Ticket #15279: multiple_abstract_inheritance_r15458.diff

django/db/models/fields/__init__.py

@@ -234 +234 @@
     def contribute_to_class(self, cls, name):
         self.set_attributes_from_name(name)
         self.model = cls
+        if not hasattr(self, "_declared_on_class"):
+            self._declared_on_class = cls
+        if not hasattr(self, "_first_concrete_class") and not cls._meta.abstract:
+            self._first_concrete_class = cls
         cls._meta.add_field(self)
         if self.choices:
             setattr(cls, 'get_%s_display' % self.name, curry(cls._get_FIELD_display, field=self))

django/db/models/options.py

@@ -152 +152 @@
         # Insert the given field in the order in which it was created, using
         # the "creation_counter" attribute of the field.
         # Move many-to-many related fields from self.fields into
-        # self.many_to_many.
+        # self.many_to_many. Ignore duplicate fields inherited from a
+        # single abstract base class.
+        try:
+            f = self.get_field(field.name)
+        except FieldDoesNotExist:
+            pass
+        else:
+            if f._declared_on_class == field._declared_on_class and getattr(f, '_first_concrete_class', None) == getattr(field, '_first_concrete_class', None):
+                return
+
         if field.rel and isinstance(field.rel, ManyToManyRel):
             self.local_many_to_many.insert(bisect(self.local_many_to_many, field), field)
             if hasattr(self, '_m2m_cache'):