Merge pull request #743 from ncopiy/allow-to-use-tree-queryset-as-man…

…ager

Allow to use TreeQuerySet as manager method to get TreeManager class

.gitignore

@@ -7,3 +7,5 @@ MANIFEST
 tests/mydatabase
 *.egg
 .eggs
+venv/
+.idea/

mptt/querysets.py

@@ -4,6 +4,15 @@
 
 
 class TreeQuerySet(models.query.QuerySet):
+    def as_manager(cls):
+        # Address the circular dependency between `Queryset` and `Manager`.
+        from mptt.managers import TreeManager
+        manager = TreeManager.from_queryset(cls)()
+        manager._built_with_as_manager = True
+        return manager
+    as_manager.queryset_only = True
+    as_manager = classmethod(as_manager)
+
     def get_descendants(self, *args, **kwargs):
         """
         Alias to `mptt.managers.TreeManager.get_queryset_descendants`.

tests/myapp/tests.py

@@ -14,6 +14,7 @@
 from django.contrib.admin.views.main import ChangeList
 from django.contrib.admin import ModelAdmin, site
 from mptt.admin import TreeRelatedFieldListFilter
+from mptt.querysets import TreeQuerySet
 
 try:
     from mock_django import mock_signal_receiver
@@ -1732,6 +1733,11 @@ def test_get_descendants(self):
                 Category.objects.filter(name="Nintendo Wii").get_descendants(include_self=True)],
         )
 
+    def test_as_manager(self):
+        self.assertTrue(
+            issubclass(TreeQuerySet.as_manager().__class__, TreeManager)
+        )
+
 
 class TreeManagerTestCase(TreeTestCase):