How to unescape a default value of an input field in Thymeleaf?

I am passing a model object to a view to be used in a form. Nevertheless I need to unescape one of the parameters and Springboot is throwing an error when I use #uris.unescapePathSegment because it can not find the relevant bean

the code

<tr>
    <td colspan="8"><textarea rows="15" cols="150"
        th:field="${#uris.unescapePathSegment(excerpt.comments)}" /></textarea></td>
    <td class="validation-comments" colspan="5"
        th:if="${#fields.hasErrors('excerpt.comments')}"
        th:errors="${excerpt.comments}"></td>
</tr>

the error

java.lang.IllegalStateException: Neither BindingResult nor plain target object for bean name '#uris' available as request attribute

How should I solve this? Is it possible to unescape the parameter in Thymeleaf before I use it in the field or should I unescape it in the controller?

Solution

A th:field can't be an expression. It can only be a selection expression *{...} (see the docs on inputs) that points to a single field on your form-backing bean (th:object). If you actually do need to unescape it, it should be already unescaped by the time you get to *{excerpt.comments}.