20399083f4
Since assignments on M2M or reverse FK descriptors is composed of a `clear()`, followed by an `add()`, `clear()` could potentially affect the value of the assigned queryset before the `add()` step; pre-evaluating it solves the problem. This patch fixes the issue for ForeignRelatedObjectsDescriptor, ManyRelatedObjectsDescriptor, and ReverseGenericRelatedObjectsDescriptor. It completes 6cb6e1 which addressed ReverseManyRelatedObjectsDescriptor.
108 lines
4.9 KiB
Python
108 lines
4.9 KiB
Python
from __future__ import unicode_literals
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from django.test import TestCase
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from .models import Reporter, Article
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class ManyToOneNullTests(TestCase):
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def setUp(self):
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# Create a Reporter.
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self.r = Reporter(name='John Smith')
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self.r.save()
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# Create an Article.
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self.a = Article(headline="First", reporter=self.r)
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self.a.save()
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# Create an Article via the Reporter object.
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self.a2 = self.r.article_set.create(headline="Second")
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# Create an Article with no Reporter by passing "reporter=None".
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self.a3 = Article(headline="Third", reporter=None)
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self.a3.save()
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# Create another article and reporter
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self.r2 = Reporter(name='Paul Jones')
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self.r2.save()
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self.a4 = self.r2.article_set.create(headline='Fourth')
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def test_get_related(self):
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self.assertEqual(self.a.reporter.id, self.r.id)
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# Article objects have access to their related Reporter objects.
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r = self.a.reporter
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self.assertEqual(r.id, self.r.id)
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def test_created_via_related_set(self):
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self.assertEqual(self.a2.reporter.id, self.r.id)
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def test_related_set(self):
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# Reporter objects have access to their related Article objects.
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self.assertQuerysetEqual(self.r.article_set.all(),
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['<Article: First>', '<Article: Second>'])
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self.assertQuerysetEqual(self.r.article_set.filter(headline__startswith='Fir'),
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['<Article: First>'])
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self.assertEqual(self.r.article_set.count(), 2)
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def test_created_without_related(self):
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self.assertEqual(self.a3.reporter, None)
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# Need to reget a3 to refresh the cache
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a3 = Article.objects.get(pk=self.a3.pk)
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self.assertRaises(AttributeError, getattr, a3.reporter, 'id')
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# Accessing an article's 'reporter' attribute returns None
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# if the reporter is set to None.
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self.assertEqual(a3.reporter, None)
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# To retrieve the articles with no reporters set, use "reporter__isnull=True".
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self.assertQuerysetEqual(Article.objects.filter(reporter__isnull=True),
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['<Article: Third>'])
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# We can achieve the same thing by filtering for the case where the
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# reporter is None.
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self.assertQuerysetEqual(Article.objects.filter(reporter=None),
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['<Article: Third>'])
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# Set the reporter for the Third article
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self.assertQuerysetEqual(self.r.article_set.all(),
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['<Article: First>', '<Article: Second>'])
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self.r.article_set.add(a3)
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self.assertQuerysetEqual(self.r.article_set.all(),
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['<Article: First>', '<Article: Second>', '<Article: Third>'])
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# Remove an article from the set, and check that it was removed.
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self.r.article_set.remove(a3)
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self.assertQuerysetEqual(self.r.article_set.all(),
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['<Article: First>', '<Article: Second>'])
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self.assertQuerysetEqual(Article.objects.filter(reporter__isnull=True),
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['<Article: Third>'])
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def test_remove_from_wrong_set(self):
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self.assertQuerysetEqual(self.r2.article_set.all(), ['<Article: Fourth>'])
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# Try to remove a4 from a set it does not belong to
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self.assertRaises(Reporter.DoesNotExist, self.r.article_set.remove, self.a4)
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self.assertQuerysetEqual(self.r2.article_set.all(), ['<Article: Fourth>'])
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def test_assign_clear_related_set(self):
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# Use descriptor assignment to allocate ForeignKey. Null is legal, so
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# existing members of set that are not in the assignment set are set null
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self.r2.article_set = [self.a2, self.a3]
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self.assertQuerysetEqual(self.r2.article_set.all(),
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['<Article: Second>', '<Article: Third>'])
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# Clear the rest of the set
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self.r.article_set.clear()
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self.assertQuerysetEqual(self.r.article_set.all(), [])
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self.assertQuerysetEqual(Article.objects.filter(reporter__isnull=True),
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['<Article: First>', '<Article: Fourth>'])
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def test_assign_with_queryset(self):
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# Ensure that querysets used in reverse FK assignments are pre-evaluated
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# so their value isn't affected by the clearing operation in
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# ForeignRelatedObjectsDescriptor.__set__. Refs #19816.
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self.r2.article_set = [self.a2, self.a3]
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qs = self.r2.article_set.filter(id=self.a2.id)
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self.r2.article_set = qs
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self.assertEqual(1, self.r2.article_set.count())
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self.assertEqual(1, qs.count())
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def test_clear_efficiency(self):
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r = Reporter.objects.create()
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for _ in range(3):
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r.article_set.create()
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with self.assertNumQueries(1):
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r.article_set.clear()
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self.assertEqual(r.article_set.count(), 0)
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