Breaking: #107784 - Remove backend layout data provider registration via $GLOBALS 

Description 

The possibility to register backend layout data providers via $GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['BackendLayoutDataProvider'] has been replaced by autoconfiguration using the service tag page_layout.data_provider.

The tag is automatically added when a class implements \TYPO3\CMS\Backend\View\BackendLayout\DataProviderInterface . Manual configuration via Services.yaml remains possible, especially when autoconfiguration is disabled.

Developers need to adapt existing implementations by adding the new method getIdentifier(), as outlined in Feature: #107784 - Autoconfigure backend layout data providers.

Additionally, the possibility to dynamically add backend layout data providers to the global DataProviderCollection via its add() method has been removed. Developers should register their data providers as service definitions in the container as described above.

Impact 

Using the global array $GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['BackendLayoutDataProvider'] to register backend layout data providers has no effect in TYPO3 v14.0 and later.

Affected installations 

All installations that use $GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['BackendLayoutDataProvider'] for backend layout data provider registration are affected.

This registration is typically done in an ext_localconf.php file.

The extension scanner will report such usages.

Migration 

Migrate existing registrations to the new autoconfiguration-based approach.

Before:

use Vendor\MyExtension\View\BackendLayout\MyLayoutDataProvider;

$GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['BackendLayoutDataProvider']['my_provider']
    = MyLayoutDataProvider::class;

After:

use TYPO3\CMS\Backend\View\BackendLayout\DataProviderInterface;

final class MyLayoutDataProvider implements DataProviderInterface
{
    // ...

    public function getIdentifier(): string
    {
        return 'my_provider';
    }
}

If you need to support multiple TYPO3 versions, you can implement both registration methods (via $GLOBALS and via autoconfiguration).

Ensure that getIdentifier() is implemented, which is backward compatible with older TYPO3 versions even if unused.