Remove support for timedelta for run_after

It's not obvious when the delta is evaluated, so could be a foot-gun

README.md

@@ -75,7 +75,7 @@ These attributes (besides `enqueue_on_commit`) can also be modified at run-time
 modified_task = calculate_meaning_of_life.using(priority=10)
 ```
 
-In addition to the above attributes, `run_after` can be passed to specify a specific time the task should run. Both a timezone-aware `datetime` or `timedelta` may be passed.
+In addition to the above attributes, `run_after` can be passed to specify a specific time the task should run.
 
 ### Enqueueing tasks
 

django_tasks/task.py

@@ -17,7 +17,6 @@
 
 from asgiref.sync import async_to_sync, sync_to_async
 from django.db.models.enums import TextChoices
-from django.utils import timezone
 from django.utils.translation import gettext_lazy as _
 from typing_extensions import ParamSpec, Self
 
@@ -110,10 +109,7 @@ def using(
         if queue_name is not None:
             changes["queue_name"] = queue_name
         if run_after is not None:
-            if isinstance(run_after, timedelta):
-                changes["run_after"] = timezone.now() + run_after
-            else:
-                changes["run_after"] = run_after
+            changes["run_after"] = run_after
         if backend is not None:
             changes["backend"] = backend
 

tests/tests/test_tasks.py

@@ -1,5 +1,5 @@
 import dataclasses
-from datetime import datetime, timedelta
+from datetime import datetime
 
 from django.test import SimpleTestCase, override_settings
 from django.utils import timezone
@@ -97,10 +97,6 @@ def test_using_run_after(self) -> None:
 
         self.assertIsNone(test_tasks.noop_task.run_after)
         self.assertEqual(test_tasks.noop_task.using(run_after=now).run_after, now)
-        self.assertIsInstance(
-            test_tasks.noop_task.using(run_after=timedelta(hours=1)).run_after,
-            datetime,
-        )
         self.assertIsNone(test_tasks.noop_task.run_after)
 
     def test_using_unknown_backend(self) -> None: