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
25252	Add a friendly error message when using Queryset.select_related() after values()	2roy999	Y3K	"Trying to use a queryset while using both methods 'values' and 'select_related' will throw an error when trying to use iter.

models:

{{{
class Poll(models.Model):
    name = models.CharField(max_length=50L)

class Entry(models.Model):
    poll = models.ForeignKey(Poll)
    name = models.CharField(max_length=50L)
}}}

code:
{{{
>>> iter(Entry.objects.values('name').select_related('poll'))
}}}

error:
{{{
Traceback (most recent call last):
  File ""<console>"", line 1, in <module>
  File ""/*path_to_project*/env/local/lib/python2.7/site-packages/django/db/models/query.py"", line 162, in __iter__
    self._fetch_all()
  File ""/*path_to_project*/env/local/lib/python2.7/site-packages/django/db/models/query.py"", line 965, in _fetch_all
    self._result_cache = list(self.iterator())
  File ""/*path_to_project*/env/local/lib/python2.7/site-packages/django/db/models/query.py"", line 1085, in iterator
    for row in self.query.get_compiler(self.db).results_iter():
  File ""/*path_to_project*/env/local/lib/python2.7/site-packages/django/db/models/sql/compiler.py"", line 794, in results_iter
    results = self.execute_sql(MULTI)
  File ""/*path_to_project*/env/local/lib/python2.7/site-packages/django/db/models/sql/compiler.py"", line 829, in execute_sql
    sql, params = self.as_sql()
  File ""/*path_to_project*/env/local/lib/python2.7/site-packages/django/db/models/sql/compiler.py"", line 378, in as_sql
    extra_select, order_by, group_by = self.pre_sql_setup()
  File ""/*path_to_project*/env/local/lib/python2.7/site-packages/django/db/models/sql/compiler.py"", line 48, in pre_sql_setup
    self.setup_query()
  File ""/*path_to_project*/env/local/lib/python2.7/site-packages/django/db/models/sql/compiler.py"", line 39, in setup_query
    self.select, self.klass_info, self.annotation_col_map = self.get_select()
  File ""/*path_to_project*/env/local/lib/python2.7/site-packages/django/db/models/sql/compiler.py"", line 207, in get_select
    klass_info['related_klass_infos'] = related_klass_infos
TypeError: 'NoneType' object does not support item assignment

}}}"	Cleanup/optimization	closed	Database layer (models, ORM)	1.8	Normal	fixed	queryset values select_related		Accepted	0	0	0	0	1	0