Fixed #16935 - misleading message if AttributeError escapes during SimpleTemplateResponse.render

Thanks to isagalaev for the report.

As discussed on django-devs, this reverts some of the changes in [16568]
i.e.  the addition of `SimpleTemplateResponse.__getattr__`, because this
makes it much harder to debug the common case of an AttributeError somewhere
during the rendering of a SimpleTemplateResponse.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@16917 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/template/response.py

@@ -6,10 +6,6 @@ class ContentNotRenderedError(Exception):
     pass
 
 
-class DiscardedAttributeError(AttributeError):
-    pass
-
-
 class SimpleTemplateResponse(HttpResponse):
     rendering_attrs = ['template_name', 'context_data', '_post_render_callbacks']
 
@@ -36,7 +32,6 @@ class SimpleTemplateResponse(HttpResponse):
         # True, so we initialize it to False after the call to super __init__.
         self._is_rendered = False
 
-
     def __getstate__(self):
         """Pickling support function.
 
@@ -54,13 +49,6 @@ class SimpleTemplateResponse(HttpResponse):
 
         return obj_dict
 
-    def __getattr__(self, name):
-        if name in self.rendering_attrs:
-            raise DiscardedAttributeError('The %s attribute was discarded '
-                                          'when this %s class was pickled.' %
-                                          (name, self.__class__.__name__))
-        return super(SimpleTemplateResponse, self).__getattr__(name)
-
     def resolve_template(self, template):
         "Accepts a template object, path-to-template or list of paths"
         if isinstance(template, (list, tuple)):

tests/regressiontests/templates/response.py

@@ -9,8 +9,7 @@ from django.conf import settings
 import django.template.context
 from django.template import Template, Context
 from django.template.response import (TemplateResponse, SimpleTemplateResponse,
-                                      ContentNotRenderedError,
-                                      DiscardedAttributeError)
+                                      ContentNotRenderedError)
 
 def test_processor(request):
     return {'processors': 'yes'}
@@ -198,7 +197,7 @@ class SimpleTemplateResponseTest(BaseTemplateResponseTest):
 
         # ...and requesting any of those attributes raises an exception
         for attr in template_attrs:
-            with self.assertRaises(DiscardedAttributeError) as cm:
+            with self.assertRaises(AttributeError):
                 getattr(unpickled_response, attr)
 
     def test_repickling(self):
@@ -282,7 +281,7 @@ class TemplateResponseTest(BaseTemplateResponseTest):
 
         # ...and requesting any of those attributes raises an exception
         for attr in template_attrs:
-            with self.assertRaises(DiscardedAttributeError) as cm:
+            with self.assertRaises(AttributeError):
                 getattr(unpickled_response, attr)
 
     def test_repickling(self):