ModelForm should allow passing update_fields to instance.save()

[Václav Řehák]

Model's save() method allows specifying which fields to update using update_fields kwarg (we are investigating this option to finetune db level permissions of our django instances).

However, using this feature with ModelForm is bit inconvenient as ModelForm.save() calls self.instance.save() making it impossible to pass the update_fields to instance.save().

I think that add update_field to ModelForm.save() should be pretty straightforward change without backwards compatibility issues

[Carlton Gibson]

I don't think this is worth the complication. It is easily implemented overriding save:

def save(self, commit=True):
    instance = super().save(commit=False)
    if commit:
        self.instance.save(update_fields=...)
        self._save_m2m()
    return instance

It's a marginal use-case, not justifying adding another Meta option here.