#23964: MySQL: BaseModelFormSet.validate_unique() fails for mixed case;
----------------------------+--------------------
Reporter: jdufresne | Owner: nobody
Type: Bug | Status: new
Component: Forms | Version: 1.7
Severity: Normal | Keywords:
Triage Stage: Unreviewed | Has patch: 0
Easy pickings: 0 | UI/UX: 0
----------------------------+--------------------
Due to MySQL collation rules, two strings differing only by case are
considered equal (`"foo"` is equal to `"FOO"`). If a database field is
unique, upon inserting two rows where the unique field differs only by
case, there will be a unique constraint violation.
If a `modelformset_factory()` is used to create a form set for a model
with a unique field, the user can enter two strings differing only by
case. The `BaseModelFormSet.validate_unique()` does not consider MySQL's
collation rules and considers these two strings different. Upon insertion
in the database, there is a constraint violation. The following ''new''
unit test demonstrates how this could happen. Code:
<https://github.com/jdufresne/django/tree/mysql-formset-duplicates>.
Not sure the correct approach to fix this as other database backends will
happily accept strings differing only by case. So the formset needs to
have some sense of the database backend or whether or not unique fields
should be case sensitive.
{{{
diff --git a/tests/forms_tests/models.py b/tests/forms_tests/models.py
index 82fa005..45d9680 100644
--- a/tests/forms_tests/models.py
+++ b/tests/forms_tests/models.py
@@ -110,3 +110,7 @@ class Cheese(models.Model):
class Article(models.Model):
content = models.TextField()
+
+
+class Tag(models.Model):
+ name = models.CharField(max_length=100, unique=True)
diff --git a/tests/forms_tests/tests/test_formsets.py
b/tests/forms_tests/tests/test_formsets.py
index 94e2704..2e77afd 100644
--- a/tests/forms_tests/tests/test_formsets.py
+++ b/tests/forms_tests/tests/test_formsets.py
@@ -6,8 +6,10 @@ import datetime
from django.forms import (CharField, DateField, FileField, Form,
IntegerField,
SplitDateTimeField, ValidationError, formsets)
from django.forms.formsets import BaseFormSet, formset_factory
+from django.forms.models import modelformset_factory
from django.forms.utils import ErrorList
from django.test import TestCase
+from ..models import Tag
class Choice(Form):
@@ -1213,3 +1215,22 @@ class TestEmptyFormSet(TestCase):
class FileForm(Form):
file = FileField()
self.assertTrue(formset_factory(FileForm,
extra=0)().is_multipart())
+
+
+TagFormSet = modelformset_factory(Tag, fields=['name'])
+
+
+class ModelFormSetTestCase(TestCase):
+ def test_duplicates_mixed_case(self):
+ formset = TagFormSet({
+ 'form-TOTAL_FORMS': 2,
+ 'form-INITIAL_FORMS': 0,
+ 'form-0-name': 'TAG',
+ 'form-1-name': 'tag',
+ })
+ self.assertTrue(formset.is_valid())
+ formset.save()
+ self.assertQuerysetEqual(
+ Tag.objects.all(),
+ ['TAG'],
+ lambda o: o.name)
}}}
When running this test with a MySQL database the test fails with:
{{{
======================================================================
ERROR: test_duplicates_mixed_case
(forms_tests.tests.test_formsets.ModelFormSetTestCase)
----------------------------------------------------------------------
Traceback (most recent call last):
File "/home/jon/devel/django/tests/forms_tests/tests/test_formsets.py",
line 1232, in test_duplicates_mixed_case
formset.save()
File "/home/jon/devel/django/django/forms/models.py", line 638, in save
return self.save_existing_objects(commit) +
self.save_new_objects(commit)
File "/home/jon/devel/django/django/forms/models.py", line 769, in
save_new_objects
self.new_objects.append(self.save_new(form, commit=commit))
File "/home/jon/devel/django/django/forms/models.py", line 621, in
save_new
return form.save(commit=commit)
File "/home/jon/devel/django/django/forms/models.py", line 461, in save
construct=False)
File "/home/jon/devel/django/django/forms/models.py", line 103, in
save_instance
instance.save()
File "/home/jon/devel/django/django/db/models/base.py", line 694, in
save
force_update=force_update, update_fields=update_fields)
File "/home/jon/devel/django/django/db/models/base.py", line 722, in
save_base
updated = self._save_table(raw, cls, force_insert, force_update,
using, update_fields)
File "/home/jon/devel/django/django/db/models/base.py", line 803, in
_save_table
result = self._do_insert(cls._base_manager, using, fields, update_pk,
raw)
File "/home/jon/devel/django/django/db/models/base.py", line 842, in
_do_insert
using=using, raw=raw)
File "/home/jon/devel/django/django/db/models/manager.py", line 86, in
manager_method
return getattr(self.get_queryset(), name)(*args, **kwargs)
File "/home/jon/devel/django/django/db/models/query.py", line 952, in
_insert
return query.get_compiler(using=using).execute_sql(return_id)
File "/home/jon/devel/django/django/db/models/sql/compiler.py", line
930, in execute_sql
cursor.execute(sql, params)
File "/home/jon/devel/django/django/db/backends/utils.py", line 65, in
execute
return self.cursor.execute(sql, params)
File "/home/jon/devel/django/django/db/utils.py", line 95, in __exit__
six.reraise(dj_exc_type, dj_exc_value, traceback)
File "/home/jon/devel/django/django/db/backends/utils.py", line 65, in
execute
return self.cursor.execute(sql, params)
File "/home/jon/devel/django/django/db/backends/mysql/base.py", line
126, in execute
return self.cursor.execute(query, args)
File "/usr/lib64/python2.7/site-packages/MySQLdb/cursors.py", line 174,
in execute
self.errorhandler(self, exc, value)
File "/usr/lib64/python2.7/site-packages/MySQLdb/connections.py", line
36, in defaulterrorhandler
raise errorclass, errorvalue
IntegrityError: (1062, "Duplicate entry 'tag' for key 'name'")
----------------------------------------------------------------------
}}}
--
Ticket URL: <https://code.djangoproject.com/ticket/23964>
Django <https://code.djangoproject.com/>
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