Raise an exception if Form's empty_permitted and use_required_attribute arguments conflict

[Vlastimil Zíma]

It is possible to easily create a form which does not provide expected behavior. If a form is created with empty_permitted=True, it still renders a required attribute into its inputs, although it clearly shouldn't.

from django import forms

class FooForm(forms.Form):
     foo = forms.CharField()

unicode(FooForm(empty_permitted=True))
>>> u'<tr><th><label for="id_foo">Foo:</label></th><td><input id="id_foo" name="foo" type="text" required /></td></tr>'

I suggest to disable use_required_attribute if empty_permitted is enabled and/or raise exception if both attributes are set up contradictory. Even though empty_permitted is not a documented attribute, incorrect usage should be limited if possible.

[Tim Graham]

Raising an exception if the arguments are in conflict seems like the best approach to me.

[Naveen Yadav]

Hi,

working on my first ticket on django !!

i am raising the ValidatioError from [​https://github.com/django/django/blob/master/django/forms/forms.py#L418

for that couple of test cases are failing because of following :

creating a formset on certain ​https://github.com/django/django/blob/master/django/forms/formsets.py#L170 set empty_permitted to True.
Not sure should we allow error in this case also.

Any pointers will be appreciated.

Thanks.

[Tim Graham]

I expect a ValueError to be raised in BaseForm.__init__() if the values of empty_permitted and use_required_attribute are incompatible. This is a programming error, not a validation error that the user can do anything about.

[Naveen Yadav]

Thanks for suggestion Tim.

I tried raising ValueError which causes lot of tests to fail because of this line​https://github.com/django/django/blob/master/django/forms/formsets.py#L172 all related to formset. I guess when forms are created through formset both values empty_permitted and use_required_attribute are same.

Should i place check if form(s) is created via formset then error should not be raised ?

[Vlastimil Zíma]

If formset create form with empty_permitted, it has to set use_required_attribute to False as well.

[Herbert Fortes]

Hi,

I created a Pull Request to close this ticket:

​https://github.com/django/django/pull/9691

Regards,
Herbert

[Tim Graham <timograham@…>]

In d368784:

Fixed #28171 -- Added an exception if Form's empty_permitted and use_required_attribute arguments conflict.