[1.10.x] Fixed #26900 -- Fixed crash accessing deferred FileFields.

Backport of 7c33aa8a87 from master
This commit is contained in:
Tim Graham 2016-07-15 15:54:11 -04:00
parent 6646a396cc
commit a03ac61332
3 changed files with 19 additions and 3 deletions

View File

@ -167,7 +167,11 @@ class FileDescriptor(object):
# The instance dict contains whatever was originally assigned
# in __set__.
file = instance.__dict__[self.field.name]
if self.field.name in instance.__dict__:
file = instance.__dict__[self.field.name]
else:
instance.refresh_from_db(fields=[self.field.name])
file = getattr(instance, self.field.name)
# If this value is a string (instance.file = "path/to/file") or None
# then we simply wrap it with the appropriate attribute class according
@ -437,9 +441,10 @@ class ImageField(FileField):
Dimensions can be forced to update with force=True, which is how
ImageFileDescriptor.__set__ calls this method.
"""
# Nothing to update if the field doesn't have dimension fields.
# Nothing to update if the field doesn't have dimension fields or if
# the field is deferred.
has_dimension_fields = self.width_field or self.height_field
if not has_dimension_fields:
if not has_dimension_fields or self.attname not in instance.__dict__:
return
# getattr will call the ImageFileDescriptor's __get__ method, which

View File

@ -50,3 +50,7 @@ class FileFieldTests(TestCase):
d = Document.objects.create(myfile='something.txt')
d.refresh_from_db()
self.assertIs(d.myfile.instance, d)
def test_defer(self):
Document.objects.create(myfile='something.txt')
self.assertEqual(Document.objects.defer('myfile')[0].myfile, 'something.txt')

View File

@ -188,6 +188,13 @@ class ImageFieldTests(ImageFieldTestMixin, TestCase):
loaded_p = pickle.loads(dump)
self.assertEqual(p.mugshot, loaded_p.mugshot)
def test_defer(self):
self.PersonModel.objects.create(name='Joe', mugshot=self.file1)
with self.assertNumQueries(1):
qs = list(self.PersonModel.objects.defer('mugshot'))
with self.assertNumQueries(0):
self.assertEqual(qs[0].name, 'Joe')
@skipIf(Image is None, "Pillow is required to test ImageField")
class ImageFieldTwoDimensionsTests(ImageFieldTestMixin, TestCase):