clone a new RendererHelper per request

CHANGES.txt

@@ -169,6 +169,13 @@ Bug Fixes
 - Prevent "parameters to load are deprecated" ``DeprecationWarning``
   from setuptools>=11.3. See https://github.com/Pylons/pyramid/pull/1541
 
+- Avoiding sharing the ``IRenderer`` objects across threads when attached to
+  a view using the `renderer=` argument. These renderers were instantiated
+  at time of first render and shared between requests, causing potentially
+  subtle effects like `pyramid.reload_templates = true` failing to work
+  in `pyramid_mako`. See https://github.com/Pylons/pyramid/pull/1575
+  and https://github.com/Pylons/pyramid/issues/1268
+
 - Avoiding timing attacks against CSRF tokens.
   See https://github.com/Pylons/pyramid/pull/1574
 

pyramid/config/views.py

@@ -349,7 +349,6 @@ def rendered_view(self, view):
 
     def _rendered_view(self, view, view_renderer):
         def rendered_view(context, request):
-            renderer = view_renderer
             result = view(context, request)
             if result.__class__ is Response: # potential common case
                 response = result
@@ -367,6 +366,8 @@ def rendered_view(context, request):
                             name=renderer_name,
                             package=self.kw.get('package'),
                             registry = registry)
+                    else:
+                        renderer = view_renderer.clone()
                     if '__view__' in attrs:
                         view_inst = attrs.pop('__view__')
                     else:

pyramid/interfaces.py

@@ -382,6 +382,9 @@ class IRendererInfo(Interface):
     settings = Attribute('The deployment settings dictionary related '
                          'to the current application')
 
+    def clone():
+        """ Return a shallow copy that does not share any mutable state."""
+
 class IRendererFactory(Interface):
     def __call__(info):
         """ Return an object that implements

pyramid/tests/test_config/test_views.py

@@ -2548,6 +2548,8 @@ def render_view(inself, req, resp, view_inst, ctx):
                 self.assertEqual(view_inst, view)
                 self.assertEqual(ctx, context)
                 return response
+            def clone(self):
+                return self
         def view(request):
             return 'OK'
         deriver = self._makeOne(renderer=moo())
@@ -2585,6 +2587,8 @@ def render_view(inself, req, resp, view_inst, ctx):
                 self.assertEqual(view_inst, 'view')
                 self.assertEqual(ctx, context)
                 return response
+            def clone(self):
+                return self
         def view(request):
             return 'OK'
         deriver = self._makeOne(renderer=moo())
@@ -3179,6 +3183,8 @@ def render_view(inself, req, resp, view_inst, ctx):
                 self.assertEqual(view_inst.__class__, View)
                 self.assertEqual(ctx, context)
                 return response
+            def clone(self):
+                return self
         class View(object):
             def __init__(self, context, request):
                 pass
@@ -3203,6 +3209,8 @@ def render_view(inself, req, resp, view_inst, ctx):
                 self.assertEqual(view_inst.__class__, View)
                 self.assertEqual(ctx, context)
                 return response
+            def clone(self):
+                return self
         class View(object):
             def __init__(self, request):
                 pass
@@ -3227,6 +3235,8 @@ def render_view(inself, req, resp, view_inst, ctx):
                 self.assertEqual(view_inst.__class__, View)
                 self.assertEqual(ctx, context)
                 return response
+            def clone(self):
+                return self
         class View:
             def __init__(self, context, request):
                 pass
@@ -3251,6 +3261,8 @@ def render_view(inself, req, resp, view_inst, ctx):
                 self.assertEqual(view_inst.__class__, View)
                 self.assertEqual(ctx, context)
                 return response
+            def clone(self):
+                return self
         class View:
             def __init__(self, request):
                 pass
@@ -3275,6 +3287,8 @@ def render_view(inself, req, resp, view_inst, ctx):
                 self.assertEqual(view_inst, view)
                 self.assertEqual(ctx, context)
                 return response
+            def clone(self):
+                return self
         class View:
             def index(self, context, request):
                 return {'a':'1'}
@@ -3297,6 +3311,8 @@ def render_view(inself, req, resp, view_inst, ctx):
                 self.assertEqual(view_inst, view)
                 self.assertEqual(ctx, context)
                 return response
+            def clone(self):
+                return self
         class View:
             def index(self, request):
                 return {'a':'1'}