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53da1e4794
Previously, you could explicitly assign None to a non-null ForeignKey (or other) field when creating the model (Child(parent=None), etc). We now throw an exception when you do that, which matches the behaviour when you assign None to the attribute after creation. Thanks to ales.zoulek@gmail.com and ondrej.kohout@gmail.com for some analysis of this problem. git-svn-id: http://code.djangoproject.com/svn/django/trunk@9983 bcc190cf-cafb-0310-a4f2-bffc1f526a37
171 lines
5.0 KiB
Python
171 lines
5.0 KiB
Python
"""
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Regression tests for a few ForeignKey bugs.
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"""
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from django.db import models
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# If ticket #1578 ever slips back in, these models will not be able to be
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# created (the field names being lower-cased versions of their opposite
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# classes is important here).
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class First(models.Model):
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second = models.IntegerField()
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class Second(models.Model):
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first = models.ForeignKey(First, related_name = 'the_first')
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# Protect against repetition of #1839, #2415 and #2536.
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class Third(models.Model):
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name = models.CharField(max_length=20)
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third = models.ForeignKey('self', null=True, related_name='child_set')
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class Parent(models.Model):
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name = models.CharField(max_length=20)
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bestchild = models.ForeignKey('Child', null=True, related_name='favored_by')
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class Child(models.Model):
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name = models.CharField(max_length=20)
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parent = models.ForeignKey(Parent)
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# Multiple paths to the same model (#7110, #7125)
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class Category(models.Model):
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name = models.CharField(max_length=20)
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def __unicode__(self):
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return self.name
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class Record(models.Model):
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category = models.ForeignKey(Category)
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class Relation(models.Model):
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left = models.ForeignKey(Record, related_name='left_set')
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right = models.ForeignKey(Record, related_name='right_set')
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def __unicode__(self):
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return u"%s - %s" % (self.left.category.name, self.right.category.name)
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__test__ = {'API_TESTS':"""
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>>> Third.objects.create(id='3', name='An example')
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<Third: Third object>
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>>> parent = Parent(name = 'fred')
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>>> parent.save()
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>>> Child.objects.create(name='bam-bam', parent=parent)
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<Child: Child object>
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#
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# Tests of ForeignKey assignment and the related-object cache (see #6886).
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#
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>>> p = Parent.objects.create(name="Parent")
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>>> c = Child.objects.create(name="Child", parent=p)
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# Look up the object again so that we get a "fresh" object.
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>>> c = Child.objects.get(name="Child")
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>>> p = c.parent
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# Accessing the related object again returns the exactly same object.
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>>> c.parent is p
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True
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# But if we kill the cache, we get a new object.
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>>> del c._parent_cache
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>>> c.parent is p
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False
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# Assigning a new object results in that object getting cached immediately.
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>>> p2 = Parent.objects.create(name="Parent 2")
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>>> c.parent = p2
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>>> c.parent is p2
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True
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# Assigning None succeeds if field is null=True.
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>>> p.bestchild = None
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>>> p.bestchild is None
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True
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# bestchild should still be None after saving.
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>>> p.save()
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>>> p.bestchild is None
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True
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# bestchild should still be None after fetching the object again.
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>>> p = Parent.objects.get(name="Parent")
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>>> p.bestchild is None
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True
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# Assigning None fails: Child.parent is null=False.
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>>> c.parent = None
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Traceback (most recent call last):
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...
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ValueError: Cannot assign None: "Child.parent" does not allow null values.
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# You also can't assign an object of the wrong type here
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>>> c.parent = First(id=1, second=1)
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Traceback (most recent call last):
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...
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ValueError: Cannot assign "<First: First object>": "Child.parent" must be a "Parent" instance.
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# Nor can you explicitly assign None to Child.parent during object creation
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# (regression for #9649).
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>>> Child(name='xyzzy', parent=None)
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Traceback (most recent call last):
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...
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ValueError: Cannot assign None: "Child.parent" does not allow null values.
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>>> Child.objects.create(name='xyzzy', parent=None)
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Traceback (most recent call last):
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...
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ValueError: Cannot assign None: "Child.parent" does not allow null values.
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# Creation using keyword argument should cache the related object.
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>>> p = Parent.objects.get(name="Parent")
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>>> c = Child(parent=p)
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>>> c.parent is p
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True
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# Creation using keyword argument and unsaved related instance (#8070).
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>>> p = Parent()
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>>> c = Child(parent=p)
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>>> c.parent is p
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True
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# Creation using attname keyword argument and an id will cause the related
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# object to be fetched.
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>>> p = Parent.objects.get(name="Parent")
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>>> c = Child(parent_id=p.id)
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>>> c.parent is p
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False
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>>> c.parent == p
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True
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#
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# Test of multiple ForeignKeys to the same model (bug #7125).
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#
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>>> c1 = Category.objects.create(name='First')
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>>> c2 = Category.objects.create(name='Second')
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>>> c3 = Category.objects.create(name='Third')
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>>> r1 = Record.objects.create(category=c1)
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>>> r2 = Record.objects.create(category=c1)
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>>> r3 = Record.objects.create(category=c2)
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>>> r4 = Record.objects.create(category=c2)
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>>> r5 = Record.objects.create(category=c3)
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>>> r = Relation.objects.create(left=r1, right=r2)
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>>> r = Relation.objects.create(left=r3, right=r4)
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>>> r = Relation.objects.create(left=r1, right=r3)
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>>> r = Relation.objects.create(left=r5, right=r2)
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>>> r = Relation.objects.create(left=r3, right=r2)
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>>> Relation.objects.filter(left__category__name__in=['First'], right__category__name__in=['Second'])
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[<Relation: First - Second>]
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>>> Category.objects.filter(record__left_set__right__category__name='Second').order_by('name')
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[<Category: First>, <Category: Second>]
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>>> c2 = Child.objects.create(name="Grandchild", parent=c)
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Traceback (most recent call last):
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...
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ValueError: Cannot assign "<Child: Child object>": "Child.parent" must be a "Parent" instance.
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"""}
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