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
17972	regression: admin list_filter does not work with to_field	Karen Tracey	Julien Phalip	"This is #9994 exactly, recently reported as having re-appeared. Opening a new ticket rather than re-opening a 3-year-old fixed ticket. Given these models:

{{{
#!python
class Department(models.Model):
	code = models.CharField(max_length=4, unique=True)
	description = models.CharField(max_length=50, blank=True, null=True)

class Employee(models.Model):
	department = models.ForeignKey(Department, to_field=""code"")
	name = models.CharField(max_length=100)
}}}

And this admin definition:

{{{
#!python
class EmployeeAdmin(admin.ModelAdmin):
	list_display = ['name', 'department']
	list_filter = ['department']
}}}

Create a couple of departments (more than 1 needed to make the list filter show up), and an employee. Then on the employee list page, attempting to filter by a department fetches a url like:

http://localhost:8000/admin/ttt/employee/?department__id__exact=FINC

which results in an exception:

{{{
Environment:


Request Method: GET
Request URL: http://localhost:8000/admin/ttt/employee/?department__id__exact=FINC

Django Version: 1.4
Python Version: 2.7.2
Installed Applications:
('django.contrib.auth',
 'django.contrib.contenttypes',
 'django.contrib.sessions',
 'django.contrib.sites',
 'django.contrib.messages',
 'django.contrib.staticfiles',
 'django.contrib.admin',
 'ttt')
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',
 'ttt.middleware.TestMiddleware')


Traceback:
File ""C:\Users\kmtracey\django\trunk\django\core\handlers\base.py"" in get_response
  111.                         response = callback(request, *callback_args, **callback_kwargs)
File ""C:\Users\kmtracey\django\trunk\django\contrib\admin\options.py"" in wrapper
  366.                 return self.admin_site.admin_view(view)(*args, **kwargs)
File ""C:\Users\kmtracey\django\trunk\django\utils\decorators.py"" in _wrapped_view
  91.                     response = view_func(request, *args, **kwargs)
File ""C:\Users\kmtracey\django\trunk\django\views\decorators\cache.py"" in _wrapped_view_func
  89.         response = view_func(request, *args, **kwargs)
File ""C:\Users\kmtracey\django\trunk\django\contrib\admin\sites.py"" in inner
  196.             return view(request, *args, **kwargs)
File ""C:\Users\kmtracey\django\trunk\django\utils\decorators.py"" in _wrapper
  25.             return bound_func(*args, **kwargs)
File ""C:\Users\kmtracey\django\trunk\django\utils\decorators.py"" in _wrapped_view
  91.                     response = view_func(request, *args, **kwargs)
File ""C:\Users\kmtracey\django\trunk\django\utils\decorators.py"" in bound_func
  21.                 return func(self, *args2, **kwargs2)
File ""C:\Users\kmtracey\django\trunk\django\contrib\admin\options.py"" in changelist_view
  1128.                 self)
File ""C:\Users\kmtracey\django\trunk\django\contrib\admin\views\main.py"" in __init__
  71.         self.query_set = self.get_query_set(request)
File ""C:\Users\kmtracey\django\trunk\django\contrib\admin\views\main.py"" in get_query_set
  306.             new_qs = filter_spec.queryset(request, qs)
File ""C:\Users\kmtracey\django\trunk\django\contrib\admin\filters.py"" in queryset
  132.         return queryset.filter(**self.used_parameters)
File ""C:\Users\kmtracey\django\trunk\django\db\models\query.py"" in filter
  621.         return self._filter_or_exclude(False, *args, **kwargs)
File ""C:\Users\kmtracey\django\trunk\django\db\models\query.py"" in _filter_or_exclude
  639.             clone.query.add_q(Q(*args, **kwargs))
File ""C:\Users\kmtracey\django\trunk\django\db\models\sql\query.py"" in add_q
  1250.                             can_reuse=used_aliases, force_having=force_having)
File ""C:\Users\kmtracey\django\trunk\django\db\models\sql\query.py"" in add_filter
  1185.                 connector)
File ""C:\Users\kmtracey\django\trunk\django\db\models\sql\where.py"" in add
  69.             value = obj.prepare(lookup_type, value)
File ""C:\Users\kmtracey\django\trunk\django\db\models\sql\where.py"" in prepare
  320.             return self.field.get_prep_lookup(lookup_type, value)
File ""C:\Users\kmtracey\django\trunk\django\db\models\fields\__init__.py"" in get_prep_lookup
  310.             return self.get_prep_value(value)
File ""C:\Users\kmtracey\django\trunk\django\db\models\fields\__init__.py"" in get_prep_value
  537.         return int(value)

Exception Type: ValueError at /admin/ttt/employee/
Exception Value: invalid literal for int() with base 10: 'FINC'
}}}

#9994 had been fixed, unfortunately without tests. The above scenario works at r14673. The filtered URL differs from above, it is: 

http://localhost:8000/admin/ttt/employee/?department__code__exact=FINC

This correctly filters by department. r14674 introduces a regression, the list filter link href goes back to:

http://localhost:8000/admin/ttt/employee/?department__id__exact=FINC

Attempting to follow that link redirects to: 

http://localhost:8000/admin/ttt/employee/?e=1

So something subsequent to r14674 (which I have not tracked down) removes the admin's ""I'm confused error"" redirect and as a result we now get a server error for this case.

Furthermore attempting to manually ""correct"" the url to the version that would work results in:

{{{
Exception Type: SuspiciousOperation at /admin/ttt/employee/
Exception Value: Filtering by department__code__exact not allowed
}}}

So there may be more to fixing this than getting the list filter to generate the old url that did work."	Bug	closed	contrib.admin	dev	Release blocker	fixed			Accepted	0	0	0	0	0	0