Should blank=True, default="" raise a "This field may not be null" validation error?

[Juan Antonio Alvarez]

If you set a model like so:

class Person(models.Model):

    nickname = models.CharField(max_length=50, blank=True, default="")

    (--- some more fields ---)

Then you include the 'nickname' field in the ModelSerializer.

When you send null to this field, you get a "This field may not be null" error. I know I can override the behaviour at a serializer level, but it seems to me that the serializer should accept the null value in this case, since the field has a default value.

What are your thoughts?

[Tom Christie]

> it seems to me that the serializer should accept the null value in this case, since the field has a default value.

I'm pretty sure that happy with our current behavior here, which stands as:

* The field can be *omitted*, because it has a default value.

* Null is an invalid value, and will raise a validation error.

[Chris Foresman]

You also have to consider that by standard practice, text and char fields shouldn't be nullable, because then you have two "non-value" values. By putting `null` for that field in the data sent to the serializer, you are saying explicitly to "set this field to `NULL`, but that's not possible because the field is `VARCHAR(50) NOT NULL`.

So, if the non-value for a field is a blank string, send that as the value. Or, as Tom noted, just omit the field in your input and then the default value is used by the serializer.