Fix changeform_view() redirection to the child admin site.

This method is normally called from `add_view()` and `change_view()`.
However, some third party modules (such as django-reversion) call this
method directly. By redirecting those calls to the child admin, their
views also display the proper admin views.

docs/changelog.rst

@@ -1,6 +1,14 @@
 Changelog
 =========
 
+Changes in git
+--------------
+
+* Fixed support for ``PolymorphicManager.from_queryset()`` for custom query sets.
+* Fixed Django 1.7 ``changeform_view()`` redirection to the child admin site.
+  This fixes custom admin code that uses these views, such as django-reversion_'s ``revision_view()`` / ``recover_view()``.
+
+
 Version 0.9 (2016-02-17)
 ------------------------
 
@@ -9,7 +17,7 @@ Version 0.9 (2016-02-17)
 * Fix Django 1.9 handling of custom URLs.
   The new change-URL redirect overlapped any custom URLs defined in the child admin.
 * Fix Django 1.9 support in the admin.
-* Fix missing ``history_view`` redirection to the child admin, which is important for django-reversion_ support.
+* Fix missing ``history_view()`` redirection to the child admin, which is important for django-reversion_ support.
   See the documentation for hints for :ref:`django-reversion-compare support <django-reversion-compare-support>`.
 
 

polymorphic/admin.py

@@ -262,6 +262,18 @@ class PolymorphicParentModelAdmin(admin.ModelAdmin):
         real_admin = self._get_real_admin(object_id)
         return real_admin.change_view(request, object_id, *args, **kwargs)
 
+    if django.VERSION >= (1, 7):
+        def changeform_view(self, request, object_id=None, *args, **kwargs):
+            # The `changeform_view` is available as of Django 1.7, combining the add_view and change_view.
+            # As it's directly called by django-reversion, this method is also overwritten to make sure it
+            # also redirects to the child admin.
+            if object_id:
+                real_admin = self._get_real_admin(object_id)
+                return real_admin.changeform_view(request, object_id, *args, **kwargs)
+            else:
+                # Add view. As it should already be handled via `add_view`, this means something custom is done here!
+                return super(PolymorphicParentModelAdmin, self).changeform_view(request, object_id, *args, **kwargs)
+
     def history_view(self, request, object_id, extra_context=None):
         """Redirect the history view to the real admin."""
         real_admin = self._get_real_admin(object_id)