Using existing fields of type group with internal_type folder fails with an exception

[mediaessenz]

To reproduce create a content block (content element) with the following yaml config:

name: vendor/test
group: common
fields:
  - identifier: file_folder
    useExistingField: true

The field file_folder in this example come from EXT:bootrap_package and has this old school, but under TYPO3 12 still valid TCA configuration:

$GLOBALS['TCA']['tt_content']['columns']['file_folder'] = [
    'exclude' => true,
    'label' => 'LLL:EXT:bootstrap_package/Resources/Private/Language/Backend.xlf:field.file_folder',
    'config' => [
        'type' => 'group',
        'internal_type' => 'folder',
    ]
];

This is the producted exception in the backend:

(1/1) TypeError
TYPO3\CMS\ContentBlocks\DataProcessing\RelationResolver::getRelations(): Argument #2 ($tableList) must be of type string, null given, called in /var/www/html/vendor/contentblocks/content-blocks/Classes/DataProcessing/RelationResolver.php on line 167

It seems that this backport is not able to handle this old school definition of the newly TYPO3 12 TCA type "folder".

One more thing I realized during debugging is, that the TCA inspector of the TYPO3 Backend shows this field config:

file_folder
  config
    internal_type = folder
    type = folder
  exclude = 1
  label = file_folder

It seems there is some "streamlining on the flow" inside TYPO3 which changes the type group to folder but this seems to happen after content_block reads the tca.

[nhovratov]

Ah, yeah TYPO3's TCA migration happens at the very end, after Content Blocks checks the TCA type. But you can simply define the type beforehand, when you know it:

fields:
  - identifier: file_folder
    useExistingField: true
    type: Folder

You should do this anyway, if the re-used field is defined in TCA/Overrides of another extension: https://docs.typo3.org/p/contentblocks/content-blocks/main/en-us/Guides/ReuseExistingFields/Index.html#reusing-custom-fields

Let me know, if this works.

[mediaessenz]

Nope, but this works for me:

fields: 
  - identifier: file_folder
    type: Folder
    prefixField: false

[nhovratov]

But this would cause the TCA and SQL generation of this field, which we don't want as it is already there. What happens if you use the other way?

[mediaessenz]

I get the exception again.

Just look in the discussion at slack I had with André Kraus today

[nhovratov]

Okay, this might be really a bug then. Thanks. I will investigate.

[nhovratov]

Fixed for the v13 version.

RelationResolver is now a Core feature and based on TcaSchema with migrated TCA.