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
27343	Different Chaining Of Qs+Filters behaves unexpectedly differently	Sven R. Kunze	nobody	"Hi Django-devs,

I couldn't find an explanation in the docs of the following behavior.

The variable my_q has the following definition (to get you the complete picture):

{{{
app_label, codename = perm.split('.')
user_q = Q(user_permissions__codename=codename, user_permissions__content_type__app_label=app_label)
group_q = Q(groups__permissions__codename=codename, groups__permissions__content_type__app_label=app_label)
my_q = Q(is_active=is_active) & (Q(is_superuser=is_superuser) | user_q | group_q)
}}}

We had issues with the following querysets:

{{{
User.objects.filter(my_q).filter(groups__in=[my_group]).distinct()  # works
User.objects.filter(my_q, groups__in=[my_group]).distinct()         # does not work
my_group.user_set.filter(my_q).distinct()                           # does not work
}}}

Those querysets actually try to get those users which have a certain permission and are in a specific group. We expected all three to be equivalent. However, the latter two yield superusers only.

Cheers,
Sven



Appendix - Related Queries

{{{
User.objects.filter(my_q).filter(groups__in=[my_group]).distinct().query  # works

'SELECT DISTINCT ""auth_user"".""id"", ""auth_user"".""password"", ""auth_user"".""last_login"", ""auth_user"".""is_superuser"", ""auth_user"".""username"", ""auth_user"".""first_name"", ""auth_user"".""last_name"", ""auth_user"".""email"", ""auth_user"".""is_staff"", ""auth_user"".""is_active"", ""auth_user"".""date_joined"" FROM ""auth_user"" LEFT OUTER JOIN ""auth_user_user_permissions"" ON (""auth_user"".""id"" = ""auth_user_user_permissions"".""user_id"") LEFT OUTER JOIN ""auth_permission"" ON (""auth_user_user_permissions"".""permission_id"" = ""auth_permission"".""id"") LEFT OUTER JOIN ""django_content_type"" ON (""auth_permission"".""content_type_id"" = ""django_content_type"".""id"") LEFT OUTER JOIN ""auth_user_groups"" ON (""auth_user"".""id"" = ""auth_user_groups"".""user_id"") LEFT OUTER JOIN ""auth_group"" ON (""auth_user_groups"".""group_id"" = ""auth_group"".""id"") LEFT OUTER JOIN ""auth_group_permissions"" ON (""auth_group"".""id"" = ""auth_group_permissions"".""group_id"") LEFT OUTER JOIN ""auth_permission"" T8 ON (""auth_group_permissions"".""permission_id"" = T8.""id"") LEFT OUTER JOIN ""django_content_type"" T9 ON (T8.""content_type_id"" = T9.""id"") INNER JOIN ""auth_user_groups"" T10 ON (""auth_user"".""id"" = T10.""user_id"") WHERE (""auth_user"".""is_active"" = True AND (""auth_user"".""is_superuser"" = True OR (""auth_permission"".""codename"" = 'permission_of_my_app' AND ""django_content_type"".""app_label"" = 'my_app') OR (T9.""app_label"" = 'my_app' AND T8.""codename"" = 'permission_of_my_app')) AND T10.""group_id"" IN (35))'

User.objects.filter(my_q, groups__in=[my_group]).distinct().query         # does not work

'SELECT DISTINCT ""auth_user"".""id"", ""auth_user"".""password"", ""auth_user"".""last_login"", ""auth_user"".""is_superuser"", ""auth_user"".""username"", ""auth_user"".""first_name"", ""auth_user"".""last_name"", ""auth_user"".""email"", ""auth_user"".""is_staff"", ""auth_user"".""is_active"", ""auth_user"".""date_joined"" FROM ""auth_user"" LEFT OUTER JOIN ""auth_user_user_permissions"" ON (""auth_user"".""id"" = ""auth_user_user_permissions"".""user_id"") LEFT OUTER JOIN ""auth_permission"" ON (""auth_user_user_permissions"".""permission_id"" = ""auth_permission"".""id"") LEFT OUTER JOIN ""django_content_type"" ON (""auth_permission"".""content_type_id"" = ""django_content_type"".""id"") INNER JOIN ""auth_user_groups"" ON (""auth_user"".""id"" = ""auth_user_groups"".""user_id"") INNER JOIN ""auth_group"" ON (""auth_user_groups"".""group_id"" = ""auth_group"".""id"") LEFT OUTER JOIN ""auth_group_permissions"" ON (""auth_group"".""id"" = ""auth_group_permissions"".""group_id"") LEFT OUTER JOIN ""auth_permission"" T8 ON (""auth_group_permissions"".""permission_id"" = T8.""id"") LEFT OUTER JOIN ""django_content_type"" T9 ON (T8.""content_type_id"" = T9.""id"") WHERE (""auth_user"".""is_active"" = True AND (""auth_user"".""is_superuser"" = True OR (""auth_permission"".""codename"" = 'permission_of_my_app' AND ""django_content_type"".""app_label"" = 'my_app') OR (T9.""app_label"" = 'my_app' AND T8.""codename"" = 'permission_of_my_app')) AND ""auth_user_groups"".""group_id"" IN (35))'

my_group.user_set.filter(my_q).distinct().query                           # does not work

'SELECT DISTINCT ""auth_user"".""id"", ""auth_user"".""password"", ""auth_user"".""last_login"", ""auth_user"".""is_superuser"", ""auth_user"".""username"", ""auth_user"".""first_name"", ""auth_user"".""last_name"", ""auth_user"".""email"", ""auth_user"".""is_staff"", ""auth_user"".""is_active"", ""auth_user"".""date_joined"" FROM ""auth_user"" INNER JOIN ""auth_user_groups"" ON (""auth_user"".""id"" = ""auth_user_groups"".""user_id"") INNER JOIN ""auth_group"" ON (""auth_user_groups"".""group_id"" = ""auth_group"".""id"") LEFT OUTER JOIN ""auth_user_user_permissions"" ON (""auth_user"".""id"" = ""auth_user_user_permissions"".""user_id"") LEFT OUTER JOIN ""auth_permission"" ON (""auth_user_user_permissions"".""permission_id"" = ""auth_permission"".""id"") LEFT OUTER JOIN ""django_content_type"" ON (""auth_permission"".""content_type_id"" = ""django_content_type"".""id"") LEFT OUTER JOIN ""auth_group_permissions"" ON (""auth_group"".""id"" = ""auth_group_permissions"".""group_id"") LEFT OUTER JOIN ""auth_permission"" T8 ON (""auth_group_permissions"".""permission_id"" = T8.""id"") LEFT OUTER JOIN ""django_content_type"" T9 ON (T8.""content_type_id"" = T9.""id"") WHERE (""auth_user_groups"".""group_id"" = 35 AND ""auth_user"".""is_active"" = True AND (""auth_user"".""is_superuser"" = True OR (""auth_permission"".""codename"" = 'permission_of_my_app' AND ""django_content_type"".""app_label"" = 'my_app') OR (T9.""app_label"" = 'my_app' AND T8.""codename"" = 'permission_of_my_app')))'
}}}"	Bug	closed	Database layer (models, ORM)	1.10	Normal	needsinfo			Unreviewed	0	0	0	0	0	0