Merge pull request #3494 from PrefectHQ/label-update

Allow for None as labels attribute of clocks

src/prefect/schedules/clocks.py

@@ -19,7 +19,7 @@ def __init__(
     ) -> None:
         self.start_time = start_time
         self.parameter_defaults = parameter_defaults or dict()
-        self.labels = labels or []
+        self.labels = labels
 
     def __eq__(self, other: Any) -> bool:
         if not isinstance(other, (ClockEvent, datetime)):
@@ -82,7 +82,7 @@ def __init__(
         self.start_date = start_date
         self.end_date = end_date
         self.parameter_defaults = parameter_defaults or dict()
-        self.labels = labels or []
+        self.labels = labels
 
     def events(self, after: datetime = None) -> Iterable[ClockEvent]:
         """

tests/schedules/test_clocks.py

@@ -33,15 +33,15 @@ def test_clock_event_requires_start_time(self):
 
         assert e.start_time == now
         assert e.parameter_defaults == dict()
-        assert e.labels == []
+        assert e.labels is None
 
     def test_clock_event_accepts_parameters(self):
         now = pendulum.now("UTC")
         e = clocks.ClockEvent(now, parameter_defaults=dict(x=42, z=[1, 2, 3]))
 
         assert e.start_time == now
         assert e.parameter_defaults == dict(x=42, z=[1, 2, 3])
-        assert e.labels == []
+        assert e.labels is None
 
     def test_clock_event_accepts_labels(self):
         now = pendulum.now("UTC")
@@ -117,7 +117,7 @@ def test_create_interval_clock(self):
             start_date=pendulum.now("UTC"), interval=timedelta(days=1)
         )
         assert c.parameter_defaults == dict()
-        assert c.labels == []
+        assert c.labels is None
 
     def test_create_interval_clock_with_parameters(self):
         c = clocks.IntervalClock(
@@ -145,7 +145,7 @@ def test_start_date_can_be_none(self):
         assert c.interval == timedelta(hours=1)
         assert c.end_date is None
         assert c.parameter_defaults == dict()
-        assert c.labels == []
+        assert c.labels is None
 
     def test_end_date(self):
         c = clocks.IntervalClock(
@@ -155,7 +155,7 @@ def test_end_date(self):
         assert c.interval == timedelta(hours=1)
         assert c.end_date == pendulum.datetime(2020, 1, 1)
         assert c.parameter_defaults == dict()
-        assert c.labels == []
+        assert c.labels is None
 
     def test_interval_clock_interval_must_be_positive(self):
         with pytest.raises(ValueError, match="greater than 0"):
@@ -384,7 +384,7 @@ class TestCronClock:
     def test_create_cron_clock(self):
         c = clocks.CronClock("* * * * *")
         assert c.parameter_defaults == dict()
-        assert c.labels == []
+        assert c.labels is None
 
     def test_create_cron_clock_with_parameters(self):
         c = clocks.CronClock("* * * * *", parameter_defaults=dict(x=42))
@@ -625,15 +625,15 @@ def test_create_dates_clock_one_date(self):
         clock = clocks.DatesClock(dates=[now])
         assert clock.start_date == clock.end_date == now
         assert clock.parameter_defaults == dict()
-        assert clock.labels == []
+        assert clock.labels is None
 
     def test_create_dates_clock_multiple_dates(self):
         now = pendulum.now("UTC")
         clock = clocks.DatesClock(dates=[now.add(days=1), now.add(days=2), now])
         assert clock.start_date == now
         assert clock.end_date == now.add(days=2)
         assert clock.parameter_defaults == dict()
-        assert clock.labels == []
+        assert clock.labels is None
 
     def test_create_dates_clock_multiple_dates_with_parameters(self):
         now = pendulum.now("UTC")

tests/serialization/test_schedules.py

@@ -37,6 +37,7 @@ def test_serialize_schedule_with_parameters():
 
     output = s2.next(3, after=dt, return_events=True)
 
+    assert all([e.labels is None for e in output])
     assert all([isinstance(e, clocks.ClockEvent) for e in output])