TYPO3 Core

Sorting inline records (let's call them 'parent records') that contain more inline records (let's call these 'children records') in FormEngine results in a mix of uids of parent and children records that are saved within the database.

This only happens when the child records of a parent record are loaded, i.e. if a parent record is/was opened.
I suspect that the FormEngine JavaScript is responsible for getting the newly sorted uids in the correct order: during this search, the correct field is searched, but the different levels of records are not handled correctly.
This is my best guess as to why the wrong UIDs are passed to the DataHandler.

To reproduce add the following TCA/database definitions (or use the files that I added), add a few records and then re-sort the parent records with one of them being open.

"[...]/Configuration/TCA/tx_test_case.php":

<?php

return [
    'ctrl' => [
        'title' => 'IRRE sorting test',
        'label' => 'name'
    ],
    'columns' => [
        'name' => [
           'label' => 'Name',
            'config' => [
                'type' => 'input'
            ]
        ],
        'records' => [
            'label' => 'Parent IRRE records',
            'config' => [
                'type' => 'inline',
                'foreign_table' => 'tx_test_parent',
                'foreign_sortby' => 'sorting',
                'appearance' => [
                    'useSortable' => true,
                    'enabledControls' => [
                        'sort' => true,
                        'dragdrop' => true
                    ]
                ]
            ]
        ]
    ],
    'types' => [
        0 => [
            'showitem' => 'name,records'
        ]
    ]
];

"[...]/Configuration/TCA/tx_test_parent.php":

<?php

return [
    'ctrl' => [
        'title' => 'IRRE sorting test parent record',
        'label' => 'name'
    ],
    'columns' => [
        'name' => [
            'label' => 'Name',
            'config' => [
                'type' => 'input'
            ]
        ],
        'children' => [
            'label' => 'Children IRRE records',
            'config' => [
                'type' => 'inline',
                'foreign_table' => 'tx_test_child',
                'foreign_sortby' => 'sorting',
                'appearance' => [
                    'useSortable' => true,
                    'enabledControls' => [
                        'sort' => true,
                        'dragdrop' => true
                    ]
                ],
            ]
        ]
    ],
    'types' => [
        0 => [
            'showitem' => 'name,children'
        ]
    ]
];

"[...]/Configuration/TCA/tx_test_child.php":

<?php

return [
    'ctrl' => [
        'title' => 'IRRE sorting test child record',
        'label' => 'name'
    ],
    'columns' => [
        'name' => [
            'label' => 'Name',
            'config' => [
                'type' => 'input'
            ]
        ]
    ],
    'types' => [
        0 => [
            'showitem' => 'name'
        ]
    ]
];

"[...]/ext_tables.sql":

CREATE TABLE `tx_test_case` (
    `name` text,
    `records` text
);

CREATE TABLE `tx_test_parent` (
    `name` text,
    `children` text,
    `sorting` int(11) default 0 not null
);

CREATE TABLE `tx_test_child` (
    `name` text,
    `sorting` int(11) default 0 not null
);