Deprecation: #99031 - Deprecated f:format.html in Backend context

See forge#99031

Description

The <f:format.html /> ViewHelper TYPO3\CMS\Fluid\ViewHelpers\Format\HtmlViewHelper should not be used in TYPO3 backend context anymore.

Using this ViewHelper in backend context triggers frontend parseFunc logic, which should be avoided in the backend.

There are other ViewHelpers to output and parse HTML in backend context. See description of the f:sanitize.html ViewHelper for more details.

Impact

Using <f:format.html /> logs a deprecation level warning.

Affected installations

Instances with extensions that come with backend modules using Fluid rendering and accessing <f:format.html /> are affected.

Migration

Switch to one of the other ViewHelpers instead, typically <f:sanitize.html /> to secure a given HTML string, <f:transform.html /> to parse links in HTML, or <f:format.raw /> to output the HTML as is when the input can be considered "secure".