Ticket #17875: foreignkey-db-using.patch

related.py

@@ -836 +836 @@
     def validate(self, value, model_instance):
         if self.rel.parent_link:
             return
         super(ForeignKey, self).validate(value, model_instance)
         if value is None:
             return
 
-        using = router.db_for_read(model_instance.__class__, instance=model_instance)
+        using = router.db_for_read(self.rel.to, instance=model_instance)
         qs = self.rel.to._default_manager.using(using).filter(
                 **{self.rel.field_name: value}
              )
         qs = qs.complex_filter(self.rel.limit_choices_to)
         if not qs.exists():
             raise exceptions.ValidationError(self.error_messages['invalid'] % {
                 'model': self.rel.to._meta.verbose_name, 'pk': value})