[1.2.X] Fixed #6456 - Excised FileField file deletion to avoid data loss. Thanks to durdinator for the report.

Backport of r15321 from trunk. Backported despite slight backwards-incompatibility due to potential for data loss.

git-svn-id: http://code.djangoproject.com/svn/django/branches/releases/1.2.X@15322 bcc190cf-cafb-0310-a4f2-bffc1f526a37

django/db/models/fields/files.py

@@ -258,19 +258,6 @@ class FileField(Field):
     def contribute_to_class(self, cls, name):
         super(FileField, self).contribute_to_class(cls, name)
         setattr(cls, self.name, self.descriptor_class(self))
-        signals.post_delete.connect(self.delete_file, sender=cls)
-
-    def delete_file(self, instance, sender, **kwargs):
-        file = getattr(instance, self.attname)
-        # If no other object of this type references the file,
-        # and it's not the default value for future objects,
-        # delete it from the backend.
-        if file and file.name != self.default and \
-            not sender._default_manager.filter(**{self.name: file.name}):
-                file.delete(save=False)
-        elif file:
-            # Otherwise, just close the file, so it doesn't tie up resources.
-            file.close()
 
     def get_directory_name(self):
         return os.path.normpath(force_unicode(datetime.datetime.now().strftime(smart_str(self.upload_to))))

docs/releases/1.2.5.txt

@@ -7,7 +7,7 @@ Welcome to Django 1.2.5!
 This is the fifth "bugfix" release in the Django 1.2 series,
 improving the stability and performance of the Django 1.2 codebase.
 
-With one exception, Django 1.2.5 maintains backwards compatibility
+With two exceptions, Django 1.2.5 maintains backwards compatibility
 with Django 1.2.4, but contain a number of fixes and other
 improvements. Django 1.2.5 is a recommended upgrade for any
 development or deployment currently using or targeting Django 1.2.
@@ -15,8 +15,25 @@ development or deployment currently using or targeting Django 1.2.
 For full details on the new features, backwards incompatibilities, and
 deprecated features in the 1.2 branch, see the :doc:`/releases/1.2`.
 
-One backwards incompatibility
-=============================
+Backwards incompatible changes
+==============================
+
+FileField no longer deletes files
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+In earlier Django versions, when a model instance containing a
+:class:`~django.db.models.FileField` was deleted,
+:class:`~django.db.models.FileField` took it upon itself to also delete the
+file from the backend storage. This opened the door to several potentially
+serious data-loss scenarios, including rolled-back transactions and fields on
+different models referencing the same file. In Django 1.2.5,
+:class:`~django.db.models.FileField` will never delete files from the backend
+storage. If you need cleanup of orphaned files, you'll need to handle it
+yourself (for instance, with a custom management command that can be run
+manually or scheduled to run periodically via e.g. cron).
+
+Use of custom SQL to load initial data in tests
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Django provides a custom SQL hooks as a way to inject hand-crafted SQL
 into the database synchronization process. One of the possible uses

tests/modeltests/files/tests.py

@@ -58,11 +58,10 @@ class FileTests(TestCase):
         cache.set("obj2", obj2)
         self.assertEqual(cache.get("obj2").normal.name, "tests/django_test_1.txt")
 
-        # Deleting an object deletes the file it uses, if there are no other
-        # objects still using that file.
+        # Deleting an object does not delete the file it uses.
         obj2.delete()
         obj2.normal.save("django_test.txt", ContentFile("more content"))
-        self.assertEqual(obj2.normal.name, "tests/django_test_1.txt")
+        self.assertEqual(obj2.normal.name, "tests/django_test_2.txt")
 
         # Multiple files with the same name get _N appended to them.
         objs = [Storage() for i in range(3)]