Commit f39b0421 authored by Diego Guimarães's avatar Diego Guimarães Committed by Tim Graham
Browse files

Fixed #23338 -- Added warning when unique=True on ForeigKey 

Thanks Jonathan Lindén for the initial patch, and Tim Graham
and Gabe Jackson for the suggestions.
parent abf87333

django/contrib/auth/tests/test_management.py

+1 −0
Original line number Diff line number Diff line
@@ -153,6 +153,7 @@ class ChangepasswordManagementCommandTestCase(TestCase): 




@skipIfCustomUser

@override_settings(SILENCED_SYSTEM_CHECKS=['fields.W342'])  # ForeignKey(unique=True)

class CreatesuperuserManagementCommandTestCase(TestCase):



    def test_basic_usage(self):

django/db/models/fields/related.py

+15 −0
Original line number Diff line number Diff line
@@ -1710,6 +1710,7 @@ class ForeignKey(ForeignObject): 
    def check(self, **kwargs):

        errors = super(ForeignKey, self).check(**kwargs)

        errors.extend(self._check_on_delete())

        errors.extend(self._check_unique())

        return errors



    def _check_on_delete(self):
@@ -1735,6 +1736,16 @@ class ForeignKey(ForeignObject): 
        else:

            return []



    def _check_unique(self, **kwargs):

        return [

            checks.Warning(

                'Setting unique=True on a ForeignKey has the same effect as using a OneToOneField.',

                hint='ForeignKey(unique=True) is usually better served by a OneToOneField.',

                obj=self,

                id='fields.W342',

            )

        ] if self.unique else []



    def deconstruct(self):

        name, path, args, kwargs = super(ForeignKey, self).deconstruct()

        del kwargs['to_fields']
@@ -1891,6 +1902,10 @@ class OneToOneField(ForeignKey): 
        else:

            setattr(instance, self.attname, data)



    def _check_unique(self, **kwargs):

        # override ForeignKey since check isn't applicable here

        return []





def create_many_to_many_intermediary_model(field, klass):

    from django.db import models

docs/ref/checks.txt

+2 −0
Original line number Diff line number Diff line
@@ -154,6 +154,8 @@ Related Fields 
* **fields.E339**: ``<model>.<field name>`` is not a foreign key to ``<model>``.

* **fields.W340**: ``null`` has no effect on ``ManyToManyField``.

* **fields.W341**: ``ManyToManyField`` does not support ``validators``.

* **fields.W342**: Setting ``unique=True`` on a ``ForeignKey`` has the same

  effect as using a ``OneToOneField``.



Signals

~~~~~~~

tests/admin_checks/tests.py

+5 −0
Original line number Diff line number Diff line
@@ -8,6 +8,7 @@ from django.contrib.contenttypes.admin import GenericStackedInline 
from django.core import checks

from django.core.exceptions import ImproperlyConfigured

from django.test import TestCase

from django.test.utils import override_settings



from .models import Song, Book, Album, TwoAlbumFKAndAnE, City, State, Influence
@@ -34,6 +35,10 @@ class ValidFormFieldsets(admin.ModelAdmin): 
    )





@override_settings(

    SILENCED_SYSTEM_CHECKS=['fields.W342'],  # ForeignKey(unique=True)

    INSTALLED_APPS=['django.contrib.auth', 'django.contrib.contenttypes', 'admin_checks']

)

class SystemChecksTestCase(TestCase):



    def test_checks_are_performed(self):

tests/check_framework/tests.py

+6 −4
Original line number Diff line number Diff line
@@ -8,7 +8,6 @@ from django.apps import apps 
from django.conf import settings

from django.core import checks

from django.core.checks import Error, Warning

from django.core.checks.model_checks import check_all_models

from django.core.checks.registry import CheckRegistry

from django.core.checks.compatibility.django_1_7_0 import check_1_7_compatibility

from django.core.management.base import CommandError
@@ -303,7 +302,10 @@ class CheckFrameworkReservedNamesTests(TestCase): 
            del self.current_models[model]

        apps.clear_cache()



    @override_settings(SILENCED_SYSTEM_CHECKS=['models.E020'])

    @override_settings(

        SILENCED_SYSTEM_CHECKS=['models.E20', 'fields.W342'],  # ForeignKey(unique=True)

        INSTALLED_APPS=['django.contrib.auth', 'django.contrib.contenttypes', 'check_framework']

    )

    def test_model_check_method_not_shadowed(self):

        class ModelWithAttributeCalledCheck(models.Model):

            check = 42
@@ -318,6 +320,7 @@ class CheckFrameworkReservedNamesTests(TestCase): 
            check = models.ForeignKey(ModelWithRelatedManagerCalledCheck)

            article = models.ForeignKey(ModelWithRelatedManagerCalledCheck, related_name='check')



        errors = checks.run_checks()

        expected = [

            Error(

                "The 'ModelWithAttributeCalledCheck.check()' class method is "
@@ -341,5 +344,4 @@ class CheckFrameworkReservedNamesTests(TestCase): 
                id='models.E020'

            ),

        ]



        self.assertEqual(check_all_models(), expected)
 
        self.assertEqual(errors, expected)