TYPO3 Core

Error from 12.4:

(1/1) TypeError

htmlspecialchars(): Argument #1 ($string) must be of type string, int given
in /vendor/typo3/cms-setup/Classes/Controller/SetupModuleController.php line 489

        $html = '<select id="field_' . htmlspecialchars($fieldName) . '" 
            name="data' . $dataAdd . '[' . htmlspecialchars($fieldName) . ']"' .
            $more . '>' . LF;
        foreach ($config['items'] as $key => $optionLabel) {
            $html .= '<option value="' . htmlspecialchars($key) . '"' . ($value == $key ? ' selected="selected"' : '') . '>' . $this->getLabel($optionLabel, '', false) . '</option>' . LF;
        }
        $html .= '</select>';
    }
    break;

According to https://www.php.net/manual/en/language.types.array.php valid decimal ints will be casted to ints. It therefore is not possible to add integer values as strings.

1. Add new custom setting for backend users with integer keys
2. Go to the backend user settings

An example setup could look like this within ext_tables.php:

$GLOBALS['TYPO3_USER_SETTINGS']['columns']['defaultPreviewType'] = [
    'label' => 'defaultPreviewType',
    'type' => 'select',
    'items' => [
        '0' => 'defaultPreviewType.0',
        '50' => 'defaultPreviewType.50',
        '60' => 'defaultPreviewType.60',
    ],
];

TYPO3\CMS\Core\Utility\ExtensionManagementUtility::addFieldsToUserSettings(
    'defaultPreviewType',
    'after:copyLevels'
);