I have the following set in my managesieve.inc.php:
$config['managesieve_host'] = 'tls://mail.example.com';
but the sieve plugin for RC continues to try to connect to localhost, as if the above configuration item were not set.
How do I go about debugging why this would be happening? Indeed I have confirmed with some debug printing that:
public function connect($username, $password)
{
// Get connection parameters
$host = $this->rc->config->get('managesieve_host', 'localhost');
is indeed setting $host to localhost.
my guess is a permissions issue on the config file. you asked for a place to debug try this function https://github.com/roundcube/roundcubemail/blob/master/program/lib/Roundcube/rcube_plugin.php#L149 which loads config files for plugins.