Boolean Field should have allow_false (default=True) attribute

[Tanjim Hossain]

I was trying to create 'EmailAddress' model to store multiple emails for an
'user'. The model has and 'is_primary' field with null=True and
unique_together = ('user', 'is_primary')
So if EmailAddress Instance has is_primary set to false, only one primary
email can be set for each user; And that's exactly I want.
but using validator with is_primary(BooleanField) is too much messy work to
do, No!?
Django should come with something like 'allow_false' by default for only
BooleanField

[Jason]

If I understand you right, you want to have multiple emails for a user, but
only one set to primary, but are running into validation errors if a user
has more than one email that is non-primary?

you can set a boolean field to false in default, but I can't see why this
is django's fault? sounds like you're working with a set of requirements
somewhat unique to your project and need custom validation to make sure its
working.

according to the docs on BooleanField,
https://docs.djangoproject.com/en/2.1/ref/models/fields/#booleanfield, if
you don't set a default, it is None by default. That's fairly clear there
and makes sense by following the principle of least surprise
https://en.wikipedia.org/wiki/Principle_of_least_astonishment