TYPO3 Core

The following-column-example will produce the error `Data Structure ERROR: No [\'ROOT\'][\'el\'] element found in flex form definition.';`. because the file is not resolved.

        'tx_timer_timer' => [
            'exclude' => true,
            'label' => 'LLL:EXT:timer/Resources/Private/Language/locallang_db.xlf:tx_timer_general.field.tx_timer_timer',
            'config' => [
                'type' => 'flex',
                'ds_pointerField' => 'tx_timer_selector',
                'ds' => [
                    'default' => 'EXT:timer/Configuration/FlexForms/TimerDef/Default.xml',
                    'porthDaily' => 'EXT:timer/Configuration/FlexForms/TimerDef/DailyTimer.xml',
                    'porthYearly' => 'EXT:timer/Configuration/FlexForms/TimerDef/YearlyTimer.xml'
                ],
            ],
        ],

In the comment of `parseDataStructureByIdentifier` in TYPO3\CMS\Core\Configuration\FlexForm\FlexFormTools is written:

   * After the data structure definition is found, the method resolves:
     * * FILE:EXT: prefix of the data structure itself - the ds is in a file
     * * FILE:EXT: prefix for sheets - if single sheets are in files
     * * EXT: prefix for sheets - if single sheets are in files (slightly different b/w compat syntax)
     * * Create an sDEF sheet if the data structure has non, yet.

But the method fullfill it not.
Extend in middle of the method `TYPO3\CMS\Core\Configuration\FlexForm\FlexFormTools->parseDataStructureByIdentifier`(line 692ff) the code to fix the problem.

@

// Resolve FILE: prefix pointing to a DS in a file
            if (strpos(trim($dataStructure), 'FILE:') === 0) {
                $file = GeneralUtility::getFileAbsFileName(substr(trim($dataStructure), 5));
                if (empty($file) || !is_file($file)) {
                    throw new \RuntimeException(
                        'Data structure file ' . $file . ' could not be resolved to an existing file',
                        1478105826
                    );
                }
                $dataStructure = file_get_contents($file);
            // } beginn of additional code in Line 692
            } else if (strpos(trim($dataStructure), 'EXT:') === 0) {
                $file = GeneralUtility::getFileAbsFileName(substr(trim($dataStructure), 0));
                if (empty($file) || !@is_file($file)) {
                    throw new \RuntimeException(
                        'Data structure file ' . $file . ' could not be resolved to an existing file',
                        1478105826
                    );
                }
                $dataStructure = file_get_contents($file);
            } // End of additional code

Patch set 1 for branch main of project Packages/TYPO3.CMS has been pushed to the review server.
It is available at https://review.typo3.org/c/Packages/TYPO3.CMS/+/74441

Applied in changeset c9fecd6236d340fc8c34a2f3f9f564cbecb18aa5.