Consider server timezone on _get_timezone_offset instead of django's settings (#886)

* Scheduler shouldnt ignore specific times on crontab

* Use aware_now to get server's timezone rather than using django's

* Update schedulers.py

* Update schedulers.py

* Update schedulers.py

* Update django_celery_beat/schedulers.py

* adding tests

---------

Co-authored-by: Asif Saif Uddin <auvipy@gmail.com>

Author: iwalucas

django_celery_beat/schedulers.py

@@ -19,7 +19,6 @@
 from django.db.models import Case, F, IntegerField, Q, When
 from django.db.models.functions import Cast
 from django.db.utils import DatabaseError, InterfaceError
-from django.utils import timezone
 from kombu.utils.encoding import safe_repr, safe_str
 from kombu.utils.json import dumps, loads
 
@@ -364,7 +363,9 @@ def _get_timezone_offset(self, timezone_name):
             int: The hour offset
         """
         # Get server timezone
-        server_tz = timezone.get_current_timezone()
+        server_time = aware_now()
+        # Use server_time.tzinfo directly if it is already a ZoneInfo instance
+        server_tz = server_time.tzinfo if isinstance(server_time.tzinfo, ZoneInfo) else ZoneInfo(str(server_time.tzinfo))
 
         if isinstance(timezone_name, ZoneInfo):
             timezone_name = timezone_name.key

t/unit/test_schedulers.py

@@ -1453,3 +1453,55 @@ def mock_apply_async(*args, **kwargs):
         ma.run_tasks(self.request, PeriodicTask.objects.filter(id=self.m1.id))
         assert 'periodic_task_name' in self.captured_headers
         assert self.captured_headers['periodic_task_name'] == self.m1.name
+
+
+
+@pytest.mark.django_db
+class test_timezone_offset_handling:
+    def setup_method(self):
+        self.app = patch("django_celery_beat.schedulers.current_app").start()
+
+    def teardown_method(self):
+        patch.stopall()
+
+    @patch("django_celery_beat.schedulers.aware_now")
+    def test_server_timezone_handling_with_zoneinfo(self, mock_aware_now):
+        """Test handling when server timezone is already a ZoneInfo instance."""
+
+        # Create a mock scheduler with only the methods we need to test
+        class MockScheduler:
+            _get_timezone_offset = schedulers.DatabaseScheduler._get_timezone_offset
+
+        s = MockScheduler()
+
+        tokyo_tz = ZoneInfo("Asia/Tokyo")
+        mock_now = datetime(2023, 1, 1, 12, 0, 0, tzinfo=tokyo_tz)
+        mock_aware_now.return_value = mock_now
+
+        # Test with a different timezone
+        new_york_tz = "America/New_York"
+        offset = s._get_timezone_offset(new_york_tz)  # Pass self explicitly
+
+        # Tokyo is UTC+9, New York is UTC-5, so difference should be 14 hours
+        assert offset == 14
+        assert mock_aware_now.called
+
+    @patch("django_celery_beat.schedulers.aware_now")
+    def test_timezone_offset_with_zoneinfo_object_param(self, mock_aware_now):
+        """Test handling when timezone_name parameter is a ZoneInfo object."""
+
+        class MockScheduler:
+            _get_timezone_offset = schedulers.DatabaseScheduler._get_timezone_offset
+
+        s = MockScheduler()
+
+        tokyo_tz = ZoneInfo("Asia/Tokyo")
+        mock_now = datetime(2023, 1, 1, 12, 0, 0, tzinfo=tokyo_tz)
+        mock_aware_now.return_value = mock_now
+
+        # Test with a ZoneInfo object as parameter
+        new_york_tz = ZoneInfo("America/New_York")
+        offset = s._get_timezone_offset(new_york_tz)  # Pass self explicitly
+
+        # Tokyo is UTC+9, New York is UTC-5, so difference should be 14 hours
+        assert offset == 14