This is from the current DateField? definition (django/core/meta/fields.py):
def pre_save(self, value, add):
if self.auto_now or (self.auto_now_add and add):
return datetime.datetime.now()
return value
When you modify an object that has this field using it's ChangeManipulator?, the field gets set to "null" from the request, because the DateTime? fields with auto_now_add=True or auto_now=True are not editable (line 387 of the same file).
An additional elif clause should be added to catch this problem, like this:
def pre_save(self, value, add):
if self.auto_now or (self.auto_now_add and add):
return datetime.datetime.now()
elif self.auto_now_add:
return the_current_value_from_the_db
else:
return value
I'm posting the ticket instead of a patch because I'm not sure how to get the current value from the DB from the field instance.
