Respect locale set by controller in the failure app

A common usage of I18n with different locales is to create some around
callbcak in the application controller that sets the locale for the
entire action, via params/url/user/etc., which ensure the locale is
respected for the duration of that action, and resets at the end.

Devise was not respecting the locale when the authenticate failed and
triggered the failure app, because that happens in a warden middleware
right up in the change, by that time the controller around callback had
already reset the locale back to its default, and the failure app would
just translate flash messages using the default locale.

Now we are passing the current locale down to the failure app via warden
options, and wrapping it with an around callback, which makes the
failure app respect the set I18n locale by the controller at the time
the authentication failure is triggered, working as expected. (much more
like a normal controller would.)

I chose to introduce a callback in the failure app so we could wrap the
whole `respond` action processing rather than adding individual `locale`
options to the `I18n.t` calls, because that should ensure other possible
`I18n.t` calls from overridden failure apps would respect the set locale
as well, and makes it more like one would implement in a controller. I
don't recommend people using callbacks in their own failure apps though,
as this is not going to be documented as a "feature" of failures apps,
it's considered "internal" and could be refactored at any point.

It is possible to override the locale with the new `i18n_locale` method,
which simply defaults to the passed locale from the controller.

Closes #5247
Closes #5246

Related to: #3052, #4823, and possible others already closed.
Related to warden: (may be closed there afterwards)
wardencommunity/warden#180
wardencommunity/warden#170

app/controllers/devise/sessions_controller.rb

@@ -45,7 +45,7 @@ def serialize_options(resource)
   end
 
   def auth_options
-    { scope: resource_name, recall: "#{controller_path}#new" }
+    { scope: resource_name, recall: "#{controller_path}#new", locale: I18n.locale }
   end
 
   def translation_scope

lib/devise/controllers/helpers.rb

@@ -46,6 +46,7 @@ def authenticate_#{group_name}!(favorite = nil, opts = {})
                 mappings.unshift mappings.delete(favorite.to_sym) if favorite
                 mappings.each do |mapping|
                   opts[:scope] = mapping
+                  opts[:locale] = I18n.locale
                   warden.authenticate!(opts) if !devise_controller? || opts.delete(:force)
                 end
               end
@@ -115,6 +116,7 @@ def self.define_helpers(mapping) #:nodoc:
         class_eval <<-METHODS, __FILE__, __LINE__ + 1
           def authenticate_#{mapping}!(opts = {})
             opts[:scope] = :#{mapping}
+            opts[:locale] = I18n.locale
             warden.authenticate!(opts) if !devise_controller? || opts.delete(:force)
           end
 

lib/devise/failure_app.rb

@@ -18,6 +18,11 @@ class FailureApp < ActionController::Metal
 
     delegate :flash, to: :request
 
+    include AbstractController::Callbacks
+    around_action do |failure_app, action|
+      I18n.with_locale(failure_app.i18n_locale, &action)
+    end
+
     def self.call(env)
       @respond ||= action(:respond)
       @respond.call(env)
@@ -107,7 +112,7 @@ def i18n_message(default = nil)
         options[:default] = [message]
         auth_keys = scope_class.authentication_keys
         keys = (auth_keys.respond_to?(:keys) ? auth_keys.keys : auth_keys).map { |key| scope_class.human_attribute_name(key) }
-        options[:authentication_keys] = keys.join(I18n.translate(:"support.array.words_connector"))
+        options[:authentication_keys] = keys.join(I18n.t(:"support.array.words_connector"))
         options = i18n_options(options)
 
         I18n.t(:"#{scope}.#{message}", **options)
@@ -116,6 +121,10 @@ def i18n_message(default = nil)
       end
     end
 
+    def i18n_locale
+      warden_options[:locale]
+    end
+
     def redirect_url
       if warden_message == :timeout
         flash[:timedout] = true if is_flashing_format?

test/controllers/helpers_test.rb

@@ -64,30 +64,30 @@ def setup
   end
 
   test 'proxy authenticate_user! to authenticate with user scope' do
-    @mock_warden.expects(:authenticate!).with({ scope: :user })
+    @mock_warden.expects(:authenticate!).with({ scope: :user, locale: :en })
     @controller.authenticate_user!
   end
 
   test 'proxy authenticate_user! options to authenticate with user scope' do
-    @mock_warden.expects(:authenticate!).with({ scope: :user, recall: "foo" })
+    @mock_warden.expects(:authenticate!).with({ scope: :user, recall: "foo", locale: :en })
     @controller.authenticate_user!(recall: "foo")
   end
 
   test 'proxy authenticate_admin! to authenticate with admin scope' do
-    @mock_warden.expects(:authenticate!).with({ scope: :admin })
+    @mock_warden.expects(:authenticate!).with({ scope: :admin, locale: :en })
     @controller.authenticate_admin!
   end
 
