render :template => 'foo/bar.json' now works as it should.

actionpack/lib/abstract_controller/rendering.rb

@@ -12,7 +12,6 @@ def initialize(message = nil)
 
   # This is a class to fix I18n global state. Whenever you provide I18n.locale during a request,
   # it will trigger the lookup_context and consequently expire the cache.
-  # TODO Add some deprecation warnings to remove I18n.locale from controllers
   class I18nProxy < ::I18n::Config #:nodoc:
     attr_reader :i18n_config, :lookup_context
 

actionpack/lib/action_view/render/partials.rb

@@ -371,13 +371,15 @@ def partial_path(object = @object)
     end
 
     def _render_partial(options, &block) #:nodoc:
-      if defined?(@renderer)
-        @renderer.setup(options, block)
-      else
-        @renderer = PartialRenderer.new(self, options, block)
-      end
+      _wrap_formats(options[:partial]) do
+        if defined?(@renderer)
+          @renderer.setup(options, block)
+        else
+          @renderer = PartialRenderer.new(self, options, block)
+        end
 
-      @renderer.render
+        @renderer.render
+      end
     end
 
   end

actionpack/lib/action_view/render/rendering.rb

@@ -21,9 +21,11 @@ def render(options = {}, locals = {}, &block)
         elsif options.key?(:partial)
           _render_partial(options)
         else
-          template = _determine_template(options)
-          lookup_context.freeze_formats(template.formats, true)
-          _render_template(template, options[:layout], options)
+          _wrap_formats(options[:template] || options[:file]) do
+            template = _determine_template(options)
+            lookup_context.freeze_formats(template.formats, true)
+            _render_template(template, options[:layout], options)
+          end
         end
       when :update
         update_page(&block)
@@ -32,6 +34,19 @@ def render(options = {}, locals = {}, &block)
       end
     end
 
+    # Checks if the given path contains a format and if so, change
+    # the lookup context to take this new format into account.
+    def _wrap_formats(value)
+      return yield unless value.is_a?(String)
+      @@formats_regexp ||= /\.(#{Mime::SET.symbols.join('|')})$/
+
+      if value.sub!(@@formats_regexp, "")
+        update_details(:formats => [$1.to_sym]){ yield }
+      else
+        yield
+      end
+    end
+
     # Determine the template to be rendered using the given options.
     def _determine_template(options) #:nodoc:
       keys = (options[:locals] ||= {}).keys

actionpack/lib/action_view/template.rb

@@ -121,7 +121,7 @@ def initialize(source, identifier, handler, details)
       @method_names       = {}
       @locals             = details[:locals] || []
       @formats            = Array.wrap(details[:format] || :html).map(&:to_sym)
-      @virtual_path       = details[:virtual_path].try(:sub, ".#{@formats.first}", "")
+      @virtual_path       = details[:virtual_path]
       @compiled           = false
     end
 
@@ -286,7 +286,7 @@ def refresh(view)
         pieces  = @virtual_path.split("/")
         name    = pieces.pop
         partial = name.sub!(/^_/, "")
-        view.find_template(name, pieces.join, partial || false, @locals)
+        view.find_template(name, pieces.join, partial || false, ["unlikely_local_key"])
       end
 
       def method_name

actionpack/test/controller/new_base/render_partial_test.rb

@@ -5,10 +5,17 @@ module RenderPartial
   class BasicController < ActionController::Base
 
     self.view_paths = [ActionView::FixtureResolver.new(
-      "render_partial/basic/_basic.html.erb"    => "BasicPartial!",
-      "render_partial/basic/basic.html.erb"      => "<%= @test_unchanged = 'goodbye' %><%= render :partial => 'basic' %><%= @test_unchanged %>"
+      "render_partial/basic/_basic.html.erb"     => "BasicPartial!",
+      "render_partial/basic/basic.html.erb"      => "<%= @test_unchanged = 'goodbye' %><%= render :partial => 'basic' %><%= @test_unchanged %>",
+      "render_partial/basic/with_json.html.erb"  => "<%= render 'with_json.json' %>",
+      "render_partial/basic/_with_json.json.erb" => "<%= render 'final' %>",
+      "render_partial/basic/_final.json.erb"     => "{ final: json }"
     )]
 
+    def html_with_json_inside_json
+      render :action => "with_json"
+    end
+
     def changing
       @test_unchanged = 'hello'
       render :action => "basic"
@@ -22,6 +29,12 @@ class TestPartial < Rack::TestCase
       get :changing
       assert_response("goodbyeBasicPartial!goodbye")
     end
+
+    test "rendering a template with renders another partial with other format that renders other partial in the same format" do
+      get :html_with_json_inside_json
+      assert_content_type "text/html; charset=utf-8"
+      assert_response "{ final: json }"
+    end
   end
 
 end

actionpack/test/controller/new_base/render_template_test.rb

@@ -8,13 +8,20 @@ class WithoutLayoutController < ActionController::Base
       "shared.html.erb"          => "Elastica",
       "locals.html.erb"          => "The secret is <%= secret %>",
       "xml_template.xml.builder" => "xml.html do\n  xml.p 'Hello'\nend",
-      "with_raw.html.erb"        => "Hello <%=raw '<strong>this is raw</strong>' %>"
+      "with_raw.html.erb"        => "Hello <%=raw '<strong>this is raw</strong>' %>",
+      "test/with_json.html.erb"  => "<%= render :template => 'test/with_json.json' %>",
+      "test/with_json.json.erb"  => "<%= render :template => 'test/final' %>",
+      "test/final.json.erb"      => "{ final: json }"
     )]
 
     def index
       render :template => "test/basic"
     end
 
+    def html_with_json_inside_json
+      render :template => "test/with_json"
+    end
+
     def index_without_key
       render "test/basic"
     end
@@ -88,6 +95,12 @@ class TestWithoutLayout < Rack::TestCase
       assert_body "Hello <strong>this is raw</strong>"
       assert_status 200
     end
+
+    test "rendering a template with renders another template with other format that renders other template in the same format" do
+      get :html_with_json_inside_json
+      assert_content_type "text/html; charset=utf-8"
+      assert_response "{ final: json }"
+    end
   end
 
   class WithLayoutController < ::ApplicationController