Ticket #5622: 5622.patch

django/db/models/fields/__init__.py

@@ -888 +888 @@
         defaults.update(kwargs)
         return super(IPAddressField, self).formfield(**defaults)
 
+    def get_db_prep_save(self, value):
+        return value or None
+
 class NullBooleanField(Field):
     empty_strings_allowed = False
     def __init__(self, *args, **kwargs):