def populate_validators(self) -> None:
        """
        Prepare self.pre_validators, self.validators, and self.post_validators based on self.type_'s  __get_validators__
        and class validators. This method should be idempotent, e.g. it should be safe to call multiple times
        without mis-configuring the field.
        """
        self.validate_always = getattr(self.type_, 'validate_always', False) or any(
            v.always for v in self.class_validators.values()
        )

        class_validators_ = self.class_validators.values()
        if not self.sub_fields or self.shape == SHAPE_GENERIC:
            get_validators = getattr(self.type_, '__get_validators__', None)
            v_funcs = (
                *[v.func for v in class_validators_ if v.each_item and v.pre],
                *(get_validators() if get_validators else list(find_validators(self.type_, self.model_config))),
                *[v.func for v in class_validators_ if v.each_item and not v.pre],
            )
            self.validators = prep_validators(v_funcs)

        self.pre_validators = []
        self.post_validators = []

        if self.field_info and self.field_info.const:
            self.post_validators.append(make_generic_validator(constant_validator))

        if class_validators_:
            self.pre_validators += prep_validators(v.func for v in class_validators_ if not v.each_item and v.pre)
            self.post_validators += prep_validators(v.func for v in class_validators_ if not v.each_item and not v.pre)

        if self.parse_json:
            self.pre_validators.append(make_generic_validator(validate_json))

        self.pre_validators = self.pre_validators or None
        self.post_validators = self.post_validators or None

        Prepare self.pre_validators, self.validators, and self.post_validators based on self.type_'s  __get_validators__
        and class validators. This method should be idempotent, e.g. it should be safe to call multiple times
        without mis-configuring the field.
        
pydantic/v1/fields.py