Regression in 94680437a4. Refs #27222.
During INSERT operations, `field.pre_save()` is called to prepare values
for db insertion. The `add` param must be `True` for `auto_now_add`
fields to be populated. The regression commit passed `False`, causing
`auto_now_add` fields to remain `None` when used by other fields, such
as `upload_to` callables.
Thanks Ran Benita for the report.
- Validate filename returned by FileField.upload_to() not a filename
passed to the FileField.generate_filename() (upload_to() may
completely ignored passed filename).
- Allow relative paths (without dot segments) in the generated filename.
Thanks to Jakub Kleň for the report and review.
Thanks to all folks for checking this patch on existing projects.
Thanks Florian Apolloner and Markus Holtermann for the discussion and
implementation idea.
Regression in 0b79eb3691.
When a FileField is set to an instance of File that is not also an
instance of FieldFile, pre_save() passes that object as the contents to
Storage.save(). This allows the file to be moved rather than copied
to the upload destination.
