TYPO3 Core

PHP Runtime Deprecation Notice: explode(): Passing null to parameter #2 ($string) of type string is deprecated in /var/www/html/vendor/typo3/cms-core/Classes/Utility/GeneralUtility.php line 935

$result = explode($delimiter, $string) ?: [];

Triggered from /var/www/html/vendor/typo3/cms-backend/Classes/Controller/PageLayoutController.php line 592

$colPosArray = array_unique(GeneralUtility::intExplode(',', $this->colPosList));

The error occurs when the backend layout used does not contain colPos. We use this, for example, to display no colPos in SysFolders, since no content is usually maintained there. TSconfig for the backend layout looks like this:

mod.web_layout.BackendLayouts.empty {
  title = Empty

  config {
    backend_layout {
      colCount = 0
      rowCount = 0
    }
  }
}

The issue seems not to occur in current main, as the effected line was changed as part of a breaking change and does not run into this error.