edit

Author: timgraham

django_mongodb_backend/fields/auto.py

@@ -22,22 +22,17 @@ def deconstruct(self):
         return name, path, args, kwargs
 
     def get_prep_value(self, value):
-        if value is None or isinstance(value, ObjectId):
-            return value
-        try:
-            return ObjectId(value)
-        except errors.InvalidId as e:
-            raise ValueError(f"Field '{self.name}' expected an ObjectId but got {value!r}.") from e
+        return self.to_python(value)
 
     def get_internal_type(self):
         return "ObjectIdAutoField"
 
     def to_python(self, value):
-        if value is None or isinstance(value, int):
+        if value is None:
             return value
         try:
             return ObjectId(value)
-        except errors.InvalidId:
+        except (errors.InvalidId, TypeError):
             raise exceptions.ValidationError(
                 self.error_messages["invalid"],
                 code="invalid",