update a non-existent field in instance when updating this instance

[beaulian]

Hi,

According to the following code, when we update an instance, whatever we define other fields (not in the Model) in the Schema, these fields will be inserted to the instance, is it a bug?

marshmallow-sqlalchemy/src/marshmallow_sqlalchemy/load_instance_mixin.py

Lines 73 to 76 in d4c7479

	if instance is not None:
	for key, value in data.items():
	setattr(instance, key, value)
	return instance

Thanks

[lafrech]

I would say it is a bug in client code.

Should this lib actively try to catch this?