[1.2.X] Fixed #9161 -- Ensure that ModelMultipleChoiceField respects to_field_name in validation. Thanks to Honza for the report, and Gregor Müllegger for the patch.

Backport of r15587 from trunk.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.2.X@15588 bcc190cf-cafb-0310-a4f2-bffc1f526a37

2 files changed, 23 insertions, 3 deletions

diff --git a/django/forms/models.py b/django/forms/models.py
index 8cd5481e5a..860a748547 100644
--- a/django/forms/models.py
+++ b/django/forms/models.py
@@ -1017,13 +1017,14 @@ class ModelMultipleChoiceField(ModelChoiceField):
             return []
         if not isinstance(value, (list, tuple)):
             raise ValidationError(self.error_messages['list'])
+        key = self.to_field_name or 'pk'
         for pk in value:
             try:
-                self.queryset.filter(pk=pk)
+                self.queryset.filter(**{key: pk})
             except ValueError:
                 raise ValidationError(self.error_messages['invalid_pk_value'] % pk)
-        qs = self.queryset.filter(pk__in=value)
-        pks = set([force_unicode(o.pk) for o in qs])
+        qs = self.queryset.filter(**{'%s__in' % key: value})
+        pks = set([force_unicode(getattr(o, key)) for o in qs])
         for val in value:
             if force_unicode(val) not in pks:
                 raise ValidationError(self.error_messages['invalid_choice'] % val)
diff --git a/tests/modeltests/model_forms/models.py b/tests/modeltests/model_forms/models.py
index 4e7265ba74..d3a08ca760 100644
--- a/tests/modeltests/model_forms/models.py
+++ b/tests/modeltests/model_forms/models.py
@@ -1562,6 +1562,25 @@ ValidationError: [u'Select a valid choice. z is not one of the available choices
 <tr><th><label for="id_description">Description:</label></th><td><input type="text" name="description" id="id_description" /></td></tr>
 <tr><th><label for="id_url">The URL:</label></th><td><input id="id_url" type="text" name="url" maxlength="40" /></td></tr>
 
+# to_field_name should also work on ModelMultipleChoiceField ##################
+
+>>> field = ModelMultipleChoiceField(Inventory.objects.all(), to_field_name='barcode')
+>>> for choice in field.choices:
+...     print choice
+(86, u'Apple')
+(22, u'Pear')
+(87, u'Core')
+>>> field.clean([86])
+[<Inventory: Apple>]
+
+>>> class SelectInventoryForm(forms.Form):
+...     items = ModelMultipleChoiceField(Inventory.objects.all(), to_field_name='barcode')
+>>> form = SelectInventoryForm({'items': [87, 22]})
+>>> form.is_valid()
+True
+>>> form.cleaned_data
+{'items': [<Inventory: Pear>, <Inventory: Core>]}
+
 # Model field that returns None to exclude itself with explicit fields ########
 
 >>> class CustomFieldForExclusionForm(ModelForm):