Fixed #10405 -- Raise a more useful error if the formfield of a related model field can't be created yet because the related model isn't loaded yet. Thanks ojii and charstring.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@16604 bcc190cf-cafb-0310-a4f2-bffc1f526a37

2 files changed, 5 insertions, 1 deletions

diff --git a/django/core/exceptions.py b/django/core/exceptions.py
index 21be8702fa..201a854a4b 100644
--- a/django/core/exceptions.py
+++ b/django/core/exceptions.py
@@ -3,7 +3,7 @@ Global Django exception and warning classes.
 """
 
 class DjangoRuntimeWarning(RuntimeWarning):
-   pass
+    pass
 
 class ObjectDoesNotExist(Exception):
     "The requested object does not exist"
diff --git a/django/db/models/fields/related.py b/django/db/models/fields/related.py
index e7f4b9b3de..3e861cddd2 100644
--- a/django/db/models/fields/related.py
+++ b/django/db/models/fields/related.py
@@ -905,6 +905,10 @@ class ForeignKey(RelatedField, Field):
 
     def formfield(self, **kwargs):
         db = kwargs.pop('using', None)
+        if isinstance(self.rel.to, basestring):
+            raise ValueError("Cannot create form field for %r yet, because "
+                             "its related model %r has not been loaded yet" %
+                             (self.name, self.rel.to))
         defaults = {
             'form_class': forms.ModelChoiceField,
             'queryset': self.rel.to._default_manager.using(db).complex_filter(self.rel.limit_choices_to),