Cannot add new tasks in Django admin: '>=' not supported between instances of 'NoneType' and 'datetime.datetime'

[danjac]

Describe the bug

Trying to add a new task via Django admin, I get this error:

TypeError at /admin/scheduler/task/add/

'>=' not supported between instances of 'NoneType' and 'datetime.datetime'

To Reproduce
Steps to reproduce the behavior:

1. Go to /admin/scheduler/task/add/
2. Set Task type to Repeatable, every 6 minutes, default queue
3. Click save

Expected behavior
A clear and concise description of what you expected to happen.

New task is saved to database

Screenshots
If applicable, add screenshots to help explain your problem.

Desktop (please complete the following information):

• OS: Fedora
• python version: 3.13
• django version: 5.2.3
• django-tasks-scheduler >= 4.0.4

Additional context
Add any other context about the problem here.

Environment:


Request Method: POST
Request URL: http://localhost:8000/admin/scheduler/task/add/

Django Version: 5.2.3
Python Version: 3.13.3
Installed Applications:
['django.contrib.admin',
 'django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.humanize',
 'django.contrib.messages',
 'django.contrib.postgres',
 'django.contrib.sessions',
 'django.contrib.sitemaps',
 'django.contrib.sites',
 'django.contrib.staticfiles',
 'django.forms',
 'allauth',
 'allauth.account',
 'allauth.socialaccount',
 'allauth.socialaccount.providers.google',
 'csp',
 'django_htmx',
 'django_linear_migrations',
 'django_tailwind_cli',
 'django_typer',
 'django_version_checks',
 'health_check',
 'health_check.db',
 'health_check.cache',
 'health_check.contrib.migrations',
 'health_check.contrib.psutil',
 'health_check.contrib.redis',
 'heroicons',
 'scheduler',
 'template_partials',
 'widget_tweaks',
 'radiofeed.episodes',
 'radiofeed.feedparser',
 'radiofeed.podcasts',
 'radiofeed.users',
 'whitenoise.runserver_nostatic',
 'django_browser_reload',
 'debug_toolbar']
Installed Middleware:
['django.middleware.security.SecurityMiddleware',
 'whitenoise.middleware.WhiteNoiseMiddleware',
 'django_permissions_policy.PermissionsPolicyMiddleware',
 'django.contrib.sites.middleware.CurrentSiteMiddleware',
 'django.contrib.sessions.middleware.SessionMiddleware',
 'django.middleware.csrf.CsrfViewMiddleware',
 'django.middleware.locale.LocaleMiddleware',
 'django.contrib.messages.middleware.MessageMiddleware',
 'django.contrib.auth.middleware.AuthenticationMiddleware',
 'django.middleware.common.CommonMiddleware',
 'django.middleware.gzip.GZipMiddleware',
 'django.middleware.clickjacking.XFrameOptionsMiddleware',
 'allauth.account.middleware.AccountMiddleware',
 'django_htmx.middleware.HtmxMiddleware',
 'csp.middleware.CSPMiddleware',
 'radiofeed.middleware.HtmxCacheMiddleware',
 'radiofeed.middleware.HtmxMessagesMiddleware',
 'radiofeed.middleware.HtmxRedirectMiddleware',
 'radiofeed.middleware.SearchMiddleware',
 'radiofeed.episodes.middleware.PlayerMiddleware',
 'django_browser_reload.middleware.BrowserReloadMiddleware',
 'debug_toolbar.middleware.DebugToolbarMiddleware']



