When running MediaWiki with php 8.0 GA and configured memcached caching, the following warning occur in the logs:
{ "id": "887b3a53be04c25ed5675dca", "type": "ErrorException", "file": "/data/mediawiki/main/includes/libs/objectcache/utils/MemcachedClient.php", "line": 547, "message": "PHP Warning: Resource ID#784 used as offset, casting to integer (784)", "code": 0, "url": "/w/index.php?title=Spezial:Letzte_%C3%84nderungen&hidebots=1&limit=50&days=7&urlversion=2", "caught_by": "mwe_handler", "backtrace": [ { "file": "/data/mediawiki/main/includes/libs/objectcache/utils/MemcachedClient.php", "line": 547, "function": "handleError", "class": "MWExceptionHandler", "type": "::" }, { "file": "/data/mediawiki/main/includes/libs/objectcache/MemcachedPhpBagOStuff.php", "line": 123, "function": "get_multi", "class": "MemcachedClient", "type": "->" }, { "file": "/data/mediawiki/main/includes/libs/objectcache/MediumSpecificBagOStuff.php", "line": 563, "function": "doGetMulti", "class": "MemcachedPhpBagOStuff", "type": "->" }, { "file": "/data/mediawiki/main/includes/libs/objectcache/wancache/WANObjectCache.php", "line": 502, "function": "getMulti", "class": "MediumSpecificBagOStuff", "type": "->" }, { "file": "/data/mediawiki/main/includes/libs/objectcache/wancache/WANObjectCache.php", "line": 422, "function": "getMulti", "class": "WANObjectCache", "type": "->" }, { "file": "/data/mediawiki/main/includes/libs/objectcache/wancache/WANObjectCache.php", "line": 1444, "function": "get", "class": "WANObjectCache", "type": "->" }, { "file": "/data/mediawiki/main/includes/libs/objectcache/wancache/WANObjectCache.php", "line": 1389, "function": "fetchOrRegenerate", "class": "WANObjectCache", "type": "->" }, { "file": "/data/mediawiki/main/includes/user/User.php", "line": 515, "function": "getWithSetCallback", "class": "WANObjectCache", "type": "->" }, { "file": "/data/mediawiki/main/includes/user/User.php", "line": 426, "function": "loadFromCache", "class": "User", "type": "->" }, { "file": "/data/mediawiki/main/includes/user/User.php", "line": 362, "function": "loadFromId", "class": "User", "type": "->" }, { "file": "/data/mediawiki/main/includes/session/UserInfo.php", "line": 89, "function": "load", "class": "User", "type": "->" }, { "file": "/data/mediawiki/main/includes/session/CookieSessionProvider.php", "line": 129, "function": "newFromId", "class": "MediaWiki\\Session\\UserInfo", "type": "::" }, { "file": "/data/mediawiki/main/includes/session/SessionManager.php", "line": 491, "function": "provideSessionInfo", "class": "MediaWiki\\Session\\CookieSessionProvider", "type": "->" }, { "file": "/data/mediawiki/main/includes/session/SessionManager.php", "line": 214, "function": "getSessionInfoForRequest", "class": "MediaWiki\\Session\\SessionManager", "type": "->" }, { "file": "/data/mediawiki/main/includes/WebRequest.php", "line": 826, "function": "getSessionForRequest", "class": "MediaWiki\\Session\\SessionManager", "type": "->" }, { "file": "/data/mediawiki/main/includes/session/SessionManager.php", "line": 136, "function": "getSession", "class": "WebRequest", "type": "->" }, { "file": "/data/mediawiki/main/includes/Setup.php", "line": 722, "function": "getGlobalSession", "class": "MediaWiki\\Session\\SessionManager", "type": "::" }, { "file": "/data/mediawiki/main/includes/WebStart.php", "line": 89, "args": [ "string" ], "function": "require_once" }, { "file": "/data/mediawiki/main/index.php", "line": 44, "args": [ "string" ], "function": "require" } ] }
This was previously (php < 8.0.0) a NOTICE only, however, now is a warning according to rfc engine_warnings.