ORM (still!) neglects to use aliases it has set up when certain multiple subqueries are used AND multi table inheritance is in use

[ris]

This is following on from ticket #23605, which was successfully fixed but didn't fix our specific test case.

This turns out to be because our test case also used multi table inheritance.

So, details are basically the same as #23605, but using django 1.7.2 and the test models.py is:

from django.db import models

class ModelAParent ( models.Model ):
	pass

class ModelA ( ModelAParent ):
	pass

class ModelB ( models.Model ):
	modela_fk = models.ForeignKey ( ModelA )
	modelc_fk = models.ForeignKey ( "ModelC" )
	
	field_b0 = models.IntegerField ( null = True )
	field_b1 = models.BooleanField ()

class ModelC ( models.Model ):
	field_c0 = models.FloatField ()

The query is the same:

ModelA.objects.filter (
    Q ( pk__in = ModelA.objects.filter ( Q ( modelb__field_b0__gte = 1000000 / F ( "modelb__modelc_fk__field_c0" ) )
        & Q ( modelb__field_b1__exact = True )
        & ~Q ( modelb__pk__in = ModelB.objects.filter (
            ~(
                Q ( field_b1__exact = True )
                & Q ( field_b0__gte = 1000000 / F ( "modelc_fk__field_c0" ) )
             )
        ) )
    ).filter ( modelb__field_b1__exact = True )
) )

Used against postgres 9.1 generates the error:

ProgrammingError: invalid reference to FROM-clause entry for table "dummy_modelb"
LINE 1: ...") AND U0."field_b0" IS NOT NULL)) AND V1."id" = (dummy_mode...
                                                             ^
HINT:  Perhaps you meant to reference the table alias "v1".

[Anssi Kääriäinen]

This ticket was fixed by b68212f539f206679580afbfd008e7d329c9cd31. I'm adding a pull request for tests.

[Tim Graham <timograham@…>]

In 76ac07a9:

Refs #24090 -- Added a test for multi-table inheritance + subqueries.

Ticket #24090 was already fixed by
b68212f539f206679580afbfd008e7d329c9cd31, this commit adds tests to
verify this is indeed the case.

Thanks to Beauhurst for commissioning the work on this ticket.