Opened 14 years ago

Closed 14 years ago

Last modified 2 years ago

#11765 closed Uncategorized (invalid)

models.DateField(null=True, blank=True) accepts None, but not the empty string ''

Reported by: shmengie Owned by: nobody
Component: Database layer (models, ORM) Version: dev
Severity: Normal Keywords:
Cc: Triage Stage: Unreviewed
Has patch: no Needs documentation: no
Needs tests: yes Patch needs improvement: no
Easy pickings: no UI/UX: no

Description (last modified by Karen Tracey)

For some reason I cannot create a record with

class MyModel(models.Model):
    models.DateField(null=True, blank=True)

It must be either None or a valid date.

Change History (9)

comment:1 Changed 14 years ago by mrts

Summary: models.DateField(null=True, blank=True) accepts None, but not null string ''models.DateField(null=True, blank=True) accepts None, but not the empty string ''

comment:2 Changed 14 years ago by mrts

Component: UncategorizedDatabase layer (models, ORM)
Needs tests: set
Version: 1.1SVN

The problem is that DateField.to_python() (or DateTimeField) doesn't treat '' specially, see source:/django/trunk/django/db/models/fields/

class DateTest(models.Model):
    foo = models.DateField(null=True, blank=True)
>>> d = DateTest(foo='')
Traceback (most recent call last):
  File "/usr/lib/python2.6/dist-packages/django/db/models/fields/", line 474, in to_python
    _('Enter a valid date in YYYY-MM-DD format.'))
ValidationError: Enter a valid date in YYYY-MM-DD format.

comment:3 Changed 14 years ago by Deepak

Resolution: invalid
Status: newclosed

blank=True tells user that they don't have to fill this field, and it doesn't mean that its empty string. Django assign NoneType if empty.

comment:4 in reply to:  2 Changed 14 years ago by Karen Tracey

Description: modified (diff)

Replying to mrts:

The problem is that DateField.to_python() (or DateTimeField) doesn't treat '' specially...

Neither does IntegerField nor FloatField, eg. It's not clear to me why Date fields would/should be singled out for special treatment here. Forms fields consistently handle treating empty strings input as None, but if you are operating at the model level then you need to use None when you mean None, not an empty string.

comment:5 Changed 14 years ago by imbaczek@…

i've got the ValidationError exception in django's own create_update generic view. a ModelForm instance validates fine, but the save() method raises exactly this exception. there's a simple workaround, but IMHO it should be performed by the field instance.

    def clean(self):
        cleaned_data = self.cleaned_data
        end_time = cleaned_data.get('end_time') # this is not None if user left the <input/> empty

        # ... do stuff with data

        if not end_time:
            cleaned_data['end_time'] = None

        return cleaned_data

not sure if it warrants a different ticket.

comment:6 Changed 14 years ago by Tom Clancy

In case it helps anyone else tearing their hair out, here's one other thing to check (see Stack Overflow ticket): if you have any default or helper text in the field, that will blow up on validation before you get to the clean() method.

comment:7 in reply to:  5 Changed 11 years ago by Brendan

Easy pickings: unset
Severity: Normal
Type: Uncategorized
UI/UX: unset

I agree, I just fixed my problem by adding

    def clean(self):
        cleaned_data = super(MyForm, self).clean()
        if not cleaned_data['my_date']:
            cleaned_data['my_date'] = None
        return cleaned_data

to my form. Without this I received the error

ValidationError: [u"'' value has an invalid date format. It must be in YYYY-MM-DD format."]

even though I had blank=True, null=True set in my model and required=False set in my form.

comment:8 Changed 10 years ago by yekibud

I got this error using crispy-forms and not specifying my Date field in Meta.fields. Adding a clean()n method didn't help but adding the Date field back to Meta.fields did.

comment:9 Changed 2 years ago by hakan

same thing happened to me

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