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
29727	Lookup using F() on a non-existing model field doesn't throw an error	Vidya Rani D G	Alexander Holmbäck	"Fetching the value of a non-existing field on a model using F() object does not throw an error. 

Instead, it is just giving the FK value of the instance. 

Please find below a minimal test case to reproduce this issue. 

{{{
#!python

# lineitem/models.py 

from django.db import models


class Account(models.Model):
    REGULAR = 'R'
    GOLD = 'G'
    PLATINUM = 'P'
    ACCOUNT_TYPE_CHOICES = (
        (REGULAR, 'Regular'),
        (GOLD, 'Gold'),
        (PLATINUM, 'Platinum'),
    )

    account_type = models.CharField(
        max_length=1,
        choices=ACCOUNT_TYPE_CHOICES,
        default=REGULAR,
    )


class Client(models.Model):
    name = models.CharField(max_length=50)
    registered_on = models.DateField()
    account_type = models.ForeignKey(Account, on_delete=models.CASCADE)

$ python manage.py shell

In [1]: from datetime import date, timedelta

In [2]: from models import Client, Account

In [3]: Client.objects.create(
   ...:     name='Jane Doe',
   ...:     account_type=Account.objects.create(account_type=Account.REGULAR),
   ...:     registered_on=date.today() - timedelta(days=36)
   ...: )
   ...: Client.objects.create(
   ...:     name='James Smith',
   ...:     account_type=Account.objects.create(account_type=Account.GOLD),
   ...:     registered_on=date.today() - timedelta(days=5)
   ...: )
   ...: Client.objects.create(
   ...:     name='Jack Black',
   ...:     account_type=Account.objects.create(account_type=Account.PLATINUM),
   ...:     registered_on=date.today() - timedelta(days=10 * 365)
   ...: )
   ...: 
   ...: 
Out[3]: <Client: Client object (6)>

In [4]: from django.db.models import F

In [5]: Client.objects.values(client_name=F('name'), account_name=F('account_type__name'))

Out[5]: <QuerySet [{'client_name': 'Jane Doe', 'account_name': 2}, {'client_name': 'James Smith', 'account_name': 3}, {'client_name': 'Jack Black', 'account_name': 4}, {'client_name': 'Jane Doe', 'account_name': 5}, {'client_name': 'James Smith', 'account_name': 6}, {'client_name': 'Jack Black', 'account_name': 7}]>

In [6]: print(queryset.query)
SELECT ""lineitem_client"".""name"" AS ""client_name"", ""lineitem_client"".""account_type_id"" AS ""account_name"" FROM ""lineitem_client""

}}}"	Bug	closed	Database layer (models, ORM)	2.1	Release blocker	fixed	F() expressions	Mariusz Felisiak	Ready for checkin	1	0	0	0	0	0