1 files changed, 17 insertions, 1 deletions
diff --git a/actionview/lib/action_view/lookup_context.rb b/actionview/lib/action_view/lookup_context.rb
index f9d5b97fe3..855fed0190 100644
--- a/actionview/lib/action_view/lookup_context.rb
+++ b/actionview/lib/action_view/lookup_context.rb
@@ -1,6 +1,7 @@
 require 'thread_safe'
 require 'active_support/core_ext/module/remove_method'
 require 'active_support/core_ext/module/attribute_accessors'
+require 'action_view/template/resolver'
 
 module ActionView
   # = Action View Lookup Context
@@ -52,6 +53,7 @@ module ActionView
       locales
     end
     register_detail(:formats) { ActionView::Base.default_formats || [:html, :text, :js, :css,  :xml, :json] }
+    register_detail(:variants) { [] }
     register_detail(:handlers){ Template::Handlers.extensions }
 
     class DetailsKey #:nodoc:
@@ -62,6 +64,13 @@ module ActionView
       @details_keys = ThreadSafe::Cache.new
 
       def self.get(details)
+        if details[:formats]
+          details = details.dup
+          syms    = Set.new Mime::SET.symbols
+          details[:formats] = details[:formats].select { |v|
+            syms.include? v
+          }
+        end
         @details_keys[details] ||= new
       end
 
@@ -150,7 +159,14 @@ module ActionView
       def detail_args_for(options)
         return @details, details_key if options.empty? # most common path.
         user_details = @details.merge(options)
-        [user_details, DetailsKey.get(user_details)]
+
+        if @cache
+          details_key = DetailsKey.get(user_details)
+        else
+          details_key = nil
+        end
+
+        [user_details, details_key]
       end
 
       # Support legacy foo.erb names even though we now ignore .erb