Fixed #3534 -- newforms ModelChoiceField and ModelMultipleChoiceField no longer cache choices. Instead, they calculate choices via a fresh database query each time the widget is rendered and clean() is called
git-svn-id: http://code.djangoproject.com/svn/django/trunk@4552 bcc190cf-cafb-0310-a4f2-bffc1f526a37
This commit is contained in:
Adrian Holovaty
parent
5bec651a61
commit
ee96c7eb2d
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@ -3,9 +3,11 @@ Helper functions for creating Form classes from Django models
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and database field objects.
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"""
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from django.utils.translation import gettext
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from util import ValidationError
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from forms import BaseForm, DeclarativeFieldsMetaclass, SortedDictFromList
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from fields import ChoiceField, MultipleChoiceField
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from widgets import Select, SelectMultiple
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from fields import Field, ChoiceField
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from widgets import Select, SelectMultiple, MultipleHiddenInput
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__all__ = ('save_instance', 'form_for_model', 'form_for_instance', 'form_for_fields',
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'ModelChoiceField', 'ModelMultipleChoiceField')
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@ -104,33 +106,81 @@ def form_for_fields(field_list):
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fields = SortedDictFromList([(f.name, f.formfield()) for f in field_list if f.editable])
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return type('FormForFields', (BaseForm,), {'base_fields': fields})
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class QuerySetIterator(object):
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def __init__(self, queryset, empty_label, cache_choices):
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self.queryset, self.empty_label, self.cache_choices = queryset, empty_label, cache_choices
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def __iter__(self):
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if self.empty_label is not None:
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yield (u"", self.empty_label)
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for obj in self.queryset:
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yield (obj._get_pk_val(), str(obj))
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# Clear the QuerySet cache if required.
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if not self.cache_choices:
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self.queryset._result_cache = None
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class ModelChoiceField(ChoiceField):
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"A ChoiceField whose choices are a model QuerySet."
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def __init__(self, queryset, empty_label=u"---------", **kwargs):
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self.model = queryset.model
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choices = [(obj._get_pk_val(), str(obj)) for obj in queryset]
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if empty_label is not None:
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choices = [(u"", empty_label)] + choices
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ChoiceField.__init__(self, choices=choices, **kwargs)
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# This class is a subclass of ChoiceField for purity, but it doesn't
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# actually use any of ChoiceField's implementation.
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def __init__(self, queryset, empty_label=u"---------", cache_choices=False,
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required=True, widget=Select, label=None, initial=None, help_text=None):
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self.queryset = queryset
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self.empty_label = empty_label
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self.cache_choices = cache_choices
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# Call Field instead of ChoiceField __init__() because we don't need
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# ChoiceField.__init__().
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Field.__init__(self, required, widget, label, initial, help_text)
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self.widget.choices = self.choices
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def _get_choices(self):
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# If self._choices is set, then somebody must have manually set
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# the property self.choices. In this case, just return self._choices.
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if hasattr(self, '_choices'):
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return self._choices
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# Otherwise, execute the QuerySet in self.queryset to determine the
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# choices dynamically.
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return QuerySetIterator(self.queryset, self.empty_label, self.cache_choices)
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def _set_choices(self, value):
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# This method is copied from ChoiceField._set_choices(). It's necessary
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# because property() doesn't allow a subclass to overwrite only
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# _get_choices without implementing _set_choices.
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self._choices = self.widget.choices = list(value)
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choices = property(_get_choices, _set_choices)
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def clean(self, value):
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value = ChoiceField.clean(self, value)
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if not value:
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Field.clean(self, value)
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if value in ('', None):
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return None
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try:
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value = self.model._default_manager.get(pk=value)
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except self.model.DoesNotExist:
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value = self.queryset.model._default_manager.get(pk=value)
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except self.queryset.model.DoesNotExist:
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raise ValidationError(gettext(u'Select a valid choice. That choice is not one of the available choices.'))
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return value
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class ModelMultipleChoiceField(MultipleChoiceField):
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class ModelMultipleChoiceField(ModelChoiceField):
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"A MultipleChoiceField whose choices are a model QuerySet."
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def __init__(self, queryset, **kwargs):
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self.model = queryset.model
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MultipleChoiceField.__init__(self, choices=[(obj._get_pk_val(), str(obj)) for obj in queryset], **kwargs)
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hidden_widget = MultipleHiddenInput
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def __init__(self, queryset, cache_choices=False, required=True,
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widget=SelectMultiple, label=None, initial=None, help_text=None):
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super(ModelMultipleChoiceField, self).__init__(queryset, None, cache_choices,
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required, widget, label, initial, help_text)
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def clean(self, value):
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value = MultipleChoiceField.clean(self, value)
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if not value:
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if self.required and not value:
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raise ValidationError(gettext(u'This field is required.'))
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elif not self.required and not value:
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return []
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return self.model._default_manager.filter(pk__in=value)
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if not isinstance(value, (list, tuple)):
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raise ValidationError(gettext(u'Enter a list of values.'))
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final_values = []
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for val in value:
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try:
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obj = self.queryset.model._default_manager.get(pk=val)
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except self.queryset.model.DoesNotExist:
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raise ValidationError(gettext(u'Select a valid choice. %s is not one of the available choices.') % val)
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else:
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final_values.append(obj)
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return final_values
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@ -289,6 +289,46 @@ existing Category instance.
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>>> Category.objects.get(id=3)
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<Category: Third>
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Here, we demonstrate that choices for a ForeignKey ChoiceField are determined
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at runtime, based on the data in the database when the form is displayed, not
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the data in the database when the form is instantiated.
