Allow configuring empty_value for SplitPhoneNumberField

[ilkkao]

I'm not sure at all if this my mistake or a real issue. But thought it's easiest to explain it as a PR.

Without this fix, in my django app, a string [] gets saved to the phone_number model view when nothing is entered to the form SplitPhoneNumberField. Model field is defined as:

    phone_number = PhoneNumberField(blank=True, null=True)

Field in my form:

    phone_number = AdminSplitPhoneNumberField(
        required=False,
        help_text='Phone number, country code separated'
    )

In my view I just call

self.form_valid(my_form)

[francoisfreitag]

I've seen your message only recently, I'll investigate this issue.

[francoisfreitag]

Investigated the issue. From the commit message:

Previous behavior was to return an empty list for no data, which is surprising and cannot be saved to a django.db.models.CharField in the database.
Following django.forms.CharField behavior, accepts an empty_value, defaulting to the empty string.

@ilkkao, when you have the chance, could you try out this branch in your project and confirm it solves your issue?

Since your field is nullable, you might need to subclass the SplitPhoneNumberField to specify empty_value=None. Django has some logic to set the empty value to None when the field is nullable, so it might just work out of the box, depending on your project.
https://github.com/django/django/blob/6df19412aabb7d969f5eab4b2ff41269de89b233/django/db/models/fields/__init__.py#L1308

[ilkkao]

I'll add a reminder for myself to comment in couple weeks. I'm travelling currently.

[francoisfreitag]

Thanks!
I noticed the SplitPhoneNumberField is incompatible for use with formfield for the model fields, because the model field specifies a max_length and the form field does not know of it. I’m working on adding max_length to the SplitPhoneNumberField.

[francoisfreitag]

I believe the PR is ready for testing.
I ended up making the empty value configurable, so that users can choose between '' and NULL for storing an empty value in the DB.

After that, I realized it wasn't enough to use the field with fields_for_model, so I added support for the max_length attribute.