id	summary	reporter	owner	description	type	status	component	version	severity	resolution	keywords	cc	stage	has_patch	needs_docs	needs_tests	needs_better_patch	easy	ui_ux
6178	ModelForm too many restrictions.	bear330	nobody	"Originally, I used form_for_model for form generation from model and worked fine.

After form_for_model deprecated, I try to use ModelForm instead, but some problems I occurred.

First, I never use form.save() method to save my model instance. My preferred way is to get data from form, do some '''required''' processes, and set it to my model instance then save it.

ModelForm implementation forces me to pass a model instance in form's constructor. This is not backward compatible. All of my view must pass a '''useless''' model instance to it. 

I don't mind to change my code to follow django's new development version, but this parameter is not necessary for people who don't need to use form.save() feature. 
I just want to generate a form from declared model. '''That's all I need.'''.

ModelForm implementation tied 'generate a form from model' feature and 'save a form which generated from model' feature together. This truly bothered me. 

For the same reason, the ModelForm implementation restricts multiple inheritance from two or more form generated from model. All of that are for form.save() method. 

I think the form.save is a great feature in newforms library, but it shouldn't restrict the people who don't need it. All validations can be done in form.save method and can raise exceptions if form is not fulfill the requirement but in form generation.

Thanks."		closed	Forms	dev		invalid	ModelForm, form.save		Unreviewed	0	0	0	0	0	0