Abstract the no-longer-using-Haml functionality into Haml::Helpers#non_haml.

lib/haml/helpers.rb

@@ -41,6 +41,24 @@ module Haml
       nil
     end
 
+    # call-seq:
+    #   non_haml { ... }
+    #
+    # Runs a block of code in a non-Haml context
+    # (i.e. #is_haml? will return false).
+    #
+    # This is mainly useful for rendering sub-templates such as partials in a non-Haml language,
+    # particularly where helpers may behave differently when run from Haml.
+    #
+    # Note that this is automatically applied to Rails partials.
+    def non_haml
+      old_buffer = @haml_buffer
+      @haml_buffer = nil
+      res = yield
+      @haml_buffer = old_buffer
+      res
+    end
+
     # call-seq:
     #   find_and_preserve(input)
     #   find_and_preserve {...}

lib/haml/helpers/action_view_mods.rb

@@ -2,11 +2,8 @@ if defined?(ActionView) and not defined?(Merb::Plugins)
   module ActionView
     class Base # :nodoc:
       def render_with_haml(*args, &block)
-        old_buffer = @haml_buffer
-        @haml_buffer = nil
-        res = render_without_haml(*args, &block)
-        @haml_buffer = old_buffer
-        res
+        return non_haml { render_without_haml(*args, &block) } if is_haml?
+        render_without_haml(*args, &block)
       end
       alias_method :render_without_haml, :render
       alias_method :render, :render_with_haml

test/haml/helper_test.rb

@@ -165,5 +165,9 @@ class HelperTest < Test::Unit::TestCase
 
     assert_equal("<p attr='val'>\n  Blah\n</p>\n", result)
   end
+
+  def test_non_haml
+    assert_equal("false\n", render("= non_haml { is_haml? }"))
+  end
 end