"MediaWiki internal error" when trying to login

I was trying to login `https://indieweb.org/` with my Github Page (where my blog site deployed).
After I enter the email code and hit enter, I got a bunch of plain text and there's no error from console:


--- ---

## So I need to clear cookies, then access `https://indieweb.org/`

**After I hit continue, here we go again:**

--- ---

## Detail
```
MediaWiki internal error.

Original exception: [b247d8d63a5a3fa9447cd3e6] /wiki/index.php?title=Main_Page UnexpectedValueException: Hook handlers can only return null or a boolean. Got an unexpected value from handler *closure#00000000000000130000000000000000* for AuthRemoteuserFilterUserName
Backtrace:
from /web/sites/indieweb.org/public/wiki/includes/HookContainer/HookContainer.php(172)
#0 /web/sites/indieweb.org/public/wiki/includes/Hooks.php(132): MediaWiki\HookContainer\HookContainer->run()
#1 /web/sites/indieweb.org/public/wiki/extensions/Auth_remoteuser/src/UserNameSessionProvider.php(289): Hooks::run()
#2 /web/sites/indieweb.org/public/wiki/includes/session/SessionManager.php(537): MediaWiki\Extension\Auth_remoteuser\UserNameSessionProvider->provideSessionInfo()
#3 /web/sites/indieweb.org/public/wiki/includes/session/SessionManager.php(244): MediaWiki\Session\SessionManager->getSessionInfoForRequest()
#4 /web/sites/indieweb.org/public/wiki/includes/Request/WebRequest.php(840): MediaWiki\Session\SessionManager->getSessionForRequest()
#5 /web/sites/indieweb.org/public/wiki/includes/session/SessionManager.php(165): MediaWiki\Request\WebRequest->getSession()
#6 /web/sites/indieweb.org/public/wiki/includes/Setup.php(486): MediaWiki\Session\SessionManager::getGlobalSession()
#7 /web/sites/indieweb.org/public/wiki/includes/WebStart.php(92): require_once(string)
#8 /web/sites/indieweb.org/public/wiki/index.php(44): require(string)
#9 {main}

Exception caught inside exception handler: [b247d8d63a5a3fa9447cd3e6] /wiki/index.php?title=Main_Page UnexpectedValueException: Hook handlers can only return null or a boolean. Got an unexpected value from handler *closure#00000000000000130000000000000000* for AuthRemoteuserFilterUserName
Backtrace:
from /web/sites/indieweb.org/public/wiki/includes/HookContainer/HookContainer.php(172)
#0 /web/sites/indieweb.org/public/wiki/includes/Hooks.php(132): MediaWiki\HookContainer\HookContainer->run()
#1 /web/sites/indieweb.org/public/wiki/extensions/Auth_remoteuser/src/UserNameSessionProvider.php(289): Hooks::run()
#2 /web/sites/indieweb.org/public/wiki/includes/session/SessionManager.php(537): MediaWiki\Extension\Auth_remoteuser\UserNameSessionProvider->provideSessionInfo()
#3 /web/sites/indieweb.org/public/wiki/includes/session/SessionManager.php(244): MediaWiki\Session\SessionManager->getSessionInfoForRequest()
#4 /web/sites/indieweb.org/public/wiki/includes/Request/WebRequest.php(840): MediaWiki\Session\SessionManager->getSessionForRequest()
#5 /web/sites/indieweb.org/public/wiki/includes/user/User.php(1024): MediaWiki\Request\WebRequest->getSession()
#6 /web/sites/indieweb.org/public/wiki/includes/user/User.php(393): MediaWiki\User\User->loadDefaults()
#7 /web/sites/indieweb.org/public/wiki/includes/user/User.php(1637): MediaWiki\User\User->load()
#8 /web/sites/indieweb.org/public/wiki/includes/user/User.php(2297): MediaWiki\User\User->getId()
#9 /web/sites/indieweb.org/public/wiki/includes/user/UserOptionsManager.php(656): MediaWiki\User\User->isRegistered()
#10 /web/sites/indieweb.org/public/wiki/includes/user/UserOptionsManager.php(500): MediaWiki\User\UserOptionsManager->getCacheKey()
#11 /web/sites/indieweb.org/public/wiki/includes/user/UserOptionsManager.php(147): MediaWiki\User\UserOptionsManager->loadUserOptions()
#12 /web/sites/indieweb.org/public/wiki/includes/context/RequestContext.php(459): MediaWiki\User\UserOptionsManager->getOption()
#13 /web/sites/indieweb.org/public/wiki/includes/language/Message.php(389): RequestContext->getLanguage()
#14 /web/sites/indieweb.org/public/wiki/includes/language/Message.php(1485): Message->getLanguage()
#15 /web/sites/indieweb.org/public/wiki/includes/language/Message.php(972): Message->fetchMessage()
#16 /web/sites/indieweb.org/public/wiki/includes/language/Message.php(1059): Message->format()
#17 /web/sites/indieweb.org/public/wiki/includes/exception/MWExceptionRenderer.php(254): Message->text()
#18 /web/sites/indieweb.org/public/wiki/includes/exception/MWExceptionRenderer.php(191): MWExceptionRenderer::msg()
#19 /web/sites/indieweb.org/public/wiki/includes/exception/MWExceptionRenderer.php(105): MWExceptionRenderer::reportHTML()
#20 /web/sites/indieweb.org/public/wiki/includes/exception/MWExceptionHandler.php(134): MWExceptionRenderer::output()
#21 /web/sites/indieweb.org/public/wiki/includes/exception/MWExceptionHandler.php(251): MWExceptionHandler::report()
#22 /web/sites/indieweb.org/public/wiki/includes/exception/MWExceptionHandler.php(219): MWExceptionHandler::handleException()
#23 [internal function]: MWExceptionHandler::handleUncaughtException()
#24 {main}
```

Start with extensions/Auth_remoteuser/src/UserNameSessionProvider.php at the provideSessionInfo() call shown in the backtrace, then read includes/HookContainer/HookContainer.php around line 172. Reproduce the login flow and trace the AuthRemoteuserFilterUserName hook result. Done means login reaches the wiki without the MediaWiki internal error.

Written by the indexing model from the issue text.