it is now possible to pass details options (:formats, :details, :locales, ...) to #render, #find_template and friends. this doesn't change anything in global context.

actionpack/lib/action_view/lookup_context.rb

@@ -125,17 +125,17 @@ module ActionView
         @view_paths = ActionView::PathSet.new(Array.wrap(paths))
       end
 
-      def find(name, prefixes = [], partial = false, keys = [])
-        @view_paths.find(*args_for_lookup(name, prefixes, partial, keys))
+      def find(name, prefixes = [], partial = false, keys = [], options = {})
+        @view_paths.find(*args_for_lookup(name, prefixes, partial, keys, options))
       end
       alias :find_template :find
 
-      def find_all(name, prefixes = [], partial = false, keys = [])
-        @view_paths.find_all(*args_for_lookup(name, prefixes, partial, keys))
+      def find_all(name, prefixes = [], partial = false, keys = [], options = {})
+        @view_paths.find_all(*args_for_lookup(name, prefixes, partial, keys, options))
       end
 
-      def exists?(name, prefixes = [], partial = false, keys = [])
-        @view_paths.exists?(*args_for_lookup(name, prefixes, partial, keys))
+      def exists?(name, prefixes = [], partial = false, keys = [], options = {})
+        @view_paths.exists?(*args_for_lookup(name, prefixes, partial, keys, options))
       end
       alias :template_exists? :exists?
 
@@ -154,9 +154,17 @@ module ActionView
 
     protected
 
-      def args_for_lookup(name, prefixes, partial, keys) #:nodoc:
+      def args_for_lookup(name, prefixes, partial, keys, details_options) #:nodoc:
         name, prefixes = normalize_name(name, prefixes)
-        [name, prefixes, partial || false, @details, details_key, keys]
+        details, details_key = detail_args_for(details_options)
+        [name, prefixes, partial || false, details, details_key, keys]
+      end
+
+      # Compute details hash and key according to user options (e.g. passed from #render).
+      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)]
       end
 
       # Support legacy foo.erb names even though we now ignore .erb

actionpack/lib/action_view/renderer/template_renderer.rb

@@ -16,11 +16,12 @@ module ActionView
     # Determine the template to be rendered using the given options.
     def determine_template(options) #:nodoc:
       keys    = options[:locals].try(:keys) || []
+      details = options.slice(:formats, :locale, :handlers)
 
       if options.key?(:text)
         Template::Text.new(options[:text], formats.try(:first))
       elsif options.key?(:file)
-        with_fallbacks { find_template(options[:file], nil, false, keys) }
+        with_fallbacks { find_template(options[:file], nil, false, keys, details) }
       elsif options.key?(:inline)
         handler = Template.handler_for_extension(options[:type] || "erb")
         Template.new(options[:inline], "inline template", handler, :locals => keys)

actionpack/test/fixtures/comments/empty.html.erb

@@ -0,0 +1 @@
+<h1>No Comment</h1>

actionpack/test/fixtures/comments/empty.xml.erb

@@ -0,0 +1 @@
+<error>No Comment</error>

actionpack/test/template/render_test.rb

@@ -32,6 +32,12 @@ module RenderTestCases
     assert_equal "Hello world!", @view.render(:file => "test/hello_world")
   end
 
+  # Test if :formats, :locale etc. options are passed correctly to the resolvers.
+  def test_render_file_with_format
+    assert_equal "<h1>No Comment</h1>", @view.render(:file => "comments/empty", :formats => [:html])
+    assert_equal "<error>No Comment</error>", @view.render(:file => "comments/empty", :formats => [:xml])
+  end
+
   def test_render_file_with_localization
     old_locale, @view.locale = @view.locale, :da
     assert_equal "Hey verden", @view.render(:file => "test/hello_world")