id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
19364	Wrong exception raised at django/db/models/fields/related.py:343? (DoesNotExist instead of AttributeError)	lbragues@…		"My problem is at the admin models when calling a getattr from the save_module function using the object being saved, instead of returning the default value it raises a DoesNotExist exception, failing the python manual specification for getattr.
I'm wondering if the exception thrown shouldn't be AttributeError instead of DoesNotExist...
If I make a getattr call to that object and that exception is thrown my program will exit instead of being catched by the getattr method and the default value returned.

'''Reproducing:'''
''models.py''
{{{
class GroupProperty(models.Model):
	CHOICES = (
		('disk_quota','Disk Quota'),
		('n_backups','Number of Backups'),
	)
	group = models.ForeignKey(Group)
	key = models.CharField(max_length=200,choices=CHOICES)
	value = models.CharField(max_length=200)
	start = models.DateTimeField()
	end = models.DateTimeField()
	description = models.TextField()
	author = models.ForeignKey(User)
	edit = models.DateTimeField(default=datetime.now())
	creation = models.DateTimeField(default=datetime.now())

	# na alteracao actualiza data
	def save(self):
		self.edit = datetime.now()
		super(GroupProperty, self).save()

	class Meta:
		verbose_name_plural = ""Group Properties""
}}}

''admin.py''
{{{
class GroupPropertyAdmin(admin.ModelAdmin):
	fieldsets = [
		(None,               {'fields': ['group','key','value','start','end',""description""]}),
		('Auto generated fields', {'fields':['author','edit','creation']})
	]
	list_display = ('group', 'key','value','start','end')
	readonly_fields = ('edit','author','creation')
	list_filter = ['key','group']
	search_fields = ['key','value','group','description']
	ordering = ('-creation',)

	def save_model(self, request, obj, form, change): 
		#Error here
		if getattr(obj, 'author', 'None') is 'None':
			obj.author = request.user
		obj.save()

admin.site.register(GroupProperty, GroupPropertyAdmin)
}}}

'''Django stacktrace:'''

{{{
Environment:


Request Method: POST
Request URL: http://localhost:8080/admin/core/groupproperty/add/

Django Version: 1.4.2
Python Version: 2.7.3
Installed Applications:
('django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.sites',
 'django.contrib.messages',
 'django.contrib.staticfiles',
 'django.contrib.admin',
 '*****.core')
Installed Middleware:
('django.middleware.common.CommonMiddleware',
 'django.contrib.sessions.middleware.SessionMiddleware',
 'django.middleware.csrf.CsrfViewMiddleware',
 'django.contrib.auth.middleware.AuthenticationMiddleware',
 'django.contrib.messages.middleware.MessageMiddleware')


Traceback:
File ""/usr/local/lib/python2.7/dist-packages/Django-1.4.2-py2.7.egg/django/core/handlers/base.py"" in get_response
  111.                         response = callback(request, *callback_args, **callback_kwargs)
File ""/usr/local/lib/python2.7/dist-packages/Django-1.4.2-py2.7.egg/django/contrib/admin/options.py"" in wrapper
  366.                 return self.admin_site.admin_view(view)(*args, **kwargs)
File ""/usr/local/lib/python2.7/dist-packages/Django-1.4.2-py2.7.egg/django/utils/decorators.py"" in _wrapped_view
  91.                     response = view_func(request, *args, **kwargs)
File ""/usr/local/lib/python2.7/dist-packages/Django-1.4.2-py2.7.egg/django/views/decorators/cache.py"" in _wrapped_view_func
  89.         response = view_func(request, *args, **kwargs)
File ""/usr/local/lib/python2.7/dist-packages/Django-1.4.2-py2.7.egg/django/contrib/admin/sites.py"" in inner
  196.             return view(request, *args, **kwargs)
File ""/usr/local/lib/python2.7/dist-packages/Django-1.4.2-py2.7.egg/django/utils/decorators.py"" in _wrapper
  25.             return bound_func(*args, **kwargs)
File ""/usr/local/lib/python2.7/dist-packages/Django-1.4.2-py2.7.egg/django/utils/decorators.py"" in _wrapped_view
  91.                     response = view_func(request, *args, **kwargs)
File ""/usr/local/lib/python2.7/dist-packages/Django-1.4.2-py2.7.egg/django/utils/decorators.py"" in bound_func
  21.                 return func(self, *args2, **kwargs2)
File ""/usr/local/lib/python2.7/dist-packages/Django-1.4.2-py2.7.egg/django/db/transaction.py"" in inner
  209.                 return func(*args, **kwargs)
File ""/usr/local/lib/python2.7/dist-packages/Django-1.4.2-py2.7.egg/django/contrib/admin/options.py"" in add_view
  955.                 self.save_model(request, new_object, form, False)
File ""/home/someone/folder/to/project/****/core/admin.py"" in save_model
  36. 		if getattr(obj, 'author', 'None') is 'None':
File ""/usr/local/lib/python2.7/dist-packages/Django-1.4.2-py2.7.egg/django/db/models/fields/related.py"" in __get__
  343.                 raise self.field.rel.to.DoesNotExist

Exception Type: DoesNotExist at /admin/core/groupproperty/add/
Exception Value:
}}}
 "	Bug	closed	Documentation	1.4	Normal	invalid	DoesNotExist, django.db, getattr,	lbragues	Accepted	0	0	0	0	0	0