Refs #27468 -- Added tests and release notes for signing.dumps()/loads() changes.

Follow up to 71c4fb7beb.

docs/internals/deprecation.txt

@@ -76,6 +76,10 @@ details on these changes.
 * Support for the pre-Django 3.1 ``django.core.signing.Signer`` signatures
   (encoded with the SHA-1 algorithm) will be removed.
 
+* Support for the pre-Django 3.1 ``django.core.signing.dumps()`` signatures
+  (encoded with the SHA-1 algorithm) in ``django.core.signing.loads()`` will be
+  removed.
+
 * Support for the pre-Django 3.1 user sessions (that use the SHA-1 algorithm)
   will be removed.
 

docs/releases/3.1.txt

@@ -418,9 +418,10 @@ Security
   origins. If you need the previous behavior, explicitly set
   :setting:`SECURE_REFERRER_POLICY` to ``None``.
 
-* The default :class:`django.core.signing.Signer` algorithm is changed to the
+* The default algorithm of :class:`django.core.signing.Signer`,
-  SHA-256. Support for signatures made with the old SHA-1 algorithm remains
+  :meth:`django.core.signing.loads`, and :meth:`django.core.signing.dumps` is
-  until Django 4.0.
+  changed to the SHA-256. Support for signatures made with the old SHA-1
+  algorithm remains until Django 4.0.
 
   Also, the new ``algorithm`` parameter of the
   :class:`~django.core.signing.Signer` allows customizing the hashing

docs/topics/signing.txt

@@ -187,8 +187,8 @@ and tuples) if you pass in a tuple, you will get a list from
 
 .. function:: dumps(obj, key=None, salt='django.core.signing', serializer=JSONSerializer, compress=False)
 
-    Returns URL-safe, sha1 signed base64 compressed JSON string. Serialized
+    Returns URL-safe, signed base64 compressed JSON string. Serialized object
-    object is signed using :class:`~TimestampSigner`.
+    is signed using :class:`~TimestampSigner`.
 
 .. function:: loads(string, key=None, salt='django.core.signing', serializer=JSONSerializer, max_age=None)
 

tests/signing/tests.py

@@ -126,6 +126,13 @@ class TestSigner(SimpleTestCase):
             self.assertNotEqual(o, signing.dumps(o, compress=True))
             self.assertEqual(o, signing.loads(signing.dumps(o, compress=True)))
 
+    def test_dumps_loads_legacy_signature(self):
+        # RemovedInDjango40Warning: pre-Django 3.1 signatures won't be
+        # supported.
+        value = 'a string \u2020'
+        signed = signing.dumps(value, algorithm='sha1')
+        self.assertEqual(signing.loads(signed), value)
+
     def test_decode_detects_tampering(self):
         "loads should raise exception for tampered objects"
         transforms = (