Fixed register_delete_rule inheritance issue

mongoengine/base/metaclasses.py

@@ -140,8 +140,31 @@ class DocumentMetaclass(type):
                 base._subclasses += (_cls,)
             base._types = base._subclasses   # TODO depreciate _types
 
-        # Handle delete rules
         Document, EmbeddedDocument, DictField = cls._import_classes()
+
+        if issubclass(new_class, Document):
+            new_class._collection = None
+
+        # Add class to the _document_registry
+        _document_registry[new_class._class_name] = new_class
+
+        # In Python 2, User-defined methods objects have special read-only
+        # attributes 'im_func' and 'im_self' which contain the function obj
+        # and class instance object respectively.  With Python 3 these special
+        # attributes have been replaced by __func__ and __self__.  The Blinker
+        # module continues to use im_func and im_self, so the code below
+        # copies __func__ into im_func and __self__ into im_self for
+        # classmethod objects in Document derived classes.
+        if PY3:
+            for key, val in new_class.__dict__.items():
+                if isinstance(val, classmethod):
+                    f = val.__get__(new_class)
+                    if hasattr(f, '__func__') and not hasattr(f, 'im_func'):
+                        f.__dict__.update({'im_func': getattr(f, '__func__')})
+                    if hasattr(f, '__self__') and not hasattr(f, 'im_self'):
+                        f.__dict__.update({'im_self': getattr(f, '__self__')})
+
+        # Handle delete rules
         for field in new_class._fields.itervalues():
             f = field
             f.owner_document = new_class
@@ -172,28 +195,6 @@ class DocumentMetaclass(type):
                        "field name" % field.name)
                 raise InvalidDocumentError(msg)
 
-        if issubclass(new_class, Document):
-            new_class._collection = None
-
-        # Add class to the _document_registry
-        _document_registry[new_class._class_name] = new_class
-
-        # In Python 2, User-defined methods objects have special read-only
-        # attributes 'im_func' and 'im_self' which contain the function obj
-        # and class instance object respectively.  With Python 3 these special
-        # attributes have been replaced by __func__ and __self__.  The Blinker
-        # module continues to use im_func and im_self, so the code below
-        # copies __func__ into im_func and __self__ into im_self for
-        # classmethod objects in Document derived classes.
-        if PY3:
-            for key, val in new_class.__dict__.items():
-                if isinstance(val, classmethod):
-                    f = val.__get__(new_class)
-                    if hasattr(f, '__func__') and not hasattr(f, 'im_func'):
-                        f.__dict__.update({'im_func': getattr(f, '__func__')})
-                    if hasattr(f, '__self__') and not hasattr(f, 'im_self'):
-                        f.__dict__.update({'im_self': getattr(f, '__self__')})
-
         return new_class
 
     def add_to_class(self, name, value):

tests/document/class_methods.py

@@ -5,7 +5,7 @@ import unittest
 
 from mongoengine import *
 
-from mongoengine.queryset import NULLIFY
+from mongoengine.queryset import NULLIFY, PULL
 from mongoengine.connection import get_db
 
 __all__ = ("ClassMethodsTest", )
@@ -85,6 +85,25 @@ class ClassMethodsTest(unittest.TestCase):
         self.assertEqual(self.Person._meta['delete_rules'],
                          {(Job, 'employee'): NULLIFY})
 
+    def test_register_delete_rule_inherited(self):
+
+        class Vaccine(Document):
+            name = StringField(required=True)
+
+            meta = {"indexes": ["name"]}
+
+        class Animal(Document):
+            family = StringField(required=True)
+            vaccine_made = ListField(ReferenceField("Vaccine", reverse_delete_rule=PULL))
+
+            meta = {"allow_inheritance": True, "indexes": ["family"]}
+
+        class Cat(Animal):
+            name = StringField(required=True)
+
+        self.assertEqual(Vaccine._meta['delete_rules'][(Animal, 'vaccine_made')], PULL)
+        self.assertEqual(Vaccine._meta['delete_rules'][(Cat, 'vaccine_made')], PULL)
+
     def test_collection_naming(self):
         """Ensure that a collection with a specified name may be used.
         """