- In the past if a renderer returned ``None``, the body of the resulting

  response would be set explicitly to the empty string.  Instead, now, the body
  is left unchanged, which allows the renderer to set a body itself by using
  e.g. ``request.response.body = b'foo'``.  The body set by the renderer will
  be unmolested on the way out.  See
  https://github.com/Pylons/pyramid/issues/709

Closes #709

3 files changed, 26 insertions, 8 deletions

diff --git a/CHANGES.txt b/CHANGES.txt
index 563851e74..0ef1a0593 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -21,6 +21,16 @@ Features
   it doesn't make sense to assert that a nonexistent view is
   execution-permitted. See https://github.com/Pylons/pyramid/issues/299.
 
+Bug Fixes
+---------
+
+- In the past if a renderer returned ``None``, the body of the resulting
+  response would be set explicitly to the empty string.  Instead, now, the body
+  is left unchanged, which allows the renderer to set a body itself by using
+  e.g. ``request.response.body = b'foo'``.  The body set by the renderer will
+  be unmolested on the way out.  See
+  https://github.com/Pylons/pyramid/issues/709
+
 1.4a3 (2012-10-26)
 ==================
 
diff --git a/pyramid/renderers.py b/pyramid/renderers.py
index 57a61ebba..6839d72f5 100644
--- a/pyramid/renderers.py
+++ b/pyramid/renderers.py
@@ -573,13 +573,11 @@ class RendererHelper(object):
 
             response = response_factory()
 
-        if result is None:
-            result = ''
-
-        if isinstance(result, text_type):
-            response.text = result
-        else:
-            response.body = result
+        if result is not None:
+            if isinstance(result, text_type):
+                response.text = result
+            else:
+                response.body = result
 
         if request is not None:
             # deprecated mechanism to set up request.response_* attrs, see
diff --git a/pyramid/tests/test_renderers.py b/pyramid/tests/test_renderers.py
index cb6c364a7..befb714bd 100644
--- a/pyramid/tests/test_renderers.py
+++ b/pyramid/tests/test_renderers.py
@@ -663,13 +663,23 @@ class TestRendererHelper(unittest.TestCase):
         response = helper._make_response(la.encode('utf-8'), request)
         self.assertEqual(response.body, la.encode('utf-8'))
 
-    def test__make_response_result_is_None(self):
+    def test__make_response_result_is_None_no_body(self):
         from pyramid.response import Response
         request = testing.DummyRequest()
         request.response = Response()
         helper = self._makeOne('loo.foo')
         response = helper._make_response(None, request)
         self.assertEqual(response.body, b'')
+
+    def test__make_response_result_is_None_existing_body_not_molested(self):
+        from pyramid.response import Response
+        request = testing.DummyRequest()
+        response = Response()
+        response.body = b'abc'
+        request.response = response
+        helper = self._makeOne('loo.foo')
+        response = helper._make_response(None, request)
+        self.assertEqual(response.body, b'abc')
         
     def test__make_response_with_content_type(self):
         from pyramid.response import Response