Skip redundant INSERT query on successful logon when using PHP7

Since PHP 7.0 session_regenerate_id() will cause the old session data update.
This is redundant INSERT query and also produces a record for the session
we don't need anymore.

CHANGELOG

@@ -1,6 +1,7 @@
 CHANGELOG Roundcube Webmail
 ===========================
 
+- Skip redundant INSERT query on successful logon when using PHP7
 - Replace display_version with display_product_version (#5904)
 - Extend disabled_actions config so it accepts also button names (#5903)
 - Handle remote stylesheets the same as remote images, ask the user to allow them (#5994)

program/lib/Roundcube/rcube_session.php

@@ -45,6 +45,7 @@ abstract class rcube_session
     protected $cookiename   = 'roundcube_sessauth';
     protected $ip_check     = false;
     protected $logging      = false;
+    protected $ignore_write = false;
 
 
     /**
@@ -274,11 +275,16 @@ abstract class rcube_session
      * Generate and set new session id
      *
      * @param boolean $destroy If enabled the current session will be destroyed
+     *
      * @return bool
      */
-    public function regenerate_id($destroy=true)
+    public function regenerate_id($destroy = true)
     {
+        // Since PHP 7.0 session_regenerate_id() will cause the old
+        // session data update, we don't need this
+        $this->ignore_write = true;
         session_regenerate_id($destroy);
+        $this->ignore_write = false;
 
         $this->vars = null;
         $this->key  = session_id();

program/lib/Roundcube/rcube_session_db.php

@@ -123,6 +123,10 @@ class rcube_session_db extends rcube_session
      */
     public function write($key, $vars)
     {
+        if ($this->ignore_write) {
+            return true;
+        }
+
         $now = $this->db->now();
 
         $this->db->query("INSERT INTO {$this->table_name}"

program/lib/Roundcube/rcube_session_memcache.php

@@ -126,6 +126,10 @@ class rcube_session_memcache extends rcube_session
      */
     public function write($key, $vars)
     {
+        if ($this->ignore_write) {
+            return true;
+        }
+
         $data   = serialize(array('changed' => time(), 'ip' => $this->ip, 'vars' => $vars));
         $result = $this->memcache->set($key, $data, MEMCACHE_COMPRESSED, $this->lifetime + 60);
 

program/lib/Roundcube/rcube_session_redis.php

@@ -202,6 +202,10 @@ class rcube_session_redis extends rcube_session {
      */
     public function write($key, $vars)
     {
+        if ($this->ignore_write) {
+            return true;
+        }
+
         $data = serialize(array('changed' => time(), 'ip' => $this->ip, 'vars' => $vars));
 
         return $this->redis->setex($key, $this->lifetime + 60, $data);