$targetUser->clearInstanceCache(); // T40989
}
- $checkValue = explode( ',', $request->getVal( 'conflictcheck-originalgroups' ) );
+ $conflictCheck = $request->getVal( 'conflictcheck-originalgroups' );
+ $conflictCheck = ( $conflictCheck === '' ) ? [] : explode( ',', $conflictCheck );
$userGroups = $targetUser->getGroups();
- if ( $userGroups !== $checkValue ) {
+ if ( $userGroups !== $conflictCheck ) {
$out->addWikiMsg( 'userrights-conflict' );
} else {
$status = $this->saveUserGroups(