Make generated test work even when using virtual attributes

The virtual attributes(`attachment` and `rich_text`) can't set value
with `fill_in`. So avoid using it. Once #35885 is merged, will be
modified to use it.

Also, add checking attachment attached or not for avoiding
`DelegationError` when attachment didn't attach.

railties/lib/rails/generators/erb/scaffold/templates/show.html.erb.tt

@@ -4,7 +4,7 @@
 <p>
   <strong><%= attribute.human_name %>:</strong>
 <% if attribute.attachment? -%>
-  <%%= link_to @<%= singular_table_name %>.<%= attribute.column_name %>.filename, @<%= singular_table_name %>.<%= attribute.column_name %> %>
+  <%%= link_to @<%= singular_table_name %>.<%= attribute.column_name %>.filename, @<%= singular_table_name %>.<%= attribute.column_name %> if @<%= singular_table_name %>.<%= attribute.column_name %>.attached? %>
 <% elsif attribute.attachments? -%>
   <%% @<%= singular_table_name %>.<%= attribute.column_name %>.each do |<%= attribute.singular_name %>| %>
     <div><%%= link_to <%= attribute.singular_name %>.filename, <%= attribute.singular_name %> %></div>

railties/lib/rails/generators/named_base.rb

@@ -187,7 +187,6 @@ module Rails
 
         def attributes_names # :doc:
           @attributes_names ||= attributes.each_with_object([]) do |a, names|
-            next if a.attachments?
             names << a.column_name
             names << "password_confirmation" if a.password_digest?
             names << "#{a.name}_type" if a.polymorphic?

railties/lib/rails/generators/rails/scaffold_controller/scaffold_controller_generator.rb

@@ -36,9 +36,15 @@ module Rails
       private
 
         def permitted_params
-          params = attributes_names.map { |name| ":#{name}" }.join(", ")
-          params += attributes.select(&:attachments?).map { |a| ", #{a.name}: []" }.join
-          params
+          attachments, others = attributes_names.partition { |name| attachments?(name) }
+          params = others.map { |name| ":#{name}" }
+          params += attachments.map { |name| "#{name}: []" }
+          params.join(", ")
+        end
+
+        def attachments?(name)
+          attribute = attributes.find { |attr| attr.name == name }
+          attribute&.attachments?
         end
     end
   end

railties/lib/rails/generators/test_unit/scaffold/scaffold_generator.rb

@@ -49,16 +49,21 @@ module TestUnit # :nodoc:
           attributes_names.map do |name|
             if %w(password password_confirmation).include?(name) && attributes.any?(&:password_digest?)
               ["#{name}", "'secret'"]
-            else
+            elsif !virtual?(name)
               ["#{name}", "@#{singular_table_name}.#{name}"]
             end
-          end.sort.to_h
+          end.compact.sort.to_h
         end
 
         def boolean?(name)
           attribute = attributes.find { |attr| attr.name == name }
           attribute&.type == :boolean
         end
+
+        def virtual?(name)
+          attribute = attributes.find { |attr| attr.name == name }
+          attribute&.virtual?
+        end
     end
   end
 end

railties/test/generators/scaffold_controller_generator_test.rb

@@ -89,6 +89,15 @@ class ScaffoldControllerGeneratorTest < Rails::Generators::TestCase
     end
   end
 
+  def test_controller_permit_attachments_attributes_only
+    run_generator ["Message", "photos:attachments"]
+
+    assert_file "app/controllers/messages_controller.rb" do |content|
+      assert_match(/def message_params/, content)
+      assert_match(/params\.require\(:message\)\.permit\(photos: \[\]\)/, content)
+    end
+  end
+
   def test_helper_are_invoked_with_a_pluralized_name
     run_generator
     assert_file "app/helpers/users_helper.rb", /module UsersHelper/

railties/test/generators/scaffold_generator_test.rb

@@ -487,6 +487,36 @@ class ScaffoldGeneratorTest < Rails::Generators::TestCase
       assert_match(/^\W{4}<%= form\.file_field :video %>/, content)
       assert_match(/^\W{4}<%= form\.file_field :photos, multiple: true %>/, content)
     end
+
+    assert_file "app/views/messages/show.html.erb" do |content|
+      assert_match(/^\W{2}<%= link_to @message\.video\.filename, @message\.video if @message\.video\.attached\? %>/, content)
+      assert_match(/^\W{4}<div><%= link_to photo\.filename, photo %>/, content)
+    end
+
+    assert_file "test/system/messages_test.rb" do |content|
+      assert_no_match(/fill_in "Video"/, content)
+      assert_no_match(/fill_in "Photos"/, content)
+    end
+  end
+
+  def test_scaffold_generator_rich_text
+    run_generator ["message", "content:rich_text"]
+
+    assert_file "app/models/message.rb", /rich_text :content/
+
+    assert_file "app/controllers/messages_controller.rb" do |content|
+      assert_instance_method :message_params, content do |m|
+        assert_match(/permit\(:content\)/, m)
+      end
+    end
+
+    assert_file "app/views/messages/_form.html.erb" do |content|
+      assert_match(/^\W{4}<%= form\.rich_text_area :content %>/, content)
+    end
+
+    assert_file "test/system/messages_test.rb" do |content|
+      assert_no_match(/fill_in "Content"/, content)
+    end
   end
 
   def test_scaffold_generator_database