Fix devise not rendering errors as flash messages

https://github.com/heartcombo/devise/issues/5446

closes #63

app/controllers/turbo_controller.rb

@@ -0,0 +1,18 @@
+class TurboController < ApplicationController
+  class Responder < ActionController::Responder
+    def to_turbo_stream
+      controller.render(options.merge(formats: :html))
+    rescue ActionView::MissingTemplate => error
+      if get?
+        raise error
+      elsif has_errors? && default_action
+        render rendering_options.merge(formats: :html, status: :unprocessable_entity)
+      else
+        redirect_to navigation_location
+      end
+    end
+  end
+
+  self.responder = Responder
+  respond_to :html, :turbo_stream
+end

app/controllers/users/devise_controller.rb

@@ -0,0 +1,18 @@
+class Users::DeviseController < ApplicationController
+  class Responder < ActionController::Responder
+    def to_turbo_stream
+      controller.render(options.merge(formats: :html))
+    rescue ActionView::MissingTemplate => error
+      if get?
+        raise error
+      elsif has_errors? && default_action
+        render rendering_options.merge(formats: :html, status: :unprocessable_entity)
+      else
+        redirect_to navigation_location
+      end
+    end
+  end
+
+  self.responder = Responder
+  respond_to :html, :turbo_stream
+end

app/views/devise/shared/_error_messages.html.erb

@@ -2,7 +2,7 @@
   <div id="error_explanation">
     <ul>
       <% resource.errors.full_messages.each do |message| %>
-        <li><%= message %></li>
+        <li class="text-red-600"><%= message %></li>
       <% end %>
     </ul>
   </div>

config/initializers/devise.rb

@@ -3,6 +3,21 @@ require 'digest'
 require 'securerandom'
 # frozen_string_literal: true
 
+# Create custom failure for turbo
+class TurboFailureApp < Devise::FailureApp
+  def respond
+    if request_format == :turbo_stream
+      redirect
+    else
+      super
+    end
+  end
+
+  def skip_format?
+    %w(html turbo_stream */*).include? request_format.to_s
+  end
+end
+
 # Assuming you have not yet modified this file, each configuration option below
 # is set to its default value. Note that some are commented out while others
 # are not: uncommented lines are intended to protect your configuration from
@@ -44,6 +59,7 @@ Devise.setup do |config|
   # ==> Controller configuration
   # Configure the parent class to the devise controllers.
   # config.parent_controller = 'DeviseController'
+  config.parent_controller = 'TurboController'
 
   # ==> Mailer Configuration
   # Configure the e-mail address which will be shown in Devise::Mailer,
@@ -289,6 +305,7 @@ Devise.setup do |config|
   #
   # The "*/*" below is required to match Internet Explorer requests.
   # config.navigational_formats = ['*/*', :html]
+  config.navigational_formats = ['*/*', :html, :turbo_stream]
 
   # The default HTTP method used to sign out a resource. Default is :delete.
   config.sign_out_via = :get
@@ -302,10 +319,11 @@ Devise.setup do |config|
   # If you want to use other strategies, that are not supported by Devise, or
   # change the failure app, you can configure them inside the config.warden block.
   #
-  # config.warden do |manager|
-  #   manager.intercept_401 = false
-  #   manager.default_strategies(scope: :user).unshift :some_external_strategy
-  # end
+  config.warden do |manager|
+    manager.failure_app = TurboFailureApp
+    # manager.intercept_401 = false
+    # manager.default_strategies(scope: :user).unshift :some_external_strategy
+  end
 
   # ==> Mountable engine configurations
   # When using Devise inside an engine, let's call it `MyEngine`, and this engine