* Model init no longer performs a database query to refetch the related objects it is passed.
* Model init now caches unsaved related objects correctly, too. (Previously, accessing the field would raise `DoesNotExist` error for `null=False` fields.)
* Added tests for assigning `None` to `null=True` `ForeignKey` fields (refs #6886).
git-svn-id: http://code.djangoproject.com/svn/django/trunk@8185 bcc190cf-cafb-0310-a4f2-bffc1f526a37
* Raise a ValueError if you try to assign the wrong type of object.
* Raise a ValueError if you try to assign None to a field not specified with null=True.
* Cache the set value at set time instead of just at lookup time.
This is a slightly backwards-incompatible change; see BackwardsIncompatibleChanges for more details.
git-svn-id: http://code.djangoproject.com/svn/django/trunk@7574 bcc190cf-cafb-0310-a4f2-bffc1f526a37
