Testing if datetime is aware fails

manager.run(force)
  File "/var/www/hosts/bettersubbox.com/dev/local/lib/python2.7/site-packages/django_cron/__init__.py", line 209, in run
    with self.lock_class(cron_job_class, self.silent):
  File "/var/www/hosts/bettersubbox.com/dev/local/lib/python2.7/site-packages/django_cron/backends/lock/base.py", line 60, in __enter__
    raise self.LockFailedException(self.lock_failed_message())
  File "/var/www/hosts/bettersubbox.com/dev/local/lib/python2.7/site-packages/django_cron/backends/lock/cache.py", line 47, in lock_failed_message
    started = self.get_running_lock_date()
  File "/var/www/hosts/bettersubbox.com/dev/local/lib/python2.7/site-packages/django_cron/backends/lock/cache.py", line 90, in get_running_lock_date
    if not timezone.is_aware(date):
  File "/var/www/hosts/bettersubbox.com/dev/local/lib/python2.7/site-packages/django/utils/timezone.py", line 340, in is_aware
    return value.utcoffset() is not None
AttributeError: 'NoneType' object has no attribute 'utcoffset'
``

Django 1.9, failed once out of thousands of runs...

[maxim-kht]

Resolved in https://github.com/Tivix/django-cron/pull/130

[agronick]

Just one but they run all the time. I think the problem is that maybe 1 out of every 500 jobs finishes between the time when that cache key is checked and when it is read the second time.