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Code Issues 32 Releases Wiki Activity

Fixed #19500 -- Solved a regression in join reuse

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The ORM didn't reuse joins for direct foreign key traversals when using
chained filters. For example:
    qs.filter(fk__somefield=1).filter(fk__somefield=2))
produced two joins.

As a bonus, reverse onetoone filters can now reuse joins correctly

The regression was caused by the join() method refactor in commit
68847135bc

Thanks for Simon Charette for spotting some issues with the first draft
of the patch.
This commit is contained in:
Anssi Kääriäinen
2012-12-20 21:25:48 +02:00
parent c04c03daa3
commit 3dcd435a0e
7 changed files with 65 additions and 32 deletions
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33
tests/regressiontests/queries/tests.py
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@@ -2418,3 +2418,36 @@ class ReverseJoinTrimmingTest(TestCase):
qs = Tag.objects.filter(annotation__tag=t.pk)
self.assertIn('INNER JOIN', str(qs.query))
self.assertEquals(list(qs), [])
class JoinReuseTest(TestCase):
"""
Test that the queries reuse joins sensibly (for example, direct joins
are always reused).
"""
def test_fk_reuse(self):
qs = Annotation.objects.filter(tag__name='foo').filter(tag__name='bar')
self.assertEqual(str(qs.query).count('JOIN'), 1)
def test_fk_reuse_select_related(self):
qs = Annotation.objects.filter(tag__name='foo').select_related('tag')
self.assertEqual(str(qs.query).count('JOIN'), 1)
def test_fk_reuse_annotation(self):
qs = Annotation.objects.filter(tag__name='foo').annotate(cnt=Count('tag__name'))
self.assertEqual(str(qs.query).count('JOIN'), 1)
def test_fk_reuse_disjunction(self):
qs = Annotation.objects.filter(Q(tag__name='foo') | Q(tag__name='bar'))
self.assertEqual(str(qs.query).count('JOIN'), 1)
def test_fk_reuse_order_by(self):
qs = Annotation.objects.filter(tag__name='foo').order_by('tag__name')
self.assertEqual(str(qs.query).count('JOIN'), 1)
def test_revo2o_reuse(self):
qs = Detail.objects.filter(member__name='foo').filter(member__name='foo')
self.assertEqual(str(qs.query).count('JOIN'), 1)
def test_revfk_noreuse(self):
qs = Author.objects.filter(report__name='r4').filter(report__name='r1')
self.assertEqual(str(qs.query).count('JOIN'), 2)