When using a username that doesn't exist in LDAP, we get the following error:
2018/07/09 10:19:54 [error] [php] Undefined variable: userentry (application/core/plugins/AuthLDAP/AuthLDAP.php:515)
Stack trace:
#0 application/core/LSUserIdentity.php(71): LimeSurvey\PluginManager\PluginManager->dispatchEvent()
#1 application/controllers/admin/authentication.php(168): LSUserIdentity->authenticate()
#2 application/controllers/admin/authentication.php(50): prepareLogin()
#3 unknown(0): Authentication->index()
#4 framework/web/actions/CAction.php(109): ReflectionMethod->invokeArgs()
#5 application/core/Survey_Common_Action.php(83): Authentication->runWithParamsInternal()
#6 framework/web/CController.php(308): Authentication->runWithParams()
#7 framework/web/CController.php(286): AdminController->runAction()
#8 framework/web/CController.php(265): AdminController->runActionWithFilters()
#9 application/controllers/AdminController.php(158): AdminController->run()
#10 framework/web/CWebApplication.php(282): AdminController->run()
#11 framework/web/CWebApplication.php(141): LSYii_Application->runController()
#12 framework/base/CApplication.php(185): LSYii_Application->processRequest()
#13 index.php(194): LSYii_Application->run()