CODEWITHSUNDEEP
pythondjangodjango-formsundefined-behaviordjango-validation
Antoine Pinsard
Antoine Pinsard

Reputation: 34972

Django unexpectedly sets a field to None when validating a formset

I'm facing a strange issue with django. It seems that when I run is_valid() on the formset, one value of each subform is set to None. To check this, I put two debug lines printing the cleaned_data dict. One at the end of cleaned_qty(), and the other right after is_valid().

Here is the form :

class ProductsForm(forms.Form):
    product_ref     = forms.CharField(max_length=6, widget=forms.HiddenInput)
    product_name    = forms.CharField(max_length=200, widget=forms.HiddenInput)
    unit            = forms.CharField(max_length=16, widget=forms.HiddenInput)
    qty             = forms.DecimalField(max_digits=6, decimal_places=3,
                        widget=forms.TextInput(attrs={'size': 5}))

    def clean_qty(self):
        data = self.cleaned_data

        if data['qty'] < 0:
            raise ValidationError('La quantité doit être positive')

        unit = Unit.objects.get(pk=data['unit'])

        if not unit.accept_dec and '.' in str(data['qty']) \
        and int(str(data['qty']).split('.')[1]) != 0:
            raise ValidationError('La quantité doit être entière')

        print "!!!" + str(data) + "!!!"

ProductsFormSet = formsets.formset_factory(ProductsForm, extra=0,
    can_delete=True)

And here is the beginning of the view :

def cart(request):
    if request.method == 'POST':
        products_formset = ProductsFormSet(request.POST, prefix='products')
        cart_form = CartForm(request.POST, prefix='cart')
        if products_formset.is_valid() and cart_form.is_valid():
            '''
                Create and save the cart
                Send a confirmation email
            '''

            for form in products_formset:
                print "???" + str(form.cleaned_data) + "???"

And the result when I submit my form :

DEBUG:django.db.backends:(0.000) SELECT `catalog_unit`.`value`, `catalog_unit`.`plural_val`, `catalog_unit`.`accept_dec` FROM `catalog_unit` WHERE `catalog_unit`.`value` = 'Truc' ; args=(u'Truc',)
!!!{'product_ref': u'BDL233', 'product_name': u'Bidule', 'unit': u'Truc', 'qty': Decimal('2.2')}!!!
DEBUG:django.db.backends:(0.001) SELECT `catalog_unit`.`value`, `catalog_unit`.`plural_val`, `catalog_unit`.`accept_dec` FROM `catalog_unit` WHERE `catalog_unit`.`value` = 'Truc' ; args=(u'Truc',)
!!!{'product_ref': u'MCH024', 'product_name': u'Machin', 'unit': u'Truc', 'qty': Decimal('1.3')}!!!
DEBUG:django.db.backends:(0.000) SELECT `catalog_unit`.`value`, `catalog_unit`.`plural_val`, `catalog_unit`.`accept_dec` FROM `catalog_unit` WHERE `catalog_unit`.`value` = 'Chacal' ; args=(u'Chacal',)
!!!{'product_ref': u'CHO127', 'product_name': u'Chouette', 'unit': u'Chacal', 'qty': Decimal('3')}!!!
???{'DELETE': False, 'product_ref': u'BDL233', 'product_name': u'Bidule', 'unit': u'Truc', 'qty': None}???
???{'DELETE': False, 'product_ref': u'MCH024', 'product_name': u'Machin', 'unit': u'Truc', 'qty': None}???
???{'DELETE': False, 'product_ref': u'CHO127', 'product_name': u'Chouette', 'unit': u'Chacal', 'qty': None}???

As you can see, the only difference is that qty is set to None.

I don't have any idea from where this behavior can come from.

Thanks in advance for you light.

Upvotes: 0

Views: 250

Answers (1)

Daniel Roseman
Daniel Roseman

Reputation: 599630

All clean_FIELD methods must return the value being validated. So your clean_qty method should have return data['qty'].

Upvotes: 2

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