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
26296	values() after extra() gives incorrect error message	aimestereo	aimestereo	"In documentation there's comment in `values()` section about some behavior of `extra`

https://docs.djangoproject.com/en/1.9/ref/models/querysets/#django.db.models.query.QuerySet.values

{{{
If you use a values() clause after an extra() call, any fields defined by a select argument in the extra() must be explicitly included in the values() call. Any extra() call made after a values() call will have its extra selected fields ignored.
}}}

It's points that any extra fields after values() call will be ignored. But I think that it's not correct and need more description.

For example it could be not obvious that next simple construction will cause exception and such an not obvious one!


{{{
User.objects.values('username').extra(select={'test_field': 1}).values('test_field', 'username')

FieldError: Cannot resolve keyword 'test_field' into field. Choices are: date_joined, email, first_name, groups, id, is_active, is_staff, is_superuser, last_login, last_name, logentry, password, test_field, user_permissions, username
}}}

I want to point out that `test_field` is listed in choices that's very confusing. It happens because of all checks is runs against `extra_select` but error is uses `extra` as part of available choices.


{{{
sorted(list(get_field_names_from_opts(opts)) + list(self.extra)
                               + list(self.annotation_select))
}}}

I can help you with this small change.
https://github.com/django/django/pull/6225"	Cleanup/optimization	closed	Database layer (models, ORM)	dev	Normal	wontfix			Accepted	1	0	1	0	1	0