- Add undocumented ``__discriminator__`` API to derived view callables.

  e.g. ``adapters.lookup(...).__discriminator__(context, request)``.  It will
  be used by superdynamic systems that require the discriminator to be used
  for introspection after manual view lookup.

3 files changed, 54 insertions, 0 deletions

diff --git a/CHANGES.txt b/CHANGES.txt
index 8df5ab934..b5c1859c9 100644
--- a/CHANGES.txt
+++ b/CHANGES.txt
@@ -8,6 +8,11 @@ Features
   documented in the "Command-Line Pyramid" chapter in the section entitled
   "Invoking a Request".
 
+- Add undocumented ``__discriminator__`` API to derived view callables.
+  e.g. ``adapters.lookup(...).__discriminator__(context, request)``.  It will
+  be used by superdynamic systems that require the discriminator to be used
+  for introspection after manual view lookup.
+
 Bug Fixes
 ---------
 
diff --git a/pyramid/config/views.py b/pyramid/config/views.py
index 5efe1f2bb..3cca1c7c5 100644
--- a/pyramid/config/views.py
+++ b/pyramid/config/views.py
@@ -492,6 +492,15 @@ class MultiView(object):
         self.views = []
         self.accepts = []
 
+    def __discriminator__(self, context, request):
+        # used by introspection systems like so:
+        # view = adapters.lookup(....)
+        # view.__discriminator__(context, request) -> view's discriminator
+        # so that superdynamic systems can feed the discriminator to
+        # the introspection system to get info about it
+        view = self.match(context, request)
+        return view.__discriminator__(context, request)
+
     def add(self, view, order, accept=None, phash=None):
         if phash is not None:
             for i, (s, v, h) in enumerate(list(self.views)):
@@ -1034,6 +1043,10 @@ class ViewsConfiguratorMixin(object):
                                   decorator=decorator,
                                   http_cache=http_cache)
             derived_view = deriver(view)
+            derived_view.__discriminator__ = lambda *arg: discriminator
+            # __discriminator__ is used by superdynamic systems
+            # that require it for introspection after manual view lookup;
+            # see also MultiView.__discriminator__
             view_intr['derived_callable'] = derived_view
 
             registered = self.registry.adapters.registered
diff --git a/pyramid/tests/test_config/test_views.py b/pyramid/tests/test_config/test_views.py
index 30a30a1e8..bcf1faa08 100644
--- a/pyramid/tests/test_config/test_views.py
+++ b/pyramid/tests/test_config/test_views.py
@@ -115,6 +115,7 @@ class TestViewsConfigurationMixin(unittest.TestCase):
         self.assertEqual(wrapper.__module__, view.__module__)
         self.assertEqual(wrapper.__name__, view.__name__)
         self.assertEqual(wrapper.__doc__, view.__doc__)
+        self.assertEqual(wrapper.__discriminator__(None, None)[0], 'view')
 
     def test_add_view_view_callable_dottedname(self):
         from pyramid.renderers import null_renderer
@@ -875,6 +876,41 @@ class TestViewsConfigurationMixin(unittest.TestCase):
         request.params = {'param':'1'}
         self.assertEqual(wrapper(ctx, request), 'view8')
 
+    def test_add_view_multiview___discriminator__(self):
+        from pyramid.renderers import null_renderer
+        from zope.interface import Interface
+        class IFoo(Interface):
+            pass
+        class IBar(Interface):
+            pass
+        @implementer(IFoo)
+        class Foo(object):
+            pass
+        @implementer(IBar)
+        class Bar(object):
+            pass
+        foo = Foo()
+        bar = Bar()
+            
+        from pyramid.interfaces import IRequest
+        from pyramid.interfaces import IView
+        from pyramid.interfaces import IViewClassifier
+        from pyramid.interfaces import IMultiView
+        view = lambda *arg: 'OK'
+        view.__phash__ = 'abc'
+        config = self._makeOne(autocommit=True)
+        config.registry.registerAdapter(
+            view, (IViewClassifier, IRequest, Interface), IView, name='')
+        config.add_view(view=view, renderer=null_renderer,
+                        containment=IFoo)
+        config.add_view(view=view, renderer=null_renderer,
+                        containment=IBar)
+        wrapper = self._getViewCallable(config)
+        self.assertTrue(IMultiView.providedBy(wrapper))
+        request = self._makeRequest(config)
+        self.assertEqual(wrapper.__discriminator__(foo, request)[5], IFoo)
+        self.assertEqual(wrapper.__discriminator__(bar, request)[5], IBar)
+
     def test_add_view_with_template_renderer(self):
         from pyramid.tests import test_config
         from pyramid.interfaces import ISettings