Deprecation: #90377 - Param types $ref of method callUserFunction

See forge#90377

Description

GeneralUtility::callUserFunction() accepts a reference variable which is used to pass on the caller to the called function. Said variable $ref does not have a type hint, therefore it's possible to hand over any type of variable whilst it's purpose is to only accept objects.

Impact

Passing $ref into GeneralUtility::callUserFunction() with a type other than object or null will trigger a PHP E_USER_DEPRECATED error.

Affected Installations

All installations that pass a non object or non null type $ref variable into GeneralUtility::callUserFunction().

Migration

There is none. $ref is meant to be the calling object. Using it to pass arbitrary data to the user function will eventually be forbidden.