[5.1.x] Fixed #35657 -- Made FileField handle db_default values.

Backport of 8deb6bb1fc427762d56646bf7306cbd11fb5bb68 from main.

1 files changed, 7 insertions, 0 deletions

diff --git a/django/db/models/fields/files.py b/django/db/models/fields/files.py
index 7c911f4b23..0716d3599e 100644
--- a/django/db/models/fields/files.py
+++ b/django/db/models/fields/files.py
@@ -9,6 +9,7 @@ from django.core.files.images import ImageFile
 from django.core.files.storage import Storage, default_storage
 from django.core.files.utils import validate_file_name
 from django.db.models import signals
+from django.db.models.expressions import DatabaseDefault
 from django.db.models.fields import Field
 from django.db.models.query_utils import DeferredAttribute
 from django.db.models.utils import AltersData
@@ -197,6 +198,12 @@ class FileDescriptor(DeferredAttribute):
             attr = self.field.attr_class(instance, self.field, file)
             instance.__dict__[self.field.attname] = attr
 
+        # If this value is a DatabaseDefault, initialize the attribute class
+        # for this field with its db_default value.
+        elif isinstance(file, DatabaseDefault):
+            attr = self.field.attr_class(instance, self.field, self.field.db_default)
+            instance.__dict__[self.field.attname] = attr
+
         # Other types of files may be assigned as well, but they need to have
         # the FieldFile interface added to them. Thus, we wrap any other type of
         # File inside a FieldFile (well, the field's attr_class, which is