From 921e4ccb77ed2056d5cdfc6756ee82b54831937f Mon Sep 17 00:00:00 2001
From: Keryn Knight <keryn@kerynknight.com>
Date: Mon, 9 Aug 2021 12:28:40 +0100
Subject: [PATCH] Fixed #33003 -- Removed **kwargs from QuerySet._chain().

The functionality of updating the __dict__ was only present to allow
for pickling a Prefetch object, which is a comparably rare operation.
Forcing the __getstate__() implementation to handle it allows the
chaining operation to be slightly faster, which is much more common.
---
 django/db/models/query.py | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/django/db/models/query.py b/django/db/models/query.py
index 71a52fb754..88cfc3de38 100644
--- a/django/db/models/query.py
+++ b/django/db/models/query.py
@@ -1322,7 +1322,7 @@ class QuerySet:
                 self._insert(item, fields=fields, using=self.db, ignore_conflicts=ignore_conflicts)
         return inserted_rows
 
-    def _chain(self, **kwargs):
+    def _chain(self):
         """
         Return a copy of the current QuerySet that's ready for another
         operation.
@@ -1331,7 +1331,6 @@ class QuerySet:
         if obj._sticky_filter:
             obj.query.filter_is_sticky = True
             obj._sticky_filter = False
-        obj.__dict__.update(kwargs)
         return obj
 
     def _clone(self):
@@ -1622,11 +1621,11 @@ class Prefetch:
     def __getstate__(self):
         obj_dict = self.__dict__.copy()
         if self.queryset is not None:
+            queryset = self.queryset._chain()
             # Prevent the QuerySet from being evaluated
-            obj_dict['queryset'] = self.queryset._chain(
-                _result_cache=[],
-                _prefetch_done=True,
-            )
+            queryset._result_cache = []
+            queryset._prefetch_done = True
+            obj_dict['queryset'] = queryset
         return obj_dict
 
     def add_prefix(self, prefix):