```counterexample
#0 /srv/mediawiki/php-1.32.0-wmf.20/extensions/CentralAuth/includes/specials/SpecialGlobalGroupMembership.php(102): MWExceptionHandler::handleError(integer, string, string, integer, array, array)
#1 /srv/mediawiki/php-1.32.0-wmf.20/includes/specials/SpecialUserrights.php(469): SpecialGlobalGroupMembership->fetchUser(string, boolean)
#2 /srv/mediawiki/php-1.32.0-wmf.20/includes/specials/SpecialUserrights.php(199): UserrightsPage->editUserGroupsForm(string)
#3 /srv/mediawiki/php-1.32.0-wmf.20/includes/specialpage/SpecialPage.php(569): UserrightsPage->execute(string)
#4 /srv/mediawiki/php-1.32.0-wmf.20/includes/specialpage/SpecialPageFactory.php(581): SpecialPage->run(string)
#5 /srv/mediawiki/php-1.32.0-wmf.20/includes/MediaWiki.php(288): MediaWiki\Special\SpecialPageFactory->executePath(Title, RequestContext)
#6 /srv/mediawiki/php-1.32.0-wmf.20/includes/MediaWiki.php(868): MediaWiki->performRequest()
#7 /srv/mediawiki/php-1.32.0-wmf.20/includes/MediaWiki.php(525): MediaWiki->main()
#8 /srv/mediawiki/php-1.32.0-wmf.20/index.php(42): MediaWiki->run()
#9 /srv/mediawiki/w/index.php(3): include(string)
#10 {main}
```
```
lang=php, name=includes/specials/SpecialGlobalGroupMembership.php
101 function fetchUser( $username, $writing = true ) {
102 if ( $username[0] == '#' ) { // <----------------------------------------------- oops
103 $id = intval( substr( $username, 1 ) );
104 $user = CentralAuthGroupMembershipProxy::newFromId( $id );
105
106 if ( !$user ) {
107 return Status::newFatal( 'noname', $id );
108 }
109 } else {
110 $user = CentralAuthGroupMembershipProxy::newFromName( $username );
111
112 if ( !$user ) {
113 return Status::newFatal( 'nosuchusershort', $username );
114 }
115 }
116
117 return Status::newGood( $user );
118 }
```
From Special:GlobalUserRights