Fixed #11319 - Added lookup support for ForeignKey.to_field. Also reverted no-longer-needed model formsets workaround for lack of such support from r10756. Thanks Russell and Alex for review.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@15303 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/models/fields/related.py

@@ -178,9 +178,20 @@ class RelatedField(object):
         # the primary key may itself be an object - so we need to keep drilling
         # down until we hit a value that can be used for a comparison.
         v = value
+
+        # In the case of an FK to 'self', this check allows to_field to be used
+        # for both forwards and reverse lookups across the FK. (For normal FKs,
+        # it's only relevant for forward lookups).
+        if isinstance(v, self.rel.to):
+            field_name = getattr(self.rel, "field_name", None)
+        else:
+            field_name = None
         try:
             while True:
-                v = getattr(v, v._meta.pk.name)
+                if field_name is None:
+                    field_name = v._meta.pk.name
+                v = getattr(v, field_name)
+                field_name = None
         except AttributeError:
             pass
         except exceptions.ObjectDoesNotExist:

django/db/models/sql/query.py

@@ -1364,7 +1364,12 @@ class Query(object):
                         table = opts.db_table
                         from_col = local_field.column
                         to_col = field.column
-                        target = opts.pk
+                        # In case of a recursive FK, use the to_field for
+                        # reverse lookups as well
+                        if orig_field.model is local_field.model:
+                            target = opts.get_field(field.rel.field_name)
+                        else:
+                            target = opts.pk
                         orig_opts._join_cache[name] = (table, from_col, to_col,
                                 opts, target)
 

django/forms/models.py

@@ -700,13 +700,9 @@ class BaseInlineFormSet(BaseModelFormSet):
         self.save_as_new = save_as_new
         # is there a better way to get the object descriptor?
         self.rel_name = RelatedObject(self.fk.rel.to, self.model, self.fk).get_accessor_name()
-        if self.fk.rel.field_name == self.fk.rel.to._meta.pk.name:
-            backlink_value = self.instance
-        else:
-            backlink_value = getattr(self.instance, self.fk.rel.field_name)
         if queryset is None:
             queryset = self.model._default_manager
-        qs = queryset.filter(**{self.fk.name: backlink_value})
+        qs = queryset.filter(**{self.fk.name: self.instance})
         super(BaseInlineFormSet, self).__init__(data, files, prefix=prefix,
                                                 queryset=qs)