class_prepared is not a ModelSignal and differs from documentation

[Alex Hill]

A few minor issues with class_prepared:

1. it's documented as a model signal, and so able to be called with lazy references, but it isn't one and can't be.

Model signals sender model can be lazily referenced when connecting a receiver by specifying its full application label.

2. it's documented as being sent after the model is registered, but it's actually sent just before

Sent whenever a model class has been “prepared” – that is, once model has been defined and registered with Django’s model system.

In ModelBase.__new__():

        ...
        new_class._prepare()  # class_prepared.send() is called at the end of this method
        new_class._meta.apps.register_model(new_class._meta.app_label, new_class)
        return new_class

3. it's instantiated with providing_args=["class"], but it doesn't provide a class argument

All three addressed in PR 6628.

[Tim Graham]

#24313 suggests to deprecated the class_prepared signal. Do you see a reason not to move forward with that instead?

[Alex Hill]

I've added some comments in that ticket. I think deprecating the signal is probably a good idea.

Would deprecating the class_prepared and fixing the issues in this ticket be mutually exclusive?