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
28900	QuerySet.values() and values_list() for compound queries fails with annotation.	elliott-omosheye	Simon Charette	"Added failing test to demonstrate 

{{{
    def test_union_values_subquery(self):
        items = Item.objects.filter(creator=OuterRef(""pk""))
        item_authors = Author.objects.annotate(is_creator=Exists(items)).order_by()
        reports = Report.objects.filter(creator=OuterRef(""pk""))
        report_authors = Author.objects.annotate(is_creator=Exists(reports)).order_by()
        all_authors = item_authors.union(report_authors).order_by()
        self.assertEqual(list(all_authors.values_list(""is_creator"", flat=True)), [True, True, True, True])
}}}

silently messes up the data on values/values_list() with an field

{{{
FAIL: test_union_values_subquery (queries.tests.Queries1Tests)
----------------------------------------------------------------------
Traceback (most recent call last):
  File ""/usr/local/lib/python2.7/unittest/case.py"", line 329, in run
    testMethod()
  File ""/usr/src/widget_app/tests/queries/tests.py"", line 95, in test_union_values_subquery
    self.assertEqual(list(all_authors.values_list(""is_creator"", flat=True)), [True, True, True, True])
  File ""/usr/local/lib/python2.7/unittest/case.py"", line 513, in assertEqual
    assertion_func(first, second, msg=msg)
  File ""/usr/local/lib/python2.7/unittest/case.py"", line 742, in assertListEqual
    self.assertSequenceEqual(list1, list2, msg, seq_type=list)
  File ""/usr/local/lib/python2.7/unittest/case.py"", line 724, in assertSequenceEqual
    self.fail(msg)
  File ""/usr/local/lib/python2.7/unittest/case.py"", line 410, in fail
    raise self.failureException(msg)
AssertionError: Lists differ: [True, True, 2, 2, 3, 4, 4] != [True, True, True, True]

First differing element 2:
2
True

First list contains 3 additional elements.
First extra element 4:
3

- [True, True, 2, 2, 3, 4, 4]
+ [True, True, True, True]
}}}

throws error on empty values()/values_list()

{{{
Traceback (most recent call last):
  File ""/usr/local/lib/python2.7/unittest/case.py"", line 329, in run
    testMethod()
  File ""/usr/src/widget_app/tests/queries/tests.py"", line 95, in test_union_values_subquery
    self.assertEqual(list(all_authors.values()), [True, True, True, True])
  File ""/usr/local/lib/python2.7/site-packages/django/db/models/query.py"", line 250, in __iter__
    self._fetch_all()
  File ""/usr/local/lib/python2.7/site-packages/django/db/models/query.py"", line 1118, in _fetch_all
    self._result_cache = list(self._iterable_class(self))
  File ""/usr/local/lib/python2.7/site-packages/django/db/models/query.py"", line 106, in __iter__
    for row in compiler.results_iter(chunked_fetch=self.chunked_fetch):
  File ""/usr/local/lib/python2.7/site-packages/django/db/models/sql/compiler.py"", line 847, in results_iter
    row = self.apply_converters(row, converters)
  File ""/usr/local/lib/python2.7/site-packages/django/db/models/sql/compiler.py"", line 830, in apply_converters
    value = row[pos]
IndexError: list index out of range
}}}

The funny thing is that the produced SQL query is perfectly valid, so it isn't a case of me asking the ORM to do something especially funky. In any case if this is an unsupported action then the ORM should tell you and not produce runtime errors or silently return bad data."	Bug	closed	Database layer (models, ORM)	1.11	Normal	fixed	union, values	David Wobrock David Sanders Tom Carrick Dan LaManna Sylvain Fankhauser	Ready for checkin	1	0	0	0	0	0