   test 'proxy authenticate_[group]! to authenticate!? with each scope' do
     [:user, :admin].each do |scope|
-      @mock_warden.expects(:authenticate!).with({ scope: scope })
+      @mock_warden.expects(:authenticate!).with({ scope: scope, locale: :en })
       @mock_warden.expects(:authenticate?).with(scope: scope).returns(false)
     end
     @controller.authenticate_commenter!
   end
 
   test 'proxy authenticate_publisher_account! to authenticate with namespaced publisher account scope' do
-    @mock_warden.expects(:authenticate!).with({ scope: :publisher_account })
+    @mock_warden.expects(:authenticate!).with({ scope: :publisher_account, locale: :en })
     @controller.authenticate_publisher_account!
   end
 

test/failure_app_test.rb

@@ -200,6 +200,13 @@ def call_failure(env_params = {})
       assert_equal 'User Steve does not exist', @request.flash[:alert]
     end
 
+    test 'respects the i18n locale passed via warden options when redirecting' do
+      call_failure('warden' => OpenStruct.new(message: :invalid), 'warden.options' => { locale: :"pt-BR" })
+
+      assert_equal 'Email ou senha inválidos.', @request.flash[:alert]
+      assert_equal 'http://test.host/users/sign_in', @response.second["Location"]
+    end
+
     test 'uses the proxy failure message as string' do
       call_failure('warden' => OpenStruct.new(message: 'Hello world'))
       assert_equal 'Hello world', @request.flash[:alert]
@@ -284,6 +291,12 @@ def call_failure(env_params = {})
       assert_match '<error>Invalid Email or password.</error>', @response.third.body
     end
 
+    test 'respects the i18n locale passed via warden options when responding to HTTP request' do
+      call_failure('formats' => Mime[:json], 'warden' => OpenStruct.new(message: :invalid), 'warden.options' => { locale: :"pt-BR" })
+
+      assert_equal %({"error":"Email ou senha inválidos."}), @response.third.body
+    end
+
     context 'on ajax call' do
       context 'when http_authenticatable_on_xhr is false' do
         test 'dont return 401 with navigational formats' do
@@ -372,6 +385,18 @@ def call_failure(env_params = {})
       end
     end
 
+    test 'respects the i18n locale passed via warden options when recalling original controller' do
+      env = {
+        "warden.options" => { recall: "devise/sessions#new", attempted_path: "/users/sign_in", locale: :"pt-BR" },
+        "devise.mapping" => Devise.mappings[:user],
+        "warden" => stub_everything
+      }
+      call_failure(env)
+
+      assert_includes @response.third.body, '<h2>Log in</h2>'
+      assert_includes @response.third.body, 'Email ou senha inválidos.'
+    end
+
     # TODO: remove conditional/else when supporting only responders 3.1+
     if ActionController::Responder.respond_to?(:error_status=)
       test 'respects the configured responder `error_status` for the status code' do
@@ -431,6 +456,7 @@ def call_failure(env_params = {})
       assert_equal "yes it does", Devise::FailureApp.new.lazy_loading_works?
     end
   end
+
   context "Without Flash Support" do
     test "returns to the default redirect location without a flash message" do
       call_failure request_klass: RequestWithoutFlashSupport

test/integration/authenticatable_test.rb

@@ -273,6 +273,15 @@ class AuthenticationRedirectTest < Devise::IntegrationTest
     assert_contain 'You need to sign in or sign up before continuing.'
   end
 
+  test 'redirect from warden respects i18n locale set at the controller' do
+    get admins_path(locale: "pt-BR")
+
+    assert_redirected_to new_admin_session_path
+    follow_redirect!
+
+    assert_contain 'Para continuar, faça login ou registre-se.'
+  end
+
   test 'redirect to default url if no other was configured' do
     sign_in_as_user
     assert_template 'home/index'

test/rails_app/app/controllers/admins_controller.rb

@@ -1,8 +1,15 @@
 # frozen_string_literal: true
 
 class AdminsController < ApplicationController
+  around_action :set_locale
   before_action :authenticate_admin!
 
   def index
   end
+
+  private
+
+  def set_locale
+    I18n.with_locale(params[:locale] || I18n.default_locale) { yield }
+  end
 end

test/support/locale/pt-BR.yml

@@ -0,0 +1,5 @@
+pt-BR:
+  devise:
+    failure:
+      invalid: "%{authentication_keys} ou senha inválidos."
+      unauthenticated: "Para continuar, faça login ou registre-se."

test/test_helper.rb

@@ -10,7 +10,7 @@
 require "rails/test_help"
 require "orm/#{DEVISE_ORM}"
 
-I18n.load_path << File.expand_path("../support/locale/en.yml", __FILE__)
+I18n.load_path.concat Dir["#{File.dirname(__FILE__)}/support/locale/*.yml"]
 
 require 'mocha/minitest'
 require 'timecop'