Fixed time zone issue and added a test case

Author: JinRiYao2001

django_celery_beat/models.py

@@ -390,15 +390,10 @@ def from_schedule(cls, schedule):
         except MultipleObjectsReturned:
             return cls.objects.filter(**spec).first()
 
-    def due_start_time(self, start_time):
+    def due_start_time(self, start_time, tz):
+        if str(start_time.tzinfo) != str(tz):
+            start_time = start_time.astimezone(tz)
         start, ends_in, now = self.schedule.remaining_delta(start_time)
-
-        same_tz = str(start.tzinfo) == str(now.tzinfo)
-        different_offset = now.utcoffset() != start.utcoffset()
-
-        if same_tz and different_offset:
-            start = start.replace(tzinfo=now.tzinfo)
-
         return start + ends_in
 
 
@@ -675,9 +670,8 @@ def scheduler(self):
     def schedule(self):
         return self.scheduler.schedule
 
-    @property
-    def due_start_time(self):
+    def due_start_time(self, tz):
         if self.crontab:
-            return self.crontab.due_start_time(self.start_time)
+            return self.crontab.due_start_time(self.start_time, tz)
         else:
             return self.start_time

django_celery_beat/schedulers.py

@@ -116,8 +116,9 @@ def is_due(self):
             if now < self.model.start_time:
                 # The datetime is before the start date - don't run.
                 # send a delay to retry on start_time
+                now_tz = now.tzinfo
                 delay = math.ceil(
-                    (self.model.due_start_time - now).total_seconds()
+                    (self.model.due_start_time(now_tz) - now).total_seconds()
                 )
 
                 return schedules.schedstate(False, delay)

requirements/test.txt

@@ -2,3 +2,4 @@ pytest-django>=4.5.2,<5.0
 pytest>=6.2.5,<9.0
 pytest-timeout
 ephem
+pytz

t/unit/test_schedulers.py

@@ -6,6 +6,7 @@
 from time import monotonic
 
 import pytest
+import pytz
 from celery.schedules import crontab, schedule, solar
 from django.contrib.admin.sites import AdminSite
 from django.contrib.messages.storage.fallback import FallbackStorage
@@ -821,6 +822,53 @@ def test_crontab_with_start_time_after_crontab(self, app):
         assert not is_due
         assert next_check == pytest.approx(expected_delay, abs=60)
 
+    def test_crontab_with_start_time_different_time_zone(self, app):
+        now = app.now()
+
+        delay_minutes = 2
+
+        test_start_time = now + timedelta(minutes=delay_minutes)
+
+        crontab_time = test_start_time + timedelta(minutes=delay_minutes)
+
+        tz = pytz.timezone('Asia/Shanghai')
+        test_start_time = test_start_time.astimezone(tz)
+
+        task = self.create_model_crontab(
+            crontab(minute=f'{crontab_time.minute}'),
+            start_time=test_start_time)
+
+        entry = EntryTrackSave(task, app=app)
+
+        is_due, next_check = entry.is_due()
+
+        expected_delay = 2 * delay_minutes * 60
+
+        assert not is_due
+        assert next_check == pytest.approx(expected_delay, abs=60)
+
+        now = app.now()
+
+        crontab_time = now + timedelta(minutes=delay_minutes)
+
+        test_start_time = crontab_time + timedelta(minutes=delay_minutes)
+
+        tz = pytz.timezone('Asia/Shanghai')
+        test_start_time = test_start_time.astimezone(tz)
+
+        task = self.create_model_crontab(
+            crontab(minute=f'{crontab_time.minute}'),
+            start_time=test_start_time)
+
+        entry = EntryTrackSave(task, app=app)
+
+        is_due, next_check = entry.is_due()
+
+        expected_delay = delay_minutes * 60 + 3600
+
+        assert not is_due
+        assert next_check == pytest.approx(expected_delay, abs=60)
+
     def test_crontab_with_start_time_tick(self, app):
         PeriodicTask.objects.all().delete()
         s = self.Scheduler(app=self.app)