Commit 3dddbc0f authored by Tomek Paczkowski's avatar Tomek Paczkowski
Browse files

Fixed #19816: pre-evaluate queryset on m2m set 

In ReverseManyRelatedObjectsDescriptor.__set__, evaluate possible
queryset to avoid problems when clear() would touch data this queryset
returns.
parent 1b7fb29d

django/db/models/fields/related.py

+3 −0
Original line number Diff line number Diff line
@@ -904,6 +904,9 @@ class ReverseManyRelatedObjectsDescriptor(object): 
            raise AttributeError("Cannot set values on a ManyToManyField which specifies an intermediary model.  Use %s.%s's Manager instead." % (opts.app_label, opts.object_name))



        manager = self.__get__(instance)

        # clear() can change expected output of 'value' queryset, we force evaluation

        # of queryset before clear; ticket #19816

        value = tuple(value)

        manager.clear()

        manager.add(*value)

tests/regressiontests/m2m_regress/tests.py

+14 −1
Original line number Diff line number Diff line
@@ -5,7 +5,7 @@ from django.test import TestCase 
from django.utils import six



from .models import (SelfRefer, Tag, TagCollection, Entry, SelfReferChild,

    SelfReferChildSibling, Worksheet, RegressionModelSplit)

    SelfReferChildSibling, Worksheet, RegressionModelSplit, Line)





class M2MRegressionTests(TestCase):
@@ -96,3 +96,16 @@ class M2MRegressionTests(TestCase): 
        # causes a TypeError in add_lazy_relation

        m1 = RegressionModelSplit(name='1')

        m1.save()



    def test_m2m_filter(self):

        worksheet = Worksheet.objects.create(id=1)

        line_hi = Line.objects.create(name="hi")

        line_bye = Line.objects.create(name="bye")



        worksheet.lines = [line_hi, line_bye]

        hi = worksheet.lines.filter(name="hi")



        worksheet.lines = hi

        self.assertEquals(1, worksheet.lines.count())

        self.assertEquals(1, hi.count())