From efc1c73bf511cbebf03fa5b13fa3a98718daf928 Mon Sep 17 00:00:00 2001
From: Taoup <mahongtao0x7e0@163.com>
Date: Wed, 29 Jan 2020 23:06:56 +0800
Subject: [PATCH] Simplified DeferredAttribute.__get__() a bit.

---
 django/db/models/query_utils.py | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/django/db/models/query_utils.py b/django/db/models/query_utils.py
index 96409cc67ce..4c6c48bf9d3 100644
--- a/django/db/models/query_utils.py
+++ b/django/db/models/query_utils.py
@@ -141,7 +141,7 @@ class DeferredAttribute:
             return self
         data = instance.__dict__
         field_name = self.field.attname
-        if data.get(field_name, self) is self:
+        if field_name not in data:
             # Let's see if the field is part of the parent chain. If so we
             # might be able to reuse the already loaded value. Refs #18343.
             val = self._check_parent_chain(instance)