Feature: #107784 - Autoconfigure backend layout data providers

Description

Backend layout providers are now autoconfigured once they implement the required \TYPO3\CMS\Backend\View\BackendLayout\DataProviderInterface. Each autoconfigured layout provider is tagged with page_layout.data_provider in the service container and is automatically added to the global \TYPO3\CMS\Backend\View\BackendLayout\DataProviderCollection, in case autoconfiguration is enabled in the Services.yaml / Services.php.

Since backend layout providers must be identifiable in order to establish a relation to a configured backend layout, the corresponding interface has been extended. It now requires backend layout providers to implement a new method getIdentifier().

Example:

EXT:my_extension/Classes/View/BackendLayout/MyLayoutDataProvider.php

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

final class MyLayoutDataProvider implements DataProviderInterface
{
    // ...

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

Important

The identifier returned by getIdentifier() must:

Be a non-empty string
Not contain double underscores "__" (used as separator for combined identifiers)
Be unique across all registered backend layout data providers

Example of a combined identifier: my_provider__my_layout

Manual Service Configuration

If autoconfiguration is disabled, manually tag the service in Services.yaml:

EXT:my_extension/Configuration/Services.yaml

services:
  Vendor\MyExtension\View\BackendLayout\MyLayoutDataProvider:
    tags:
      - name: page_layout.data_provider

Provider Ordering

If you need to control the order in which providers are processed, use service priorities in your Services.yaml:

EXT:my_extension/Configuration/Services.yaml

services:
  Vendor\MyExtension\View\BackendLayout\MyLayoutDataProvider:
    tags:
      - name: page_layout.data_provider
        priority: 100

Impact

Backend layout data providers are now automatically registered and can be used without further configuration. This improves developer experience and avoids configuration overload. The previous registration method via $GLOBALS['TYPO3_CONF_VARS']['SC_OPTIONS']['BackendLayoutDataProvider'] can no longer be used. Instead, existing backend layout providers must implement a new method getIdentifier().

Using the new autoconfigure-based approach, developers may still support multiple TYPO3 core versions by having the legacy array-based approach in place next to the new autoconfigure-based approach.