Some more AV work:

  * rename _render_partial to _render_partial_unknown_type to reflect that for this call, 
  	we don't know the type.
  * Merge _render_partial_with_block and _render_partial_with_layout to _render_partial
    * TODO: Check to see if any more logic can be shared
    * TODO: See about streamlining block path so we can get rid of @_proc_for_layout
  * Remove @exempt_from_layout as it is no longer needed

actionpack/lib/action_view/render/partials.rb

@@ -185,10 +185,10 @@ def _partial_names
 
     def render_partial(options)
       @assigns_added = false
-      _render_partial(options)
+      _render_partial_unknown_type(options)
     end
 
-    def _render_partial(options) #:nodoc:
+    def _render_partial_unknown_type(options) #:nodoc:
       options[:locals] ||= {}
 
       path = partial = options[:partial]
@@ -220,19 +220,21 @@ def _partial_path(object)
         end
       end
 
-      def _render_partial_with_block(layout, block, options)
-        @_proc_for_layout = block
-        concat(_render_partial(options.merge(:partial => layout)))
-      ensure
-        @_proc_for_layout = nil
-      end
-
-      def _render_partial_with_layout(layout, options)
-        if layout
-          prefix = layout.include?(?/) ? nil : controller_path
-          layout = find_by_parts(layout, {:formats => formats}, prefix, true)
+      def _render_partial(layout, options, block = nil)
+        if block
+          begin
+            @_proc_for_layout = block
+            concat(_render_partial_unknown_type(options.merge(:partial => layout)))
+          ensure
+            @_proc_for_layout = nil
+          end
+        else
+          if layout
+            prefix = layout.include?(?/) ? nil : controller_path
+            layout = find_by_parts(layout, {:formats => formats}, prefix, true)
+          end
+          _render_content(_render_partial_unknown_type(options), layout, options[:locals])
         end
-        _render_content(_render_partial(options), layout, options[:locals])
       end
 
       def _render_partial_object(template, options)
@@ -260,7 +262,8 @@ def _set_locals(object, locals, template, options)
       def _render_partial_collection(collection, options = {}, passed_template = nil) #:nodoc:
         return nil if collection.blank?
 
-        spacer = options[:spacer_template] ? _render_partial(:partial => options[:spacer_template]) : ''
+        spacer = options[:spacer_template] ?
+          _render_partial_unknown_type(:partial => options[:spacer_template]) : ''
 
         locals = (options[:locals] ||= {})
         index, @_partial_path = 0, nil

actionpack/lib/action_view/render/rendering.rb

@@ -10,33 +10,29 @@ module Rendering
     #
     # If no options hash is passed or :update specified, the default is to render a partial and use the second parameter
     # as the locals hash.
-    def render(options = {}, local_assigns = {}, &block) #:nodoc:
-      local_assigns ||= {}
-
-      @exempt_from_layout = true
-
+    def render(options = {}, locals = {}, &block) #:nodoc:
       case options
+      when String, NilClass
+        _render_partial_unknown_type(:partial => options, :locals => locals || {})
       when Hash
-        options[:locals] ||= {}
         layout = options[:layout]
 
-        return _render_partial_with_layout(layout, options) if options.key?(:partial)
-        return _render_partial_with_block(layout, block, options) if block_given?
+        if options.key?(:partial) || block_given?
+          return _render_partial(layout, options, block)
+        end
 
         layout = find_by_parts(layout, {:formats => formats}) if layout
 
         if file = options[:file]
           template = find_by_parts(file, {:formats => formats})
-          _render_template(template, layout, :locals => options[:locals])
+          _render_template(template, layout, :locals => options[:locals] || {})
         elsif inline = options[:inline]
           _render_inline(inline, layout, options)
         elsif text = options[:text]
           _render_text(text, layout, options)
         end
       when :update
         update_page(&block)
-      when String, NilClass
-        _render_partial(:partial => options, :locals => local_assigns)
       end
     end