Ensure empty label lists are disambiguated from None

PrefectHQ · Oct 14, 2020 · 3d06688 · 3d06688
1 parent 5f4f68f
commit 3d06688
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Showing 2 changed files with 5 additions and 1 deletion.
diff --git a/src/prefect_server/api/flows.py b/src/prefect_server/api/flows.py
@@ -545,7 +545,7 @@ async def schedule_flow_runs(flow_id: str, max_runs: int = None) -> List[str]:
 
         # if the event has parameter defaults or labels, we do allow for
         # same-time scheduling
-        if event.parameter_defaults or event.labels:
+        if event.parameter_defaults or event.labels is not None:
             md5 = hashlib.md5()
             param_string = str(sorted(json.dumps(event.parameter_defaults)))
             label_string = str(sorted(json.dumps(event.labels)))

diff --git a/tests/api/test_flows.py b/tests/api/test_flows.py
@@ -1142,6 +1142,10 @@ async def test_doesnt_schedule_same_time_twice(self, project_id):
             [dict(parameter_defaults=dict(x="a")), dict(labels=["b"])],
             [dict(labels=["c", "d"]), dict(labels=["c"])],
             [dict(labels=None), dict(labels=["ef"])],
+            [
+                dict(labels=None),
+                dict(labels=[]),
+            ],  # the scheduler should distinguish between none vs. empty
         ],
     )
     async def test_allows_for_same_time_if_event_attrs_are_different(