From dca4c2ff764ab94848274952eee4319a638be1d2 Mon Sep 17 00:00:00 2001
From: Daniyal Abbasi <abbasi.daniyal98@gmail.com>
Date: Thu, 2 Sep 2021 11:15:40 +0200
Subject: [PATCH] Refs #33012 -- Moved PickleSerializer to
 django.core.serializers.base and added tests.

---
 django/contrib/sessions/serializers.py | 21 ++++-----------------
 django/core/serializers/base.py        | 16 ++++++++++++++++
 tests/serializers/tests.py             | 18 +++++++++++++++++-
 3 files changed, 37 insertions(+), 18 deletions(-)

diff --git a/django/contrib/sessions/serializers.py b/django/contrib/sessions/serializers.py
index 6ac4aab6a4..5b6c343daa 100644
--- a/django/contrib/sessions/serializers.py
+++ b/django/contrib/sessions/serializers.py
@@ -1,20 +1,7 @@
-import pickle
-
+from django.core.serializers.base import (
+    PickleSerializer as BasePickleSerializer,
+)
 from django.core.signing import JSONSerializer as BaseJSONSerializer
 
-
-class PickleSerializer:
-    """
-    Simple wrapper around pickle to be used in signing.dumps and
-    signing.loads.
-    """
-    protocol = pickle.HIGHEST_PROTOCOL
-
-    def dumps(self, obj):
-        return pickle.dumps(obj, self.protocol)
-
-    def loads(self, data):
-        return pickle.loads(data)
-
-
 JSONSerializer = BaseJSONSerializer
+PickleSerializer = BasePickleSerializer
diff --git a/django/core/serializers/base.py b/django/core/serializers/base.py
index 3fee7893df..3bd492ec09 100644
--- a/django/core/serializers/base.py
+++ b/django/core/serializers/base.py
@@ -1,6 +1,7 @@
 """
 Module for abstract serializer/unserializer base classes.
 """
+import pickle
 from io import StringIO
 
 from django.core.exceptions import ObjectDoesNotExist
@@ -9,6 +10,21 @@ from django.db import models
 DEFER_FIELD = object()
 
 
+class PickleSerializer:
+    """
+    Simple wrapper around pickle to be used in signing.dumps()/loads() and
+    cache backends.
+    """
+    def __init__(self, protocol=None):
+        self.protocol = pickle.HIGHEST_PROTOCOL if protocol is None else protocol
+
+    def dumps(self, obj):
+        return pickle.dumps(obj, self.protocol)
+
+    def loads(self, data):
+        return pickle.loads(data)
+
+
 class SerializerDoesNotExist(KeyError):
     """The requested serializer was not found."""
     pass
diff --git a/tests/serializers/tests.py b/tests/serializers/tests.py
index 439464980d..4bd6acd982 100644
--- a/tests/serializers/tests.py
+++ b/tests/serializers/tests.py
@@ -1,3 +1,4 @@
+import pickle
 from datetime import datetime
 from functools import partialmethod
 from io import StringIO
@@ -5,7 +6,7 @@ from unittest import mock, skipIf
 
 from django.core import serializers
 from django.core.serializers import SerializerDoesNotExist
-from django.core.serializers.base import ProgressBar
+from django.core.serializers.base import PickleSerializer, ProgressBar
 from django.db import connection, transaction
 from django.http import HttpResponse
 from django.test import SimpleTestCase, override_settings, skipUnlessDBFeature
@@ -418,6 +419,21 @@ class SerializersTransactionTestBase:
         self.assertEqual(art_obj.author.name, "Agnes")
 
 
+class PickleSerializerTests(SimpleTestCase):
+    def test_serializer_protocol(self):
+        serializer = PickleSerializer(protocol=3)
+        self.assertEqual(serializer.protocol, 3)
+        # If protocol is not provided, it defaults to pickle.HIGHEST_PROTOCOL
+        serializer = PickleSerializer()
+        self.assertEqual(serializer.protocol, pickle.HIGHEST_PROTOCOL)
+
+    def test_serializer_loads_dumps(self):
+        serializer = PickleSerializer()
+        test_data = 'test data'
+        dump = serializer.dumps(test_data)
+        self.assertEqual(serializer.loads(dump), test_data)
+
+
 def register_tests(test_class, method_name, test_func, exclude=()):
     """
     Dynamically create serializer tests to ensure that all registered