Ticket #8309: genericforeignkey_fail_in_abstract_models_r8507.diff

django/db/models/base.py

@@ -95 +95 @@
                 # Things without _meta aren't functional models, so they're
                 # uninteresting parents.
                 continue
+            field_names = set([f.name for f in new_class._meta.local_fields + \
+                    new_class._meta.virtual_fields + \
+                    new_class._meta.many_to_many ])
             if not base._meta.abstract:
                 if base in o2o_map:
                     field = o2o_map[base]
@@ -108 +111 @@
                 new_class._meta.parents[base] = field
             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:
+                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))
-
+            # checking for virtual fields, like GenericForeignKey (see #8309)
+            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

django/db/models/options.py

@@ -26 +26 @@
 class Options(object):
     def __init__(self, meta, app_label=None):
         self.local_fields, self.local_many_to_many = [], []
+        self.virtual_fields = []
         self.module_name, self.verbose_name = None, None
         self.verbose_name_plural = None
         self.db_table = ''
@@ -152 +153 @@
         if hasattr(self, '_name_map'):
             del self._name_map
 
+    def add_virtual_field(self, field):
+        self.virtual_fields.append(field)
+
     def setup_pk(self, field):
         if not self.pk and field.primary_key:
             self.pk = field

django/contrib/contenttypes/generic.py

@@ -28 +28 @@
     def contribute_to_class(self, cls, name):
         # Make sure the fields exist (these raise FieldDoesNotExist,
         # which is a fine error to raise here)
+        cls._meta.add_virtual_field(self)
         self.name = name
+        self.attname = name
         self.model = cls
         self.cache_attr = "_%s_cache" % name
 

tests/modeltests/generic_relations/models.py

@@ -75 +75 @@
     def __unicode__(self):
         return self.name
 
+class ValuableTaggedItem(TaggedItem):
+    value = models.PositiveSmallIntegerField()
+
+
 __test__ = {'API_TESTS':"""
 # Create the world in 7 lines of code...
 >>> lion = Animal(common_name="Lion", latin_name="Panthera leo")
@@ -211 +215 @@
 <p><label for="id_generic_relations-taggeditem-content_type-object_id-1-tag">Tag:</label> <input id="id_generic_relations-taggeditem-content_type-object_id-1-tag" type="text" name="generic_relations-taggeditem-content_type-object_id-1-tag" maxlength="50" /></p>
 <p><label for="id_generic_relations-taggeditem-content_type-object_id-1-DELETE">Delete:</label> <input type="checkbox" name="generic_relations-taggeditem-content_type-object_id-1-DELETE" id="id_generic_relations-taggeditem-content_type-object_id-1-DELETE" /><input type="hidden" name="generic_relations-taggeditem-content_type-object_id-1-id" id="id_generic_relations-taggeditem-content_type-object_id-1-id" /></p>
 
+# GenericForeignKey should work with abstract classes (see #8309) #############
+
+>>> valuedtag = ValuableTaggedItem(content_object=quartz, tag="shiny", value=10)
+
 """}