Commit 011abb7d authored by Anubhav Joshi's avatar Anubhav Joshi Committed by Tim Graham
Browse files

Fixed #19671 -- Added warnings that null and validators are ignored for ManyToManyField. 

Thanks Loic Bistuer and Tim Graham for help and review.
parent 3a85aae2

django/contrib/admin/filters.py

+3 −2
Original line number Diff line number Diff line
@@ -8,6 +8,7 @@ certain test -- e.g. being a DateField or ForeignKey. 
import datetime



from django.db import models

from django.db.models.fields.related import ManyToManyField

from django.core.exceptions import ImproperlyConfigured, ValidationError

from django.utils.encoding import smart_text, force_text

from django.utils.translation import ugettext_lazy as _
@@ -207,8 +208,8 @@ class RelatedFieldListFilter(FieldListFilter): 
                'display': val,

            }

        if (isinstance(self.field, models.related.RelatedObject) and

                self.field.field.null or hasattr(self.field, 'rel') and

                self.field.null):

                (self.field.field.null or isinstance(self.field.field, ManyToManyField)) or

                hasattr(self.field, 'rel') and (self.field.null or isinstance(self.field, ManyToManyField))):

            yield {

                'selected': bool(self.lookup_val_isnull),

                'query_string': cl.get_query_string({

django/db/models/fields/related.py

+26 −0
Original line number Diff line number Diff line
@@ -1899,6 +1899,7 @@ class ManyToManyField(RelatedField): 
        errors = super(ManyToManyField, self).check(**kwargs)

        errors.extend(self._check_unique(**kwargs))

        errors.extend(self._check_relationship_model(**kwargs))

        errors.extend(self._check_ignored_options(**kwargs))

        return errors



    def _check_unique(self, **kwargs):
@@ -1913,6 +1914,31 @@ class ManyToManyField(RelatedField): 
            ]

        return []



    def _check_ignored_options(self, **kwargs):

        warnings = []



        if self.null:

            warnings.append(

                checks.Warning(

                    'null has no effect on ManyToManyField.',

                    hint=None,

                    obj=self,

                    id='fields.W340',

                )

            )



        if len(self._validators) > 0:

            warnings.append(

                checks.Warning(

                    'ManyToManyField does not support validators.',

                    hint=None,

                    obj=self,

                    id='fields.W341',

                )

            )



        return warnings



    def _check_relationship_model(self, from_model=None, **kwargs):

        if hasattr(self.rel.through, '_meta'):

            qualified_model_name = "%s.%s" % (

docs/ref/checks.txt

+2 −0
Original line number Diff line number Diff line
@@ -148,6 +148,8 @@ Related Fields 
* **fields.E338**: The intermediary model ``<through model>`` has no field

  ``<field name>``.

* **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``.



Signals

~~~~~~~

docs/ref/models/fields.txt

+4 −0
Original line number Diff line number Diff line
@@ -1448,6 +1448,10 @@ that control how the relationship functions. 


    If in doubt, leave it to its default of ``True``.



:class:`ManyToManyField` does not support :attr:`~Field.validators`.



:attr:`~Field.null` has no effect since there is no way to require a

relationship at the database level.



.. _ref-onetoone:

tests/admin_filters/models.py

+1 −1
Original line number Diff line number Diff line
@@ -10,7 +10,7 @@ class Book(models.Model): 
    title = models.CharField(max_length=50)

    year = models.PositiveIntegerField(null=True, blank=True)

    author = models.ForeignKey(User, verbose_name="Verbose Author", related_name='books_authored', blank=True, null=True)

    contributors = models.ManyToManyField(User, verbose_name="Verbose Contributors", related_name='books_contributed', blank=True, null=True)

    contributors = models.ManyToManyField(User, verbose_name="Verbose Contributors", related_name='books_contributed', blank=True)

    is_best_seller = models.NullBooleanField(default=0)

    date_registered = models.DateField(null=True)

    no = models.IntegerField(verbose_name='number', blank=True, null=True)  # This field is intentionally 2 characters long. See #16080.