Class DateField

django/db/models/fields/__init__.py:1464–1596

class DateField(DateTimeCheckMixin, Field):
    empty_strings_allowed = False
    default_error_messages = {
        "invalid": _(
            "“%(value)s” value has an invalid date format. It must be "
            "in YYYY-MM-DD format."
        ),
        "invalid_date": _(
            "“%(value)s” value has the correct format (YYYY-MM-DD) "
            "but it is an invalid date."
        ),
    }
    description = _("Date (without time)")

    def __init__(
        self, verbose_name=None, name=None, auto_now=False, auto_now_add=False, **kwargs
    ):
        self.auto_now, self.auto_now_add = auto_now, auto_now_add
        if auto_now or auto_now_add:
            kwargs["editable"] = False
            kwargs["blank"] = True
        super().__init__(verbose_name, name, **kwargs)

    def _check_fix_default_value(self):
        """
        Warn that using an actual date or datetime value is probably wrong;
        it's only evaluated on server startup.
        """
        if not self.has_default():
            return []

        value = self.default
        if isinstance(value, datetime.datetime):
            value = _to_naive(value).date()
        elif isinstance(value, datetime.date):
            pass
        else:
            # No explicit date / datetime value -- no checks necessary
            return []
        # At this point, value is a date object.
        return self._check_if_value_fixed(value)

    def deconstruct(self):
        name, path, args, kwargs = super().deconstruct()
        if self.auto_now:
            kwargs["auto_now"] = True
        if self.auto_now_add:
            kwargs["auto_now_add"] = True
        if self.auto_now or self.auto_now_add:
            del kwargs["editable"]
            del kwargs["blank"]
        return name, path, args, kwargs

    def get_internal_type(self):
        return "DateField"

    def to_python(self, value):
        if value is None: