Always return an array from formats so there is no need to wrap it when calling

railties/lib/rails/generators/erb.rb

@@ -6,7 +6,7 @@ class Base < Rails::Generators::NamedBase #:nodoc:
       protected
 
       def formats
-        format
+        [format]
       end
 
       def format

railties/lib/rails/generators/erb/controller/controller_generator.rb

@@ -11,7 +11,7 @@ def copy_view_files
 
         actions.each do |action|
           @action = action
-          Array(formats).each do |format|
+          formats.each do |format|
             @path = File.join(base_path, filename_with_extensions(action, format))
             template filename_with_extensions(:view, format), @path
           end

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

@@ -14,7 +14,7 @@ def create_root_folder
 
       def copy_view_files
         available_views.each do |view|
-          Array(formats).each do |format|
+          formats.each do |format|
             filename = filename_with_extensions(view, format)
             template filename, File.join("app/views", controller_file_path, filename)
           end