Method _post_clean

django/forms/models.py:479–513

(self)

        self.add_error(None, errors)

    def _post_clean(self):
        opts = self._meta

        exclude = self._get_validation_exclusions()

        # Foreign Keys being used to represent inline relationships
        # are excluded from basic field value validation. This is for two
        # reasons: firstly, the value may not be supplied (#12507; the
        # case of providing new values to the admin); secondly the
        # object being referred to may not yet fully exist (#12749).
        # However, these fields *must* be included in uniqueness checks,
        # so this can't be part of _get_validation_exclusions().
        for name, field in self.fields.items():
            if isinstance(field, InlineForeignKeyField):
                exclude.add(name)

        try:
            self.instance = construct_instance(
                self, self.instance, opts.fields, opts.exclude
            )
        except ValidationError as e:
            self._update_errors(e)

        try:
            self.instance.full_clean(
                exclude=exclude, validate_unique=False, validate_constraints=False
            )
        except ValidationError as e:
            self._update_errors(e)

        # Validate uniqueness and constraints if needed.
        if self._validate_unique:
            self.validate_unique()
        if self._validate_constraints:
            self.validate_constraints()

    def validate_unique(self):
        """