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
20250	AttributeError when filtering annotated queryset with negated Q (via fk)	jan.koutny@…	Tim Graham <timograham@…>	"If these conditions are met:
* annotated queryset
* Q is filtering attribute related via foreign key
* Q is negation

Then {{{AttributeError: 'NoneType' object has no attribute 'startswith'}}} exception is throwed. Stack looks the same as in 12687 (fixed), see below.

Note that *all* conditions above are necessary, code works if one omitted. Reproducible with Django 1.4.5, python 2.6.8.

{{{
Traceback (most recent call last):
  File ""bug.py"", line 16, in <module>
    print qst.query
  File ""/usr/lib/python2.6/site-packages/django/db/models/sql/query.py"", line 167, in __str__
    sql, params = self.sql_with_params()
  File ""/usr/lib/python2.6/site-packages/django/db/models/sql/query.py"", line 175, in sql_with_params
    return self.get_compiler(DEFAULT_DB_ALIAS).as_sql()
  File ""/usr/lib/python2.6/site-packages/django/db/models/sql/compiler.py"", line 82, in as_sql
    where, w_params = self.query.where.as_sql(qn=qn, connection=self.connection)
  File ""/usr/lib/python2.6/site-packages/django/db/models/sql/where.py"", line 91, in as_sql
    sql, params = child.as_sql(qn=qn, connection=connection)
  File ""/usr/lib/python2.6/site-packages/django/db/models/sql/where.py"", line 91, in as_sql
    sql, params = child.as_sql(qn=qn, connection=connection)
  File ""/usr/lib/python2.6/site-packages/django/db/models/sql/where.py"", line 91, in as_sql
    sql, params = child.as_sql(qn=qn, connection=connection)
  File ""/usr/lib/python2.6/site-packages/django/db/models/sql/where.py"", line 91, in as_sql
    sql, params = child.as_sql(qn=qn, connection=connection)
  File ""/usr/lib/python2.6/site-packages/django/db/models/sql/where.py"", line 91, in as_sql
    sql, params = child.as_sql(qn=qn, connection=connection)
  File ""/usr/lib/python2.6/site-packages/django/db/models/sql/where.py"", line 94, in as_sql
    sql, params = self.make_atom(child, qn, connection)
  File ""/usr/lib/python2.6/site-packages/django/db/models/sql/where.py"", line 154, in make_atom
    field_sql = self.sql_for_columns(lvalue, qn, connection)
  File ""/usr/lib/python2.6/site-packages/django/db/models/sql/where.py"", line 227, in sql_for_columns
    lhs = '%s.%s' % (qn(table_alias), qn(name))
  File ""/usr/lib/python2.6/site-packages/django/db/models/sql/compiler.py"", line 49, in quote_name_unless_alias
    r = self.connection.ops.quote_name(name)
  File ""/usr/lib/python2.6/site-packages/django/db/backends/sqlite3/base.py"", line 145, in quote_name
    if name.startswith('""') and name.endswith('""'):
AttributeError: 'NoneType' object has no attribute 'startswith'
}}}


Code snippet to reproduce the issue, bug.py:
{{{
from bug.models import *
from django.db.models import Q,Count

qobj=~Q(rtom3__x=0) #TOXIC 
#qobj=~Q(x=0) #OK
#qobj=Q(rtom3__x=0) #OK

qst =  M1.objects.annotate(Count('m2')) #TOXIC
#qst =  M1.objects.all() #OK

qst = qst.filter(qobj)

#Gracefully returns [], no attempt to hit the database!!!!
#print qst

#Throws an exception!
print qst.query
}}}

and models.py:
{{{
from django.db import models

class M1(models.Model):
        rtom3 = models.ForeignKey(""M3"")
        x = models.IntegerField()

class M2(models.Model):
        rtom1 = models.ForeignKey(""M1"") 

class M3(models.Model):
        x = models.IntegerField()
}}}"	Bug	closed	Database layer (models, ORM)	1.4	Normal	fixed	annotate AttributeError		Accepted	0	0	1	0	0	0