Protocol.for_id: handle null Object.source_protocol

protocol.py

@@ -175,8 +175,9 @@ class Protocol:
             logger.info(f'Trying {protocol.__name__}')
             try:
                 obj = protocol.load(id)
-                logger.info(f"Looks like it's {obj.source_protocol}")
-                return PROTOCOLS[obj.source_protocol]
+                if obj.source_protocol:
+                    logger.info(f"{obj.key} has source_protocol {obj.source_protocol}")
+                    return PROTOCOLS[obj.source_protocol]
             except werkzeug.exceptions.HTTPException:
                 # internal error we generated ourselves; try next protocol
                 pass
@@ -185,7 +186,7 @@ class Protocol:
                 if code:
                     # we tried and failed fetching the id over the network
                     return None
-                logger.info(e)
+                raise
 
         logger.info(f'No matching protocol found for {id} !')
         return None

tests/test_protocol.py

@@ -131,6 +131,10 @@ class ProtocolTest(TestCase):
         Object(id='http://ui/obj', source_protocol='ui').put()
         self.assertEqual(UIProtocol, Protocol.for_id('http://ui/obj'))
 
+    def test_for_id_object_missing_source_protocol(self):
+        Object(id='http://bad/obj').put()
+        self.assertIsNone(Protocol.for_id('http://bad/obj'))
+
     @patch('requests.get')
     def test_for_id_activitypub_fetch(self, mock_get):
         mock_get.return_value = self.as2_resp(ACTOR)