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>>> ArticleForm = form_for_model(Article)
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>>> f = ArticleForm(auto_id=False)
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>>> print f.as_ul()
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<li>Headline: <input type="text" name="headline" maxlength="50" /></li>
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<li>Pub date: <input type="text" name="pub_date" /></li>
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<li>Writer: <select name="writer">
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<option value="" selected="selected">---------</option>
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<option value="1">Mike Royko</option>
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<option value="2">Bob Woodward</option>
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</select></li>
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<li>Article: <textarea name="article"></textarea></li>
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<li>Categories: <select multiple="multiple" name="categories">
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<option value="1">Entertainment</option>
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<option value="2">It's a test</option>
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<option value="3">Third</option>
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</select> Hold down "Control", or "Command" on a Mac, to select more than one.</li>
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>>> Category.objects.create(name='Fourth', url='4th')
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<Category: Fourth>
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>>> Writer.objects.create(name='Carl Bernstein')
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<Writer: Carl Bernstein>
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>>> print f.as_ul()
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<li>Headline: <input type="text" name="headline" maxlength="50" /></li>
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<li>Pub date: <input type="text" name="pub_date" /></li>
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<li>Writer: <select name="writer">
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<option value="" selected="selected">---------</option>
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<option value="1">Mike Royko</option>
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<option value="2">Bob Woodward</option>
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<option value="3">Carl Bernstein</option>
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</select></li>
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<li>Article: <textarea name="article"></textarea></li>
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<li>Categories: <select multiple="multiple" name="categories">
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<option value="1">Entertainment</option>
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<option value="2">It's a test</option>
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<option value="3">Third</option>
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<option value="4">Fourth</option>
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</select> Hold down "Control", or "Command" on a Mac, to select more than one.</li>
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# ModelChoiceField ############################################################
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>>> from django.newforms import ModelChoiceField, ModelMultipleChoiceField
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@ -311,13 +351,30 @@ ValidationError: [u'Select a valid choice. That choice is not one of the availab
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>>> f.clean(2)
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<Category: It's a test>
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# Add a Category object *after* the ModelChoiceField has already been
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# instantiated. This proves clean() checks the database during clean() rather
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# than caching it at time of instantiation.
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>>> Category.objects.create(name='Fifth', url='5th')
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<Category: Fifth>
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>>> f.clean(5)
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<Category: Fifth>
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# Delete a Category object *after* the ModelChoiceField has already been
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# instantiated. This proves clean() checks the database during clean() rather
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# than caching it at time of instantiation.
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>>> Category.objects.get(url='5th').delete()
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>>> f.clean(5)
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Traceback (most recent call last):
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...
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ValidationError: [u'Select a valid choice. That choice is not one of the available choices.']
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>>> f = ModelChoiceField(Category.objects.filter(pk=1), required=False)
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>>> print f.clean('')
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None
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>>> f.clean('')
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>>> f.clean('1')
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<Category: Entertainment>
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>>> f.clean('2')
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>>> f.clean('100')
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Traceback (most recent call last):
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...
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ValidationError: [u'Select a valid choice. That choice is not one of the available choices.']
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@ -345,29 +402,47 @@ ValidationError: [u'This field is required.']
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[<Category: Entertainment>, <Category: It's a test>]
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>>> f.clean((1, '2'))
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[<Category: Entertainment>, <Category: It's a test>]
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>>> f.clean(['nonexistent'])
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>>> f.clean(['100'])
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Traceback (most recent call last):
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...
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ValidationError: [u'Select a valid choice. nonexistent is not one of the available choices.']
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ValidationError: [u'Select a valid choice. 100 is not one of the available choices.']
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>>> f.clean('hello')
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Traceback (most recent call last):
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...
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ValidationError: [u'Enter a list of values.']
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# Add a Category object *after* the ModelChoiceField has already been
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# instantiated. This proves clean() checks the database during clean() rather
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# than caching it at time of instantiation.
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>>> Category.objects.create(id=6, name='Sixth', url='6th')
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<Category: Sixth>
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>>> f.clean([6])
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[<Category: Sixth>]
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# Delete a Category object *after* the ModelChoiceField has already been
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# instantiated. This proves clean() checks the database during clean() rather
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# than caching it at time of instantiation.
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>>> Category.objects.get(url='6th').delete()
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>>> f.clean([6])
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Traceback (most recent call last):
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...
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ValidationError: [u'Select a valid choice. 6 is not one of the available choices.']
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>>> f = ModelMultipleChoiceField(Category.objects.all(), required=False)
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>>> f.clean([])
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[]
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>>> f.clean(())
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[]
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>>> f.clean(['4'])
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>>> f.clean(['10'])
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Traceback (most recent call last):
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...
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ValidationError: [u'Select a valid choice. 4 is not one of the available choices.']
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>>> f.clean(['3', '4'])
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ValidationError: [u'Select a valid choice. 10 is not one of the available choices.']
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>>> f.clean(['3', '10'])
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Traceback (most recent call last):
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...
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ValidationError: [u'Select a valid choice. 4 is not one of the available choices.']
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>>> f.clean(['1', '5'])
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ValidationError: [u'Select a valid choice. 10 is not one of the available choices.']
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>>> f.clean(['1', '10'])
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Traceback (most recent call last):
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...
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ValidationError: [u'Select a valid choice. 5 is not one of the available choices.']
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ValidationError: [u'Select a valid choice. 10 is not one of the available choices.']
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"""}
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