Fixed #8309: subclasses now inherit `GenericForeignKey` correctly. There's also now an internal API so that other "virtual fields" like GFK can be inherited as well. Thanks, msaelices.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@8855 bcc190cf-cafb-0310-a4f2-bffc1f526a37

1 files changed, 28 insertions, 6 deletions

diff --git a/django/db/models/base.py b/django/db/models/base.py
index 121626ca93..e23369bb67 100644
--- a/django/db/models/base.py
+++ b/django/db/models/base.py
@@ -87,6 +87,14 @@ class ModelBase(type):
                 # Things without _meta aren't functional models, so they're
                 # uninteresting parents.
                 continue
+                
+            # All the fields of any type declared on this model
+            new_fields = new_class._meta.local_fields + \
+                         new_class._meta.many_to_many + \
+                         new_class._meta.virtual_fields
+            field_names = set([f.name for f in new_fields])
+                
+            # Concrete classes...
             if not base._meta.abstract:
                 if base in o2o_map:
                     field = o2o_map[base]
@@ -98,13 +106,17 @@ class ModelBase(type):
                             auto_created=True, parent_link=True)
                     new_class.add_to_class(attr_name, field)
                 new_class._meta.parents[base] = field
+            
+            # .. and abstract ones.
             else:
-                # The abstract base class case.
-                names = set([f.name for f in new_class._meta.local_fields + new_class._meta.many_to_many])
-                for field in base._meta.local_fields + base._meta.local_many_to_many:
-                    if field.name in names:
-                        raise FieldError('Local field %r in class %r clashes with field of similar name from abstract base class %r'
-                                % (field.name, name, base.__name__))
+                # Check for clashes between locally declared fields and those on the ABC.
+                parent_fields = base._meta.local_fields + base._meta.local_many_to_many
+                for field in parent_fields:
+                    if field.name in field_names:
+                        raise FieldError('Local field %r in class %r clashes '\
+                                         'with field of similar name from '\
+                                         'abstract base class %r' % \
+                                            (field.name, name, base.__name__))
                     new_class.add_to_class(field.name, copy.deepcopy(field))
 
             # Inherit managers from the abstract base classes.
@@ -115,6 +127,16 @@ class ModelBase(type):
                 if not val or val is manager:
                     new_manager = manager._copy_to_model(new_class)
                     new_class.add_to_class(mgr_name, new_manager)
+        
+            # Inherit virtual fields (like GenericForeignKey) from the parent class
+            for field in base._meta.virtual_fields:
+                if base._meta.abstract and field.name in field_names:
+                    raise FieldError('Local field %r in class %r clashes '\
+                                     'with field of similar name from '\
+                                     'abstract base class %r' % \
+                                        (field.name, name, base.__name__))
+                new_class.add_to_class(field.name, copy.deepcopy(field))
+        
         if abstract:
             # Abstract base models can't be instantiated and don't appear in
             # the list of models for an app. We do the final setup for them a