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
21748	Invalid exclude result for related models	Sergey Tereschenko	nobody	"When making exclude query on fields added as reverse relations results are incorrect.
Here is an example:
models.py
{{{
class Author(models.Model):
    name = models.CharField(max_length=120)
    book = models.OneToOneField('Book', null=True, blank=True)

    def __unicode__(self):
        return self.name

class Reader(models.Model):
    name = models.CharField(max_length=120)
    book = models.OneToOneField('Book', null=True, blank=True)

    def __unicode__(self):
        return self.name

class Book(models.Model):
    name = models.CharField(max_length=120)

    def __unicode__(self):
        return self.name

class SimpleBook(models.Model):
    name = models.CharField(max_length=120)
    author = models.CharField(max_length=120, null=True, blank=True)
    reader = models.CharField(max_length=120, null=True, blank=True)

    def __unicode__(self):
        return ""%s"" % self.name  
}}}

Test data:
{{{
Book                    | Author        | Reader
The Lord of the Rings	| JRR Tolkien	| John
Pride and Prejudice	| Jane Austen	| x
His Dark Materials	| x     	| x
}}}

Correct query results (django 1.5):

One book without author and reader, two books, excluding books without author and reader.
{{{
In [2]: Book.objects.exclude(author=None, reader=None)
Out[2]: [<Book: The Lord of the Rings>, <Book: Pride and Prejudice>]

In [3]: Book.objects.filter(author=None, reader=None)
Out[3]: [<Book: His Dark Materials>]
}}}

Incorrect query results (django 1.6):
One book without without author and reader. If excluded - only one book is selected instead of two.
{{{
In [2]: Book.objects.exclude(author=None, reader=None)
Out[2]: [<Book: The Lord of the Rings>]

In [3]: Book.objects.filter(author=None, reader=None)
Out[3]: [<Book: His Dark Materials>]
}}}

Expected results: When exluding books without author and reader query must return 2 books. Just like it does with simple fields(which is not reverse relations), django 1.6:

{{{
In [2]: SimpleBook.objects.exclude(author=None, reader=None)
Out[2]: [<SimpleBook: The Lord of the Rings>, <SimpleBook: Pride and Prejudice>]

In [3]: SimpleBook.objects.filter(author=None, reader=None)
Out[3]: [<SimpleBook: His Dark Materials>]
}}}

"	Bug	closed	Database layer (models, ORM)	1.6	Normal	fixed			Ready for checkin	1	0	0	0	0	0