Traceback (most recent call last):
  File "/home/danjac/Projects/radiofeed-app/.venv/lib64/python3.13/site-packages/django/core/handlers/exception.py", line 55, in inner
    response = get_response(request)
               ^^^^^^^^^^^^^^^^^^^^^
  File "/home/danjac/Projects/radiofeed-app/.venv/lib64/python3.13/site-packages/django/core/handlers/base.py", line 197, in _get_response
    response = wrapped_callback(request, *callback_args, **callback_kwargs)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/danjac/Projects/radiofeed-app/.venv/lib64/python3.13/site-packages/django/contrib/admin/options.py", line 719, in wrapper
    return self.admin_site.admin_view(view)(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/danjac/Projects/radiofeed-app/.venv/lib64/python3.13/site-packages/django/utils/decorators.py", line 192, in _view_wrapper
    result = _process_exception(request, e)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/danjac/Projects/radiofeed-app/.venv/lib64/python3.13/site-packages/django/utils/decorators.py", line 190, in _view_wrapper
    response = view_func(request, *args, **kwargs)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/danjac/Projects/radiofeed-app/.venv/lib64/python3.13/site-packages/django/views/decorators/cache.py", line 80, in _view_wrapper
    response = view_func(request, *args, **kwargs)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/danjac/Projects/radiofeed-app/.venv/lib64/python3.13/site-packages/django/contrib/admin/sites.py", line 246, in inner
    return view(request, *args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/danjac/Projects/radiofeed-app/.venv/lib64/python3.13/site-packages/django/contrib/admin/options.py", line 1984, in add_view
    return self.changeform_view(request, None, form_url, extra_context)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/danjac/Projects/radiofeed-app/.venv/lib64/python3.13/site-packages/django/utils/decorators.py", line 48, in _wrapper
    return bound_method(*args, **kwargs)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/danjac/Projects/radiofeed-app/.venv/lib64/python3.13/site-packages/django/utils/decorators.py", line 192, in _view_wrapper
    result = _process_exception(request, e)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/danjac/Projects/radiofeed-app/.venv/lib64/python3.13/site-packages/django/utils/decorators.py", line 190, in _view_wrapper
    response = view_func(request, *args, **kwargs)
               ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/danjac/Projects/radiofeed-app/.venv/lib64/python3.13/site-packages/django/contrib/admin/options.py", line 1843, in changeform_view
    return self._changeform_view(request, object_id, form_url, extra_context)
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/danjac/Projects/radiofeed-app/.venv/lib64/python3.13/site-packages/django/contrib/admin/options.py", line 1894, in _changeform_view
    self.save_model(request, new_object, form, not add)
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/home/danjac/Projects/radiofeed-app/.venv/lib64/python3.13/site-packages/django/contrib/admin/options.py", line 1314, in save_model
    obj.save()
    ^^^^^^^^^^
  File "/home/danjac/Projects/radiofeed-app/.venv/lib64/python3.13/site-packages/scheduler/models/task.py", line 369, in save
    self._schedule()
    ^^^^^^^^^^^^^^^^
  File "/home/danjac/Projects/radiofeed-app/.venv/lib64/python3.13/site-packages/scheduler/models/task.py", line 348, in _schedule
    schedule_time = self._schedule_time()
                    ^^^^^^^^^^^^^^^^^^^^^
  File "/home/danjac/Projects/radiofeed-app/.venv/lib64/python3.13/site-packages/scheduler/models/task.py", line 277, in _schedule_time
    if self.scheduled_time >= _now:
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^

Exception Type: TypeError at /admin/scheduler/task/add/
Exception Value: '>=' not supported between instances of 'NoneType' and 'datetime.datetime'

[danjac]

Looking at the code it's obvious this will always break if the scheduled_time is not set: https://github.com/django-commons/django-tasks-scheduler/blob/master/scheduler/models/task.py#L277

        elif self.task_type == TaskType.REPEATABLE:
            _now = timezone.now()
            if self.scheduled_time >= _now:
                return utc(self.scheduled_time) if django_settings.USE_TZ else self.scheduled_time

[VigNalla]

TypeError: '>=' not supported between instances of 'NoneType' and 'datetime.datetime'

occurs because scheduled_time can be None, but the _schedule_time() method compares it directly with datetime.now() using:

if self.scheduled_time >= _now:

This comparison throws a TypeError if scheduled_time is None.

While creating a Repeatable Task via the Django admin page, there is currently no input field for scheduled_time, which means it is always None during task creation.

So, when _schedule_time() is called during save(), and the line if self.scheduled_time >= _now runs, it fails because of that None value.

Suggested Fix

Option 1:

Add a check for None before the comparison. For example:

if not self.scheduled_time:
    self.scheduled_time = timezone.now()

Option 2:

Add the default value to the model field

scheduled_time = models.DateTimeField(_("scheduled time"), blank=True, null=True, default=timezone.now())

[danjac]

scheduled_time = models.DateTimeField(_("scheduled time"), blank=True, null=True, default=timezone.now())

default should be timezone.now not timezone.now() (or just use auto_now_add=True). However making it default might not be what you want if you rely on the job being triggered some time in the future. I'd just rewrite this:

        elif self.task_type == TaskType.REPEATABLE:
            now = timezone.now()
            scheduled_time = self.scheduled_time or now
            if scheduled_time >= now:
                return utc(scheduled_time) if django_settings.USE_TZ else scheduled_time