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
18166	Allow the formset class to contribute kwargs to form instances	tevans	Sergei Maertens	"When we use a formset, each form is instantiated by the method {{{BaseFormSet._construct_forms()}}}, which is called from {{{BaseFormSet.__init__()}}}

{{{_construct_forms()}}} allows for additional kwargs to be passed through to the individual form constructor, but {{{BaseFormSet.__init__()}}} does not provide any mechanism for kwargs to be passed through to the {{{_construct_forms()}}} call.

Also, we may not be able to supply a static unchanging list of kwargs that should be supplied to each form constructor - the kwargs we want to pass may depend upon the specific instance of the form being instantiated.

I propose the following changes:

Add a {{{form_kwargs}}} argument to {{{BaseFormSet.__init__()}}}. This would be stored on self, and consumed in {{{BaseFormSet._construct_forms()}}}

Add a method, {{{BaseFormSet._kwargs_for_form(self, i)}}}. This method would be called for each form instantiated, passing the index of the form within the formset. The return value of this method would be merged with the form_kwargs supplied in {{{BaseFormSet.__init__()}}} and used to instantiate the form.

With these changes, a user could add additional constructor arguments to all forms by passing in form_kwargs to the formset constructor, and could add additional constructor arguments to specific forms by implementing _kwargs_for_form on a derived BaseFormSet class.

(I found it strange, when {{{BaseFormSet}}} was written, it was clearly intended to be able to pass kwargs to the forms - {{{_construct_form()}}} allows for it, there just is not the plumbing to do so. I worked around this by redefining - copy/pasting - the {{{_construct_forms()}}} method in my derived {{{BaseFormSet}}} class)

Patch doesn't have tests or doc changes, will add if this idea gets traction.

Cheers

Tom"	New feature	closed	Forms	dev	Normal	fixed	forms formset kwargs		Accepted	1	0	0	0	0	0