Only update local user cache when userdata has changed

There is no need to update the local user on every login when nothing
has changed.

This should fix most instances of #132 - if the oAuth provider data has
actually updated, the user would have to log into the farmer to update
the data though.

Author: splitbrain

OAuthManager.php

@@ -235,6 +235,9 @@ protected function processUserData($userdata, $servicename)
         $localUser = $auth->getUserByEmail($userdata['mail']);
         if ($localUser) {
             $localUserInfo = $auth->getUserData($localUser);
+            $localUserInfo['user'] = $localUser;
+            if(isset($localUserInfo['pass'])) unset($localUserInfo['pass']);
+
             // check if the user allowed access via this service
             if (!in_array($auth->cleanGroup($servicename), $localUserInfo['grps'])) {
                 throw new Exception('authnotenabled', [$servicename]);
@@ -251,8 +254,12 @@ protected function processUserData($userdata, $servicename)
                 $auth->getConf('overwrite-groups')
             );
 
-            // update user
-            $auth->modifyUser($localUser, $userdata);
+            // update user if changed
+            array_multisort($localUserInfo);
+            array_multisort($userdata);
+            if($localUserInfo != $userdata) {
+                $auth->modifyUser($localUser, $userdata);
+            }
         } elseif (actionOK('register') || $auth->getConf('register-on-auth')) {
             if (!$auth->registerOAuthUser($userdata, $servicename)) {
                 throw new Exception('generic create error');