Fix not picking up result from falsy result (#107)

* Fix not picking up result from falsy result

* add test and docs

* typo

django_q/tasks.py

@@ -148,7 +148,7 @@ def result(task_id, wait=0, cached=Conf.CACHED):
     start = time()
     while True:
         r = Task.get_result(task_id)
-        if r:
+        if r is not None:
             return r
         if (time() - start) * 1000 >= wait >= 0:
             break

django_q/tests/tasks.py

@@ -46,6 +46,10 @@ def hello():
     return "hello"
 
 
+def return_falsy_value():
+    return []
+
+
 def result(obj):
     print(f"RESULT HOOK {obj.name} : {obj.result()}")
 

django_q/tests/test_cluster.py

@@ -141,6 +141,30 @@ def test_cluster(broker):
     broker.delete_queue()
 
 
+@pytest.mark.django_db
+def test_results(broker):
+    broker.list_key = "cluster_test:q"
+    broker.delete_queue()
+    a = async_task(
+        "django_q.tests.tasks.return_falsy_value",
+        broker=broker,
+    )
+
+    task_queue = Queue()
+    stop_event = Event()
+    stop_event.set()
+    pusher(task_queue, stop_event, broker=broker)
+    task_queue.put("STOP")
+    result_queue = Queue()
+    worker(task_queue, result_queue, Value("f", -1))
+    result_queue.put("STOP")
+    monitor(result_queue)
+
+    # should not loop indefinitely when a real value is returned
+    value = result(a, wait=-1)
+    assert value == []
+
+
 @pytest.mark.django_db
 def test_enqueue(broker, admin_user):
     broker.list_key = "cluster_test:q"

docs/tasks.rst

@@ -121,6 +121,7 @@ Optionally you can use the :class:`AsyncTask` class to instantiate a task and ke
     a.run()
 
     # wait indefinitely for the result and print it
+    # don't let the task return `None` or it will wait indefinitely
     print(a.result(wait=-1))
 
     # change the args
@@ -264,7 +265,7 @@ Reference
     Gets the result of a previously executed task
 
     :param str task_id: the uuid or name of the task
-    :param int wait: optional milliseconds to wait for a result. -1 for indefinite
+    :param int wait: optional milliseconds to wait for a result. -1 for indefinite, but be sure the result will not be `None` otherwise it will wait indefinitely!
     :param bool cached: run this against the cache backend.
     :returns: The result of the executed task