Forms have list-mutability issues with field validator lists

[brett@…]

from django.forms import Form
from django.forms.fields import IntegerField
from django.core.validators import MinValueValidator

class SampleForm(Form):
    some_field = IntegerField()

    def __init__(self, *args, **kwargs):
        super(SampleForm, self).__init__(*args, **kwargs)
        self.fields['some_field'].validators.append(MinValueValidator(1))

first_form = SampleForm()
print len(first_form.fields['some_field'].validators)
# Prints 1

second_form = SampleForm()
print len(second_form.fields['some_field'].validators)
# Prints 2

I believe this has to do with the fact that the deepcopy method on Field , which does a shallow copy of everything except for 'widget'. I could see two potential solutions here:

• Do a deepcopy on everything (potentially risky)
• Do a deepcopy on validators and any other fields which could potentially be a list.

While searching, I found ticket #4167, which was similar to this, but pertained more to the Field class itself having mutability issues rather than the Form initialization code.

[Claude Paroz]

This has been fixed in #17127 (will be in 1.4)