adds fix for SingleObjectTemplateResponseMixin raising a TemplateDoes…

…NotExist when it should have raised an ImproperlyConfigured. fixes 16502. by @ianawilson, @jambonrose

django/views/generic/detail.py

@@ -137,28 +137,34 @@ def get_template_names(self):
             # we just start with an empty list.
             names = []
 
-        # If self.template_name_field is set, grab the value of the field
-        # of that name from the object; this is the most specific template
-        # name, if given.
-        if self.object and self.template_name_field:
-            name = getattr(self.object, self.template_name_field, None)
-            if name:
-                names.insert(0, name)
-
-        # The least-specific option is the default <app>/<model>_detail.html;
-        # only use this if the object in question is a model.
-        if isinstance(self.object, models.Model):
-            names.append("%s/%s%s.html" % (
-                self.object._meta.app_label,
-                self.object._meta.model_name,
-                self.template_name_suffix
-            ))
-        elif hasattr(self, 'model') and self.model is not None and issubclass(self.model, models.Model):
-            names.append("%s/%s%s.html" % (
-                self.model._meta.app_label,
-                self.model._meta.model_name,
-                self.template_name_suffix
-            ))
+            # If self.template_name_field is set, grab the value of the field
+            # of that name from the object; this is the most specific template
+            # name, if given.
+            if self.object and self.template_name_field:
+                name = getattr(self.object, self.template_name_field, None)
+                if name:
+                    names.insert(0, name)
+
+            # The least-specific option is the default <app>/<model>_detail.html;
+            # only use this if the object in question is a model.
+            if isinstance(self.object, models.Model):
+                names.append("%s/%s%s.html" % (
+                    self.object._meta.app_label,
+                    self.object._meta.model_name,
+                    self.template_name_suffix
+                ))
+            elif hasattr(self, 'model') and self.model is not None and issubclass(self.model, models.Model):
+                names.append("%s/%s%s.html" % (
+                    self.model._meta.app_label,
+                    self.model._meta.model_name,
+                    self.template_name_suffix
+                ))
+
+            # If we still haven't managed to find any template names, we should
+            # re-raise the ImproperlyConfigured to alert the user.
+            if not names:
+                raise
+
         return names
 
 

tests/generic_views/test_base.py

@@ -468,3 +468,15 @@ def test_overwrite_queryset(self):
         # Overwrite the view's queryset with queryset from kwarg
         context = test_view.get_context_data(object_list=queryset)
         self.assertEqual(context['object_list'], queryset)
+
+
+class SingleObjectTemplateResponseMixinTest(unittest.TestCase):
+
+    def test_create_view_with_form_only(self):
+        """
+        We want to makes sure that if you use a template mixin, but forget the
+        template, it still tells you it's ImproperlyConfigured instead of
+        TemplateDoesNotExist.
+        """
+        view = views.TemplateResponseWithoutTemplate()
+        self.assertRaises(ImproperlyConfigured, view.get_template_names)

tests/generic_views/views.py

@@ -92,6 +92,14 @@ class NaiveAuthorCreate(generic.CreateView):
     fields = '__all__'
 
 
+class TemplateResponseWithoutTemplate(generic.detail.SingleObjectTemplateResponseMixin, generic.View):
+    # we don't define the usual template_name here
+
+    def __init__(self):
+        # Dummy object, but attr is required by get_template_name()
+        self.object = None
+
+
 class AuthorCreate(generic.CreateView):
     model = Author
     success_url = '/list/authors/'