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
24788	Allow Forms to set a default prefix attribute	Keryn Knight	Paweł Marczewski	"Example of what I'd like to be able to do:
{{{
from django import forms
class MyForm(forms.Form):
    field = ChoiceField(...)
    prefix = 'myform-is-awesome'

>>> form_itself = MyForm(data=request.GET, files=None)
>>> form_itself.prefix
'myform-is-awesome'
}}}
However this isn't currently workable, because [https://github.com/django/django/blob/master/django/forms/forms.py#L86 self.prefix] is always bound based on the argument given in the arguments, the default of which is `None`

By hoisting the prefix to be a class attribute, and then doing 
{{{
if prefix is not None: 
    self.prefix = prefix
}}}
it seems like forms which ship with apps could effectively namespace themselves such that N overlapping form fields could be POSTed at once and resolved to the correct form.

However, that's only a suggested use-case that hints at why it might be useful to have; the reason I specifically needed this was for validating whether a GET request was likely my filtering form, '''before''' instantiating and validating the data:
{{{
filtered_form = any(x.startswith(MyForm.prefix) for x in request.GET.keys())
}}}
so that I can selectively reset session-saved filters only when a new filterset is done (before then saving validated submitted data back into the session).

My workaround ended up looking like:
{{{
class MyForm(forms.Form):
    prefix = 'woo'
    def __init__(self, *a, *kw):
        super(MyForm, self).__init__(*a, **kw)
        self.prefix = self.__class__.prefix
}}}
which seems a bit ... rubbish."	New feature	closed	Forms	dev	Normal	fixed		django@…	Accepted	1	1	0	0	0	0