Deprecation: #84725 - sys_domain resolving moved into middleware 

See forge#84725

Description 

The method PageRepository->getDomainStartPage() has been marked as deprecated.

The method TypoScriptFrontendController->findDomainRecord() which was marked as internal, has been removed.

As both methods have been used to resolve the root page ID of the current request, they were solely there to fill $GLOBALS['TSFE']->domainStartPage which is now filled at an earlier stage through the SiteResolver middleware.

Impact 

Calling the PageRepository method will trigger a PHP E_USER_DEPRECATED error.

Calling the TypoScriptFrontendController method will result in a fatal PHP error.

Affected Installations 

TYPO3 installations with third-party extensions calling the methods directly, usually related to resolve a page ID or to mimic a frontend call.

Migration 

If the return value is needed, access $GLOBALS['TSFE']->domainStartPage directly.

If the functionality is used in a third-party functionality and still needed, ensure to extend from SiteResolver middleware to call the now-protected method equivalents instead.