git a/actionpack/lib/action_dispatch/routing/route_set.rb b/actionpack/lib/action_dispatch/routing/route_set.rb
index 61071d1228..c11e66d110 100644
--- a/actionpack/lib/action_dispatch/routing/route_set.rb
+++ b/actionpack/lib/action_dispatch/routing/route_set.rb
@@ -130,6 +130,12 @@ module ActionDispatch
         end
 
         def clear!
+          @helpers.each do |helper|
+            @module.module_eval do
+              remove_possible_method helper
+            end
+          end
+
           @routes.clear
           @helpers.clear
         end
diff --git a/actionpack/test/dispatch/routing/route_set_test.rb b/actionpack/test/dispatch/routing/route_set_test.rb
new file mode 100644
index 0000000000..d57b1a5637
--- /dev/null
+++ b/actionpack/test/dispatch/routing/route_set_test.rb
@@ -0,0 +1,86 @@
+require 'abstract_unit'
+
+module ActionDispatch
+  module Routing
+    class RouteSetTest < ActiveSupport::TestCase
+      class SimpleApp
+        def initialize(response)
+          @response = response
+        end
+
+        def call(env)
+          [ 200, { 'Content-Type' => 'text/plain' }, [response] ]
+        end
+      end
+
+      setup do
+        @set = RouteSet.new
+      end
+
+      test "url helpers are added when route is added" do
+        draw do
+          get 'foo', to: SimpleApp.new('foo#index')
+        end
+
+        assert_equal '/foo', url_helpers.foo_path
+        assert_raises NoMethodError do
+          assert_equal '/bar', url_helpers.bar_path
+        end
+
+        draw do
+          get 'foo', to: SimpleApp.new('foo#index')
+          get 'bar', to: SimpleApp.new('bar#index')
+        end
+
+        assert_equal '/foo', url_helpers.foo_path
+        assert_equal '/bar', url_helpers.bar_path
+      end
+
+      test "url helpers are updated when route is updated" do
+        draw do
+          get 'bar', to: SimpleApp.new('bar#index'), as: :bar
+        end
+
+        assert_equal '/bar', url_helpers.bar_path
+
+        draw do
+          get 'baz', to: SimpleApp.new('baz#index'), as: :bar
+        end
+
+        assert_equal '/baz', url_helpers.bar_path
+      end
+
+      test "url helpers are removed when route is removed" do
+        draw do
+          get 'foo', to: SimpleApp.new('foo#index')
+          get 'bar', to: SimpleApp.new('bar#index')
+        end
+
+        assert_equal '/foo', url_helpers.foo_path
+        assert_equal '/bar', url_helpers.bar_path
+
+        draw do
+          get 'foo', to: SimpleApp.new('foo#index')
+        end
+
+        assert_equal '/foo', url_helpers.foo_path
+        assert_raises NoMethodError do
+          assert_equal '/bar', url_helpers.bar_path
+        end
+      end
+
+      private
+        def clear!
+          @set.clear!
+        end
+
+        def draw(&block)
+          @set.draw(&block)
+        end
+
+        def url_helpers
+          @set.url_helpers
+        end
+    end
+  end
+end
diff --git a/railties/test/application/routing_test.rb b/railties/test/application/routing_test.rb
index 3691ad2723..22de640236 100644
--- a/railties/test/application/routing_test.rb
+++ b/railties/test/application/routing_test.rb
@@ -277,6 +277,77 @@ module ApplicationTests
       end
     end
 
+    test 'routes are added and removed when reloading' do
+      app('development')
+
+      controller :foo, <<-RUBY
+        class FooController < ApplicationController
+          def index
+            render text: "foo"
+          end
+        end
+      RUBY
+
+      controller :bar, <<-RUBY
+        class BarController < ApplicationController
+          def index
+            render text: "bar"
+          end
+        end
+      RUBY
+
+      app_file 'config/routes.rb', <<-RUBY
+        AppTemplate::Application.routes.draw do
+          get 'foo', to: 'foo#index'
+        end
+      RUBY
+
+      get '/foo'
+      assert_equal 'foo', last_response.body
+      assert_equal '/foo', Rails.application.routes.url_helpers.foo_path
+
+      get '/bar'
+      assert_equal 404, last_response.status
+      assert_raises NoMethodError do
+        assert_equal '/bar', Rails.application.routes.url_helpers.bar_path
+      end
+
+      app_file 'config/routes.rb', <<-RUBY
+        AppTemplate::Application.routes.draw do
+          get 'foo', to: 'foo#index'
+          get 'bar', to: 'bar#index'
+        end
+      RUBY
+
+      Rails.application.reload_routes!
+
+      get '/foo'
+      assert_equal 'foo', last_response.body
+      assert_equal '/foo', Rails.application.routes.url_helpers.foo_path
+
+      get '/bar'
+      assert_equal 'bar', last_response.body
+      assert_equal '/bar', Rails.application.routes.url_helpers.bar_path
+
+      app_file 'config/routes.rb', <<-RUBY
+        AppTemplate::Application.routes.draw do
+          get 'foo', to: 'foo#index'
+        end
+      RUBY
+
+      Rails.application.reload_routes!
+
+      get '/foo'
+      assert_equal 'foo', last_response.body
+      assert_equal '/foo', Rails.application.routes.url_helpers.foo_path
+
+      get '/bar'
+      assert_equal 404, last_response.status
+      assert_raises NoMethodError do
+        assert_equal '/bar', Rails.application.routes.url_helpers.bar_path
+      end
+    end
+
     test 'resource routing with irregular inflection' do
       app_file 'config/initializers/inflection.rb', <<-RUBY
         ActiveSupport::Inflector.inflections do |inflect|