Unexpected RemovedInDjango51Warning due to the import of get_storage_class

[JMSoler7]

This method from the django.core.files.storage module is deprecated as of Django 5.1.

It's easy to reproduce; simply define a custom IMPORT_EXPORT_CELERY_STORAGE in the config settings and reload the application:

/app/.venv/lib/python3.11/site-packages/import_export_celery/fields.py:10: RemovedInDjango51Warning: django.core.files.storage.get_storage_class is deprecated in favor of using django.core.files.storage.storages.
    storage_class = get_storage_class(settings.IMPORT_EXPORT_CELERY_STORAGE)

Upon inspecting the Django documentation (https://docs.djangoproject.com/en/5.0/ref/files/storage/#django.core.files.storage.get_storage_class), there is an explanation to use storages (https://docs.djangoproject.com/en/5.0/ref/files/storage/#django.core.files.storage.storages) instead of the get_storage_class method.

[timthelion]

Can this be fixed in a backwards compatible fashion?

[JMSoler7]

@timthelion I'm going to create a pull request in a few minutes which fits with all versions 😃

[PetrDlouhy]

@JMSoler7 The logic of the PR seems to me to be quite harmful. I have written a comment on the PR, but there are other problems:

• Switching to default storage when InvalidStorageError could lead to very unexpected behavior when there is some problem with the storage. I don't think it is equivalent with defaulting to default storage.
• I don't think the code is backward compatible with applications not using the new STORAGES settings since settings.STORAGES.get("IMPORT_EXPORT_CELERY_STORAGE")["BACKEND"] will throw error if STORAGES are not used.