Add a signal at the end of Model.refresh_from_db().

[Craig de Stigter]

I have an app that allows callers to subscribe to a post_save_changed signal on particular fields, when those fields have changed.

It works by recording values in the post_init signal, then checking their values in the post_save signal, and then triggering its own post_save_changed signal if the values are different.

The problem is that currently there's no way this can detect someone calling Model.refresh_from_db(). If I could detect that, I would overwrite the stored values from post_init with some new values. Otherwise my app may detect 'changes' which have actually already been applied to the database.

A post_refresh_from_db signal seems conspicuously absent. Or perhaps post_init should be called again when refresh_from_db is called? That would also solve my problem.

[Craig de Stigter]

Ticket on my app for this: ​https://github.com/craigds/django-fieldsignals/issues/17

[Mariusz Felisiak]

Thanks for this ticket, however I think it's quite niche and even with this signal you will have few missing scenarios e.g. using QuerySet.update() (see #21461).

Needs discussion on the django-developers mailing list in order to be accepted.