Override default_render's behavior with a block

In 0de4a23 the behavior when there is a missing template was changed to
not raise an error, but instead head :no_content.  This is a breaking
change and some gems rely on this happening.

To allow gems and other code to work around this, allow
`default_render` to take a block which, if provided, will
execute the contents of that block instead of doing the `head :no_content`.

1 files changed, 21 insertions, 0 deletions

diff --git a/actionpack/test/controller/mime/respond_to_test.rb b/actionpack/test/controller/mime/respond_to_test.rb
index 7aef8a50ce..8591bdb4d9 100644
--- a/actionpack/test/controller/mime/respond_to_test.rb
+++ b/actionpack/test/controller/mime/respond_to_test.rb
@@ -793,3 +793,24 @@ class RespondToControllerTest < ActionController::TestCase
     assert_equal "phone", @response.body
   end
 end
+
+class RespondToWithBlockOnDefaultRenderController < ActionController::Base
+  def show
+    default_render do
+      render text: 'default_render yielded'
+    end
+  end
+end
+
+class RespondToWithBlockOnDefaultRenderControllerTest < ActionController::TestCase
+  def setup
+    super
+    @request.host = "www.example.com"
+  end
+
+  def test_default_render_uses_block_when_no_template_exists
+    get :show
+    assert_equal "default_render yielded", @response.body
+    assert_equal "text/html", @response.content_type
+  end
+end