From fcb04f53023d04b4b308acedb762bcefcf86f9a7 Mon Sep 17 00:00:00 2001
From: Leonardo Tegon <ltegon93@gmail.com>
Date: Mon, 11 Feb 2019 11:00:56 -0200
Subject: [PATCH] Check if `root_path` is defined with `#respond_to?` instead
 of `#present` (#5022)

When an application does not define a `root`, the method will be
undefined instead of returning a falsey value.
This commit also includes a new test with fake objects that mimic this
behavior.

Related resources:

* https://github.com/plataformatec/devise/commit/1aab4499330c8a7641a3dea7e2ec3b96acdf46ae#diff-c1be825bdb5f3160081e41432f83d0d7R278
* https://github.com/plataformatec/devise/issues/5021
---
 lib/devise/failure_app.rb |  2 +-
 test/failure_app_test.rb  | 28 ++++++++++++++++++++++++++++
 2 files changed, 29 insertions(+), 1 deletion(-)

diff --git a/lib/devise/failure_app.rb b/lib/devise/failure_app.rb
index 4894ecb779..9dcaea8d8c 100644
--- a/lib/devise/failure_app.rb
+++ b/lib/devise/failure_app.rb
@@ -275,7 +275,7 @@ def relative_url_root?
     private
 
     def root_path_defined?(context)
-      defined?(context.routes) && context.routes.url_helpers.root_path.present?
+      defined?(context.routes) && context.routes.url_helpers.respond_to?(:root_path)
     end
 
     def rails_5_and_down?
diff --git a/test/failure_app_test.rb b/test/failure_app_test.rb
index 2429d40673..af622fff26 100644
--- a/test/failure_app_test.rb
+++ b/test/failure_app_test.rb
@@ -28,6 +28,27 @@ def i18n_options(options)
     end
   end
 
+  class FailureWithoutRootPath < Devise::FailureApp
+    class FakeURLHelpers
+    end
+
+    class FakeRoutesWithoutRoot
+      def url_helpers
+        FakeURLHelpers.new
+      end
+    end
+
+    class FakeAppWithoutRootPath
+      def routes
+        FakeRoutesWithoutRoot.new
+      end
+    end
+
+    def main_app
+      FakeAppWithoutRootPath.new
+    end
+  end
+
   class FakeEngineApp < Devise::FailureApp
     class FakeEngine
       def new_user_on_engine_session_url _
@@ -103,6 +124,13 @@ def call_failure(env_params={})
       end
     end
 
+    test 'returns to the root path even when it\'s not defined' do
+      call_failure app: FailureWithoutRootPath
+      assert_equal 302, @response.first
+      assert_equal 'You need to sign in or sign up before continuing.', @request.flash[:alert]
+      assert_equal 'http://test.host/', @response.second['Location']
+    end
+
     test 'returns to the root path considering subdomain if no session path is available' do
       swap Devise, router_name: :fake_app do
         call_failure app: FailureWithSubdomain