mirrors/django
1
0
Fork 0
mirror of https://github.com/django/django.git synced 2024-12-22 17:16:24 +00:00
Code Issues 25 Releases Wiki Activity

Fixed #30727 -- Made Subquery pickle without evaluating their QuerySet.

Browse Source 
Subquery expression objects, when pickled, were evaluating the QuerySet
objects saved in its _constructor_args attribute.
This commit is contained in:
Andrew Brown 2019-08-27 12:58:11 +02:00 committed by Mariusz Felisiak
parent 03dbdfd9bb
commit 691def10a0
2 changed files with 40 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

5
django/db/models/expressions.py
View File

@ -1019,6 +1019,11 @@ class Subquery(Expression):
self.extra = extra
super().__init__(output_field)
def __getstate__(self):
state = super().__getstate__()
state.pop('_constructor_args', None)
return state
def get_source_expressions(self):
return [self.query]

35
tests/queryset_pickle/tests.py
View File

@ -172,6 +172,41 @@ class PickleabilityTestCase(TestCase):
m2ms = pickle.loads(pickle.dumps(m2ms))
self.assertSequenceEqual(m2ms, [m2m])
def test_pickle_exists_queryset_still_usable(self):
group = Group.objects.create(name='group')
Event.objects.create(title='event', group=group)
groups = Group.objects.annotate(
has_event=models.Exists(
Event.objects.filter(group_id=models.OuterRef('id')),
),
)
groups2 = pickle.loads(pickle.dumps(groups))
self.assertSequenceEqual(groups2.filter(has_event=True), [group])
def test_pickle_exists_queryset_not_evaluated(self):
group = Group.objects.create(name='group')
Event.objects.create(title='event', group=group)
groups = Group.objects.annotate(
has_event=models.Exists(
Event.objects.filter(group_id=models.OuterRef('id')),
),
)
list(groups) # evaluate QuerySet.
with self.assertNumQueries(0):
self.assert_pickles(groups)
def test_pickle_subquery_queryset_not_evaluated(self):
group = Group.objects.create(name='group')
Event.objects.create(title='event', group=group)
groups = Group.objects.annotate(
event_title=models.Subquery(
Event.objects.filter(group_id=models.OuterRef('id')).values('title'),
),
)
list(groups) # evaluate QuerySet.
with self.assertNumQueries(0):
self.assert_pickles(groups)
def test_annotation_with_callable_default(self):
# Happening.when has a callable default of datetime.datetime.now.
qs = Happening.objects.annotate(latest_time=models.Max('when'))