Django save_m2m() and excluded field

Answer 1

I see you also posted this same question to Django-users. I'll copy the answer I've posted there:

Firstly, it is no use just giving the name of the error. Errors come with tracebacks, for good reason: they allow us to see exactly where the error is occurring, and the context.

Anyway, in your case, there doesn't seem to be any need to use save_m2m. The documentation states:

"Calling save_m2m() is only required if you use save(commit=False)"

In your case, you've already saved the form to get the new_restaurant instance, and you're adding tags to that instance with no problem. The last two calls, to new_restaurant.save() and form.save_m2m(), are unnecessary.

Answer 2

You don't need either of the last two "save" calls. Your tags relation will be implicitly saved by virtue of the add(). I'd just drop those from the code.