Protocol.receive: post age bug fix, handle missing timezone

fixes https://console.cloud.google.com/errors/detail/CIXMq_WGs6KuSQ;locations=global;time=P30D?project=bridgy-federated

protocol.py

@@ -1,6 +1,6 @@
 """Base protocol class and common code."""
 import copy
-from datetime import datetime, timedelta
+from datetime import datetime, timedelta, timezone
 import logging
 import os
 import re
@@ -965,7 +965,10 @@ class Protocol:
         if obj.type == 'post':
             if published := inner_obj_as1.get('published'):
                 try:
-                    age = util.now() - util.parse_iso8601(published)
+                    published_dt = util.parse_iso8601(published)
+                    if not published_dt.tzinfo:
+                        published_dt = published_dt.replace(tzinfo=timezone.utc)
+                    age = util.now() - published_dt
                     if age > CREATE_MAX_AGE:
                         error(f'Ignoring, too old, {age} is over {CREATE_MAX_AGE}',
                               status=204)

tests/test_protocol.py

@@ -3050,6 +3050,21 @@ class ProtocolReceiveTest(TestCase):
         self.assertEqual([], Fake.sent)
         self.assertEqual([], OtherFake.sent)
 
+    def test_too_old_published_without_timezone(self):
+        Follower.get_or_create(to=self.user, from_=self.alice)
+
+        with self.assertRaises(NoContent):
+            Fake.receive_as1({
+                'id': 'fake:post',
+                'objectType': 'note',
+                'author': 'fake:user',
+                'published': '2021-12-14T03:04:05',  # NOW - 2w
+            })
+        self.assertIsNone(Object.get_by_id('fake:post'))
+
+        self.assertEqual([], Fake.sent)
+        self.assertEqual([], OtherFake.sent)
+
     def test_receive_activity_lease(self):
         Follower.get_or_create(to=self.user, from_=self.alice)