Merge pull request #763 from LincolnPuzey/fix_raising_exception

Fix edge case where `None` would be raised as exception in `StubBroker.join()`

Author: LincolnPuzey

dramatiq/brokers/stub.py

@@ -173,7 +173,7 @@ def join(self, queue_name: str, *, timeout: Optional[int] = None, fail_fast: boo
             else:
                 if fail_fast:
                     for message in self.dead_letters_by_queue[queue_name]:
-                        raise message._exception from None
+                        raise (message._exception or Exception("Message failed with unknown error")) from None
 
                 return
 

dramatiq/worker.py

@@ -364,13 +364,14 @@ def handle_message(self, message: MessageProxy) -> None:
                 actor = self.broker.get_actor(message.actor_name)
                 self.logger.debug("Pushing message %r onto work queue.", message.message_id)
                 self.work_queue.put((actor.priority, message))
-        except ActorNotFound:
+        except ActorNotFound as e:
             self.logger.error(
                 "Received message for undefined actor %r. Moving it to the DLQ.",
                 message.actor_name,
                 exc_info=True,
             )
             message.fail()
+            message.stuff_exception(e)
             self.post_process_message(message)
 
     def post_process_message(self, message: MessageProxy) -> None:

tests/test_actors.py

@@ -9,7 +9,7 @@
 
 import dramatiq
 from dramatiq import Message, Middleware
-from dramatiq.errors import RateLimitExceeded
+from dramatiq.errors import ActorNotFound, RateLimitExceeded
 from dramatiq.middleware import CurrentMessage, SkipMessage
 
 from .common import skip_on_pypy, worker
@@ -316,7 +316,8 @@ def test_messages_belonging_to_missing_actors_are_rejected(stub_broker, stub_wor
     stub_broker.enqueue(message)
 
     # Then join on the queue
-    stub_broker.join("some-queue")
+    with pytest.raises(ActorNotFound, match=r"^some-actor$"):
+        stub_broker.join("some-queue", fail_fast=True)
     stub_worker.join()
 
     # I expect the message to end up on the dead letter queue