Commit bac187c0 authored by Anssi Kääriäinen's avatar Anssi Kääriäinen
Browse files

[1.5.x] Fixed prefetch_related + pickle regressions 

There were a couple of regressions related to field pickling. The
regressions were introduced by QuerySet._known_related_objects caching.

The regressions aren't present in master, the fix was likely in
f403653c.

Fixed #20157, fixed #20257. Also made QuerySets with model=None
picklable.
parent 63cab03f

django/db/models/query.py

+17 −1
Original line number Diff line number Diff line
@@ -68,11 +68,27 @@ class QuerySet(object): 
        """

        # Force the cache to be fully populated.

        len(self)



        obj_dict = self.__dict__.copy()

        obj_dict['_iter'] = None

        obj_dict['_known_related_objects'] = dict(

            (field.name, val) for field, val in self._known_related_objects.items()

        )

        return obj_dict



    def __setstate__(self, obj_dict):

        model = obj_dict['model']

        if model is None:

            # if model is None, then self should be emptyqs and the related

            # objects do not matter.

            self._known_related_objects = {}

        else:

            opts = model._meta

            self._known_related_objects = dict(

                (opts.get_field(field.name if hasattr(field, 'name') else field), val)

                for field, val in obj_dict['_known_related_objects'].items()

            )

        self.__dict__.update(obj_dict)



    def __repr__(self):

        data = list(self[:REPR_OUTPUT_SIZE + 1])

        if len(data) > REPR_OUTPUT_SIZE:

django/db/models/sql/query.py

+11 −6
Original line number Diff line number Diff line
@@ -208,12 +208,17 @@ class Query(object): 
        Unpickling support.

        """

        # Rebuild list of field instances

        opts = obj_dict['model']._meta

        model = obj_dict['model']

        if model is None:

            # if model is None the queryset should be emptyqs. So the

            # select_fields do not matter.

            obj_dict['select_fields'] = []

        else:

            opts = model._meta

            obj_dict['select_fields'] = [

                name is not None and opts.get_field(name) or None

                for name in obj_dict['select_fields']

            ]



        self.__dict__.update(obj_dict)



    def prepare(self):

tests/regressiontests/queryset_pickle/models.py

+13 −0
Original line number Diff line number Diff line
@@ -36,3 +36,16 @@ class Happening(models.Model): 
    number2 = models.IntegerField(blank=True, default=Numbers.get_static_number)

    number3 = models.IntegerField(blank=True, default=Numbers.get_class_number)

    number4 = models.IntegerField(blank=True, default=nn.get_member_number)



class Person(models.Model):

    name = models.CharField(max_length=200)



class SocialProfile(models.Model):

    person = models.ForeignKey(Person)

    friends = models.ManyToManyField('self')



class Post(models.Model):

    post_date = models.DateTimeField(default=datetime.datetime.now)



class Material(models.Model):

    post = models.ForeignKey(Post, related_name='materials')

tests/regressiontests/queryset_pickle/tests.py

+28 −1
Original line number Diff line number Diff line
@@ -5,7 +5,8 @@ import datetime 


from django.test import TestCase



from .models import Group, Event, Happening

from .models import Group, Event, Happening, Person, Post

from django.contrib.auth.models import AnonymousUser





class PickleabilityTestCase(TestCase):
@@ -46,3 +47,29 @@ class PickleabilityTestCase(TestCase): 
        # can't just use assertEqual(original, unpickled)

        self.assertEqual(original.__class__, unpickled.__class__)

        self.assertEqual(original.args, unpickled.args)



    def test_pickle_m2m_prefetch_related(self):

        bob = Person(name="Bob")

        bob.save()

        people = Person.objects.prefetch_related('socialprofile_set')

        dumped = pickle.dumps(people)

        people = pickle.loads(dumped)

        self.assertQuerysetEqual(

            people, [bob], lambda x: x)



    def test_pickle_field_default_prefetch_related(self):

        p1 = Post.objects.create()

        posts = Post.objects.prefetch_related('materials')

        dumped = pickle.dumps(posts)

        posts = pickle.loads(dumped)

        self.assertQuerysetEqual(

            posts, [p1], lambda x: x)



    def test_pickle_emptyqs(self):

        u = AnonymousUser()

        # Use AnonymousUser, as AnonymousUser.groups has qs.model = None

        empty = u.groups.all()

        dumped = pickle.dumps(empty)

        empty = pickle.loads(dumped)

        self.assertQuerysetEqual(

            empty, [])