Added FutureWarning for inherited classes not declaring allow_inheritance

Refs #437

docs/changelog.rst

@@ -5,6 +5,7 @@ Changelog
 Changes in 0.6
 ==============
 
+- Added FutureWarning to inherited classes not declaring 'allow_inheritance' as the default will change in 0.7
 - Added support for covered indexes when inheritance is off
 - No longer always upsert on save for items with a '_id'
 - Error raised if update doesn't have an operation

mongoengine/base.py

@@ -1,3 +1,5 @@
+import warnings
+
 from queryset import QuerySet, QuerySetManager
 from queryset import DoesNotExist, MultipleObjectsReturned
 from queryset import DO_NOTHING
@@ -116,7 +118,6 @@ class BaseField(object):
                  validation=None, choices=None, verbose_name=None, help_text=None):
         self.db_field = (db_field or name) if not primary_key else '_id'
         if name:
-            import warnings
             msg = "Fields' 'name' attribute deprecated in favour of 'db_field'"
             warnings.warn(msg, DeprecationWarning)
         self.name = None
@@ -471,7 +472,6 @@ class DocumentMetaclass(type):
     """Metaclass for all documents.
     """
 
-
     def __new__(cls, name, bases, attrs):
         def _get_mixin_fields(base):
             attrs = {}
@@ -512,6 +512,13 @@ class DocumentMetaclass(type):
                 # inheritance may be disabled to remove dependency on
                 # additional fields _cls and _types
                 class_name.append(base._class_name)
+                if not base._meta.get('allow_inheritance_defined', True):
+                    warnings.warn(
+                        "%s uses inheritance, the default for allow_inheritance "
+                        "is changing to off by default.  Please add it to the "
+                        "document meta." % name,
+                        FutureWarning
+                    )
                 if base._meta.get('allow_inheritance', True) == False:
                     raise ValueError('Document %s may not be subclassed' %
                                      base.__name__)
@@ -673,6 +680,10 @@ class TopLevelDocumentMetaclass(DocumentMetaclass):
             'delete_rules': {},
             'allow_inheritance': True
         }
+
+        allow_inheritance_defined = ('allow_inheritance' in base_meta or
+                                     'allow_inheritance'in attrs.get('meta', {}))
+        meta['allow_inheritance_defined'] = allow_inheritance_defined
         meta.update(base_meta)
 
         # Apply document-defined meta options

setup.py

@@ -39,7 +39,7 @@ setup(name='mongoengine',
       author='Harry Marr',
       author_email='harry.marr@{nospam}gmail.com',
       maintainer="Ross Lawley",
-      maintainer_email="ross.lawley@gmail.com",
+      maintainer_email="ross.lawley@{nospam}gmail.com",
       url='http://mongoengine.org/',
       license='MIT',
       include_package_data=True,

tests/document.py

@@ -23,11 +23,32 @@ class DocumentTest(unittest.TestCase):
         class Person(Document):
             name = StringField()
             age = IntField()
+
+            meta = {'allow_inheritance': True}
+
         self.Person = Person
 
     def tearDown(self):
         self.Person.drop_collection()
 
+    def test_future_warning(self):
+        """Add FutureWarning for future allow_inhertiance default change.
+        """
+
+        with warnings.catch_warnings(True) as errors:
+
+            class SimpleBase(Document):
+                a = IntField()
+
+            class InheritedClass(SimpleBase):
+                b = IntField()
+
+            InheritedClass()
+            self.assertEquals(len(errors), 1)
+            warning = errors[0]
+            self.assertEquals(FutureWarning, warning.category)
+            self.assertTrue("InheritedClass" in warning.message.message)
+
     def test_drop_collection(self):
         """Ensure that the collection may be dropped from the database.
         """
@@ -145,7 +166,8 @@ class DocumentTest(unittest.TestCase):
     def test_get_superclasses(self):
         """Ensure that the correct list of superclasses is assembled.
         """
-        class Animal(Document): pass
+        class Animal(Document):
+            meta = {'allow_inheritance': True}
         class Fish(Animal): pass
         class Mammal(Animal): pass
         class Human(Mammal): pass
@@ -194,7 +216,8 @@ class DocumentTest(unittest.TestCase):
 
     def test_polymorphic_queries(self):
         """Ensure that the correct subclasses are returned from a query"""
-        class Animal(Document): pass
+        class Animal(Document):
+            meta = {'allow_inheritance': True}
         class Fish(Animal): pass
         class Mammal(Animal): pass
         class Human(Mammal): pass
@@ -223,7 +246,8 @@ class DocumentTest(unittest.TestCase):
         """Ensure that the correct subclasses are returned from a query when
         using references / generic references
         """
-        class Animal(Document): pass
+        class Animal(Document):
+            meta = {'allow_inheritance': True}
         class Fish(Animal): pass
         class Mammal(Animal): pass
         class Human(Mammal): pass
@@ -302,7 +326,8 @@ class DocumentTest(unittest.TestCase):
                          self.Person._get_collection_name())
 
         # Ensure that MRO error is not raised
-        class A(Document): pass
+        class A(Document):
+            meta = {'allow_inheritance': True}
         class B(A): pass
         class C(B): pass
 
@@ -597,6 +622,7 @@ class DocumentTest(unittest.TestCase):
                     'tags',
                     ('category', '-date')
                 ],
+                'allow_inheritance': True
             }
 
         BlogPost.drop_collection()
@@ -996,6 +1022,8 @@ class DocumentTest(unittest.TestCase):
             username = StringField(primary_key=True)
             name = StringField()
 
+            meta = {'allow_inheritance': True}
+
         User.drop_collection()
 
         self.assertEqual(User._fields['username'].db_field, '_id')
@@ -1045,6 +1073,8 @@ class DocumentTest(unittest.TestCase):
         class Place(Document):
             name = StringField()
 
+            meta = {'allow_inheritance': True}
+
         class NicePlace(Place):
             pass
 

tests/dynamic_document.py

@@ -12,6 +12,7 @@ class DynamicDocTest(unittest.TestCase):
 
         class Person(DynamicDocument):
             name = StringField()
+            meta = {'allow_inheritance': True}
 
         Person.drop_collection()
 

tests/fixtures.py

@@ -20,4 +20,4 @@ class Mixin(object):
 
 
 class Base(Document):
-    pass
+    meta = {'allow_inheritance': True}

tests/queryset.py

@@ -20,6 +20,7 @@ class QuerySetTest(unittest.TestCase):
         class Person(Document):
             name = StringField()
             age = IntField()
+            meta = {'allow_inheritance': True}
         self.Person = Person
 
     def test_initialisation(self):