fix(tasks) Fix crontab schedules triggering with no last_run

src/sentry/taskworker/scheduler/schedules.py

@@ -124,7 +124,7 @@ def monitor_value(self) -> str:
     def is_due(self, last_run: datetime | None = None) -> bool:
         """Check if the schedule is due to run again based on last_run."""
         if last_run is None:
-            return True
+            last_run = timezone.now() - timedelta(minutes=1)
         remaining = self.remaining_seconds(last_run)
         return remaining <= 0
 
@@ -135,7 +135,7 @@ def remaining_seconds(self, last_run: datetime | None = None) -> int:
         Use the current time to find the next schedule time
         """
         if last_run is None:
-            return 0
+            last_run = timezone.now() - timedelta(minutes=1)
 
         # This could result in missed beats, or increased load on redis.
         last_run = last_run.replace(second=0, microsecond=0)

tests/sentry/taskworker/scheduler/test_runner.py

@@ -377,42 +377,40 @@ def test_schedulerunner_tick_fast_and_slow(
             assert sleep_time == 30
 
         called = extract_sent_tasks(mock_send)
-        assert called == ["second", "valid"]
+        assert called == ["valid"]
 
         run_storage.delete("test:valid")
         with freeze_time("2025-01-24 14:25:30"):
             sleep_time = schedule_set.tick()
             assert sleep_time == 30
 
         called = extract_sent_tasks(mock_send)
-        assert called == ["second", "valid", "valid"]
+        assert called == ["valid", "valid"]
 
         run_storage.delete("test:valid")
-        run_storage.delete("test:second")
-        with freeze_time("2025-01-24 14:26:01"):
+        with freeze_time("2025-01-24 14:26:00"):
             sleep_time = schedule_set.tick()
             assert sleep_time == 30
 
         called = extract_sent_tasks(mock_send)
-        assert called == ["second", "valid", "valid", "second", "valid"]
+        assert called == ["valid", "valid", "second", "valid"]
 
         run_storage.delete("test:valid")
-        with freeze_time("2025-01-24 14:26:31"):
+        with freeze_time("2025-01-24 14:26:30"):
             sleep_time = schedule_set.tick()
             assert sleep_time == 30
 
         called = extract_sent_tasks(mock_send)
-        assert called == ["second", "valid", "valid", "second", "valid", "valid"]
+        assert called == ["valid", "valid", "second", "valid", "valid"]
 
         run_storage.delete("test:valid")
-        with freeze_time("2025-01-24 14:27:01"):
+        with freeze_time("2025-01-24 14:27:00"):
             sleep_time = schedule_set.tick()
             assert sleep_time == 30
 
         assert run_storage.read("test:valid")
         called = extract_sent_tasks(mock_send)
         assert called == [
-            "second",
             "valid",
             "valid",
             "second",

tests/sentry/taskworker/scheduler/test_schedules.py

@@ -80,6 +80,12 @@ def test_crontabschedule_invalid() -> None:
 def test_crontabschedule_is_due() -> None:
     schedule = CrontabSchedule("test", crontab(minute="*/5"))
 
+    # no last_run and not time to spawn
+    with freeze_time("2025-01-24 14:23:00"):
+        now = timezone.now()
+        assert not schedule.is_due(None)
+        assert not schedule.is_due(now)
+
     with freeze_time("2025-01-24 14:25:00"):
         now = timezone.now()
         assert schedule.is_due(None)
@@ -109,7 +115,15 @@ def test_crontabschedule_is_due() -> None:
 def test_crontabschedule_remaining_seconds() -> None:
     schedule = CrontabSchedule("test", crontab(minute="*/5"))
 
-    assert schedule.remaining_seconds(None) == 0
+    # no last_run, but due in one minute
+    with freeze_time("2025-01-24 14:24:00"):
+        assert not schedule.is_due(None)
+        assert schedule.remaining_seconds(None) == 60
+
+    # no last_run, but due now
+    with freeze_time("2025-01-24 14:25:00"):
+        assert schedule.is_due(None)
+        assert schedule.remaining_seconds(None) == 0
 
     # last run was late (14:21), next spawn is at 14:25
     with freeze_time("2025-01-24 14:25:00"):