TYPO3 Core

type=passthrough can be used to send values to the dataHandler, and passthrough could have an own renderType if you still need something to be displayed.

changing disabled=disabled to readonly would cause hazard in formEngine.

Hi!

I unfortunately must re-open this bug, since some circumstances seem to have changed:

Christian Kuhn wrote:
"type=passthrough can be used to send values to the dataHandler"

This is (no longer?) true. \TYPO3\CMS\Backend\Form\Element\PassThroughElement renders entirely empty - there is no hidden field which would post record data to the DataHandler.

There seems to be a regression now:

1) Create an inline field, e.g. in tt_content for a custom fluid styled content element, holding a list of items

// TCA/Overrides/tt_content.php

    $GLOBALS['TCA']['tt_content']['columns']['my_content_items'] = [
        'label' => $l10nPrefix . 'ContentElements.Generic.ContentItem.title',
        'config' => [
            'type' => 'inline',
            'foreign_table' => 'tx_my_content_item',
            'foreign_field' => 'parent_uid',
            'foreign_table_field' => 'parent_table',
        ],
    ];

2) The child table should have various types, which can be applied depending on the parent (tt_content) CType:

// child table tx_my_content_item

    'columns' => [
        'type' => [
            'exclude' => 0,
            'label' => 'LLL:EXT:frontend/Resources/Private/Language/locallang_ttc.xlf:CType_formlabel',
            'config' => [
                'type' => 'select',
                'renderType' => 'selectSingle',
                'items' => [
                    [
                        $l10nPrefix . 'ContentElements.Generic.MyItemType1.title',
                        'my-item-type-one'
                    ],
                    [
                        $l10nPrefix . 'ContentElements.Generic.MyItemType2.title',
                        'my-item-type-two'
                    ],
                ]
            ]
        ],
        ...
    ],

3) Now register your custom FCE and override the default child type

// TCA/Overrides/tt_content.php

    \TYPO3\CMS\Core\Utility\ExtensionManagementUtility::addPlugin(
        [
            $l10nPrefix . 'ContentElements.MyCustomFCE.title',
            'my_customfce',
            'content-element-my-custom-fce',
        ],
        'CType',
        $extensionKey
    );
    $GLOBALS['TCA']['tt_content']['types']['my_customfce'] = [
        'showitem' => '
            --div--;LLL:EXT:core/Resources/Private/Language/Form/locallang_tabs.xlf:general,
                CType,
                header;LLL:EXT:frontend/Resources/Private/Language/locallang_ttc.xlf:header_formlabel,
                tx_my_content_items;' . $l10nPrefix . 'ContentElements.MyCustomFCE.items,
        ',
        'columnsOverrides' => [
            'tx_my_content_items' => [
                'config' => [
                    'overrideChildTca' => [
                        'columns' => [
                            'type' => [
                                'config' => [
                                    'default' => 'my-item-type-two',
                                ],
                            ],
                        ],
                    ],
                ],
            ],
        ],
    ];

4) Note that this works as long as we display the child type column in showItems, and the type column is rendered as EDITABLE select (which we DO NOT want!)

// child table tx_my_content_item

    'types' => [
        'my-item-type-two' => [
            'showitem' => '
                --div--;LLL:EXT:core/Resources/Private/Language/Form/locallang_tabs.xlf:general,
                    type;LLL:EXT:frontend/Resources/Private/Language/locallang_ttc.xlf:CType_formlabel,
                    header;LLL:EXT:frontend/Resources/Private/Language/locallang_ttc.xlf:header_formlabel,
                    bodytext_primary;LLL:EXT:frontend/Resources/Private/Language/locallang_ttc.xlf:bodytext_formlabel,
            ',
            'columnsOverrides' => [
                'type' => [
                    'config' => [
                        // Darn - nothing here works. No readOnly, no passthrough - only very expensively writing an own renderType. Oh dear gosh, what a regression.
                    ],
                ],
            ],
        ],
        ...
    ],

5) Now try either setting the child table's type column to "'readOnly' => true" (renders fine - submits nothing) or to "'type' => 'passthrough'" (renders nothing - submits nothing).

=> Clearly a regression! There is NO single way, except writing a complicated own renderType (should absolutely not be necessary for such a common use case of passing an inline child's default 'type' and having the datahandler save it).

The only chance you have is to have the child 'type' select field editable and tell the end-user not to edit it. That's catastrophic.

How to fix it?

1) Make 'readOnly' fields render with the html attribute 'readonly', instead of 'disabled'. This is how it should work anyway.

2) Make 'passthrough' render a hidden field, so that (overridden) default values are transferred.

3) Fix the reason for the big fat red warning in https://docs.typo3.org/typo3cms/TCAReference/Types/Index.html#columnsoverrides , make sure default values are not just presentational.

Thanks for listening!

We run into this issue as well! The use-case is

- A custom record child-record has some settings, e.g. a true/false switch and a single-select
- Depending on the parent-record type, some of these settings have to be forced/fixed into a certain state (e.g. false for the switch), which usually works with overrideChildTca.
- The editor is now allowed to change these settings for the certain type, so we tried to set readOnly=TRUE.
- Unfortunately like describe above, the rendering works great, but when we save the record, these record fields falling back to their default values.

The only solution so far is to tell the editors not to change these settings!

TYPO3 v10.4.17
PHP v7.4