Deprecation: #106618 - GeneralUtility::resolveBackPath

Description

The method GeneralUtility::resolveBackPath has been marked as deprecated and will be removed in TYPO3 v15.0.

It served as a possibility to remove any relative path segments such as ".." when referencing files or directories, and was especially important before TYPO3 v7, where every TYPO3 Backend had their own route and entrypoint PHP file, but nowadays has been a relict from the past.

Since TYPO3 v13, this method has been even more unrelated as the main entrypoint file for TYPO3 Backend is now the same as the frontend ("htdocs/index.php").

Impact

TYPO3 does not resolve the back path of a reference to a resource and does not "normalize" the path anymore when rendering or referencing the resource in the HTML output - neither in the frontend or backend. It will however continue to work.

Affected installations

TYPO3 installations with custom inclusions in TypoScript, or backend modules referencing files with relative paths, which is very uncommon in the current web era.

Migration

Referencing resources should now be done with the EXT prefix, or relative to the public web path of the TYPO3 installation.

Referencing JavaScript modules (ES6 modules) should be handled via import maps and the module names.