Deprecation: #109438 - ext_tables.php in extensions 

Description 

Extensions that still ship an ext_tables.php file will now trigger a PHP E_USER_DEPRECATED error each time the file is loaded during a non-cached request or cache warm-up.

The ext_tables.php file was historically used to register backend modules, page doktypes, user settings, and other runtime configuration. All of these use cases now have dedicated alternatives in modern TYPO3:

• Backend modules: Configuration/Backend/Modules.php
• Backend routes: Configuration/Backend/Routes.php
• User settings: Configuration/TCA/Overrides/be_users.php (see forge#108843)
• Page doktype allowed record types: Configuration/TCA/Overrides/pages.php (see forge#108557)

Impact 

A PHP E_USER_DEPRECATED error is triggered for every third-party extension that still provides an ext_tables.php file whenever ext_tables.php files are loaded without caching, for example during cache warm-up or in development context.

Support for ext_tables.php will be removed in TYPO3 v15.0.

Affected installations 

All installations using third-party extensions that still ship an ext_tables.php file are affected.

Migration 

Move all registrations from ext_tables.php to the appropriate configuration files.

$GLOBALS['TYPO3_USER_SETTINGS']['columns']['myCustomSetting'] = [
    'type' => 'check',
    'label' => 'LLL:EXT:my_ext/Resources/Private/Language/locallang.xlf:myCustomSetting',
];
\TYPO3\CMS\Core\Utility\ExtensionManagementUtility::addFieldsToUserSettings(
    'myCustomSetting',
    'after:emailMeAtLogin'
);

\TYPO3\CMS\Core\Utility\ExtensionManagementUtility::addUserSetting(
    'myCustomSetting',
    [
        'label' => 'LLL:EXT:my_ext/Resources/Private/Language/locallang.xlf:myCustomSetting',
        'config' => [
            'type' => 'check',
            'renderType' => 'checkboxToggle',
        ],
    ],
    'after:emailMeAtLogin'
);

\TYPO3\CMS\Core\Utility\GeneralUtility::makeInstance(
    \TYPO3\CMS\Core\DataHandling\PageDoktypeRegistry::class
)->add(116, [
    'allowedTables' => ['tt_content', 'my_custom_record'],
]);

$GLOBALS['TCA']['pages']['types']['116']['allowedRecordTypes'] = [
    'tt_content',
    'my_custom_record',
];